Revisions to Ambient Air Monitoring Regulations

Federal RegisterJan 17, 2006

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 53 and 58

[EPA-HQ-OAR-2004-0018; FRL-8015-9]

RIN 2060-AJ25

Revisions to Ambient Air Monitoring Regulations

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule; amendments.

SUMMARY:

The EPA is proposing to revise the ambient air monitoring requirements for criteria pollutants. This proposal establishes ambient air monitoring requirements in support of the proposed revisions to the National Ambient Air Quality Standards (NAAQS) for particulate matter published elsewhere in today's

Federal Register

, including new minimum monitoring network requirements for PM

10-2.5

and criteria for approval of Federal reference and equivalent methods for PM

10-2.5

(to supplement the Federal reference method for PM

10-2.5

proposed elsewhere in today's

Federal Register

). This proposal also requires each State to operate one to three monitoring stations that take an integrated, multipollutant approach to ambient air monitoring. The proposed amendments modify the requirements for ambient air monitors by focusing requirements on populated areas with air quality problems and significantly reducing the requirements for criteria pollutant monitors that have measured ambient air concentrations well below the applicable NAAQS. Other proposed amendments revise the requirements for reference and equivalent method determinations (including specifications and test procedures) for fine particulate monitors, monitoring network descriptions and periodic assessments, quality assurance, and data certification. The purpose of the proposed amendments is to enhance ambient air quality monitoring to better serve current and future air quality management and research needs.

DATES:

Comments must be received on or before April 17, 2006.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2004-0018, by one of the following methods:

•

http://www.regulations.gov:

Follow the on-line instructions for submitting comments.

• E-mail:

a-and-r-docket@epa.gov.

• Fax: (202) 566-1741.

• Mail: Revisions to Ambient Air Monitoring Regulations, Docket No. EPA-HQ-OAR-2004-0018, Environmental Protection Agency, Mailcode 6102T, 1200 Pennsylvania Ave., NW., Washington, DC 20460. Please include a total of two copies. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17th St., NW., Washington, DC 20503.

• Hand Delivery: EPA Docket Center, 1301 Constitution Avenue, NW., Room B102, Washington, DC 20460. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions:

Direct your comments to Docket ID No. EPA-HQ-OAR-2004-0018. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at

http://www.regulations.gov,

including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through

http://www.regulations.gov

or e-mail. The

http://www.regulations.gov

Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through

http://www.regulations.gov

your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses. For additional information about EPA's public docket, visit the EPA Docket Center homepage at

http://www.epa.gov/epahome/dockets.htm.

Docket:

All documents in the docket are listed in the

http://www.regulations.gov index.

Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in

http://www.regulations.gov

or in hard copy at the Revisions to the Ambient Air Monitoring Regulations Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

For general questions concerning today's proposed amendments, please contact Mr. Lewis Weinstock, U.S. EPA, Office of Air Quality Planning and Standards, Emissions Monitoring and Analysis Division, Ambient Air Monitoring Group (D243-02), Research Triangle Park, North Carolina 27711; telephone number: (919) 541-3661; fax number: (919) 541-1903; e-mail address:

weinstock.lewis@epa.gov.

For technical questions, please contact Mr. Tim Hanley, U.S. EPA, Office of Air Quality Planning and Standards, Emissions Monitoring and Analysis Division, Ambient Air Monitoring Group (D243-02), Research Triangle Park, North Carolina 27711; telephone number: (919) 541-4417; fax number: (919) 541-1903; e-mail address:

hanley.tim@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does This Action Apply to Me?

Categories and entities potentially regulated by this action include:

Category

NAIC code

Examples of regulated entities

Industry

334513

541380

Manufacturer, supplier, distributor, or vendor of ambient air monitoring instruments; analytical laboratories or other monitoring organizations that elect to submit an application for a reference or equivalent method determination under 40 CFR part 53.

Federal government

924110

Federal agencies (that conduct ambient air monitoring similar to that conducted by States under 40 CFR part 58 and that wish EPA to use their monitoring data in the same manner as State data) or that elect to submit an application for a reference or equivalent method determination under 40 CFR part 53.

State/local/tribal government

924110

State, territorial, and local, air quality management programs that are responsible for ambient air monitoring under 40 CFR part 58 or that elect to submit an application for a reference or equivalent method determination under 40 CFR part 53. The proposal also may affect Tribes that conduct ambient air monitoring similar to that conducted by States and that wish EPA to use their monitoring data in the same manner as State monitoring data.

North American Industry Classification System.

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this action. To determine whether your facility or Federal, State, local, or territorial agency would be regulated by this action, you should examine the requirements for reference or equivalent method determinations in 40 CFR part 53, subpart A (General Provisions) and the applicability criteria in 40 CFR 51.1 of EPA's requirements for State implementation plans. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

B. What Should I Consider as I Prepare My Comments for EPA?

Do not submit information containing Confidential Business Information (CBI) to EPA through

www.regulations.gov

or e-mail. Send or deliver information identified as CBI only to the following address: Roberto Morales, OAQPS Document Control Officer (C404-02), U.S. EPA, Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, Attention Docket ID EPA-HQ-OAR-2004-0018. Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

C. Where Can I Get a Copy of This Document and Other Related Information?

In addition to being available in the docket, an electronic copy of today's proposed amendments is also available on the Worldwide Web (WWW) through the Technology Transfer Network (TTN). Following the Administrator's signature, a copy of the proposed amendments will be placed on the TTN's policy and guidance page for newly proposed or promulgated rules at

http://www.epa.gov/ttn/oarpg.

The TTN provides information and technology exchange in various areas of air pollution control.

D. Will There Be a Public Hearing?

Public hearings will be held concurrently with the public hearings on the proposed amendments to the NAAQS for particulate matter published elsewhere in this

Federal Register.

The EPA intends to hold public hearings during February 2006 in Philadelphia, Pennsylvania; Chicago, Illinois; and San Francisco, California. The EPA will announce the date, location, and time of the public hearings in a separate

Federal Register

notice.

E. Did EPA Conduct a Peer Review Before Issuing This Notice?

The EPA sought expert scientific review of the proposed methods, technologies, and approach for ambient air monitoring by the Clean Air Scientific Advisory Committee (CASAC). The CASAC is a Federal advisory committee established to review scientific and technical information and make recommendations to the EPA Administrator on issues related to the air quality criteria and corresponding NAAQS. CASAC constituted a National Ambient Air Monitoring Strategy (NAAMS) Subcommittee in 2003 to provide advice for a strategy for the national ambient air monitoring programs. This subcommittee, which operated over a one-year period, and a new subcommittee on Ambient Air Monitoring and Methods (AAMM), formed in 2004, provided the input for CASAC on its consultations, advisories, and peer-reviewed recommendations to the EPA Administrator.

In July 2003, the CASAC NAAMS Subcommittee held a public meeting to review EPA's draft National Ambient Air Monitoring Strategy document (dated September 6, 2002), which contained technical information underlying planned changes to the ambient air monitoring networks. The EPA continued to consult with the CASAC AAMM Subcommittee throughout the development of the proposed amendments. Public meetings were held in July 2004, December 2004, and September 2005 to discuss the CASAC review of nearly 20 documents concerning methods and technology for measurement of particulate matter (PM); data quality objectives for PM monitoring networks and related performance-based standards for approval of equivalent continuous PM monitors; reconfiguration of ambient air monitoring stations;

and other technical aspects of the proposed amendments. These documents, along with CASAC review comments and other information are available at:

http://www.epa.gov/ttn/amtic/casacinf.html.

“Station” and “site” are used somewhat interchangeably in this notice of proposed rulemaking. When there is a difference “site” generally refers to the location of a monitor, while “station” refers to a suite of measurements at a particular site.

F. How Is This Document Organized?

The information presented in this preamble is organized as follows:

I. General Information

A. Does this action apply to me?

B. What should I consider as I prepare my comments for EPA?

C. Where can I get a copy of this document and other related information?

D. Will there be a public hearing?

E. Did EPA conduct a peer review before issuing this notice?

F. How is this document organized?

II. Overview

A. What is the purpose of today's proposal?

B. What are the major changes proposed to the ambient air monitoring regulations?

C. When would the proposed amendments affect States, local governments, tribes, and other stakeholders?

D. How would EPA implement the new requirements?

III. Background

A. What is the role of ambient air monitoring in air quality management?

B. What is the history of ambient air monitoring?

C. What revisions to the National Ambient Air Quality Standards for particulate matter also are proposed today?

D. How do the monitoring data apply to attainment or nonattainment designations and findings?

IV. Proposed Monitoring Amendments

A. What are the proposed terminology changes?

B. What are the proposed requirements for approval of reference or equivalent methods?

C. What are the proposed requirements for quality assurance programs for the National Ambient Air Monitoring System?

D. What are the proposed monitoring methods for the National Ambient Air Monitoring System?

E. What are the proposed requirements for the number and location of monitors to be operated by State and local agencies?

F. What are the proposed probe and monitoring path siting criteria?

G. What are the proposed data reporting, data certification, and sample retention requirements?

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

H. Executive Order 13211: Actions that Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations

II. Overview

A. What Is the Purpose of Today's Proposal?

The EPA is proposing a number of changes to the ambient air quality monitoring requirements of 40 CFR parts 53 and 58 to ensure that the national network of air monitors will meet the current and future data needs of EPA (and other Federal), State, local, and tribal air quality management agencies. While much of today's proposed rule outlines changes to the monitoring requirements for particulate matter (PM), there are additional changes relating to all the other criteria pollutants (ozone (O

), carbon monoxide (CO), sulfur dioxide (SO

), nitrogen dioxide (NO

), and lead (Pb)) included in this proposal.

Some of these proposed changes are in support of the proposed revisions to the National Ambient Air Quality Standards (NAAQS) for PM in 40 CFR part 50 published elsewhere in today's

Federal Register

These changes are essential to implementation of the proposed NAAQS for PM. Included among these proposed PM-related changes are new provisions for addition to 40 CFR parts 53 and 58 which address approval of methods and PM

10-2.5

monitoring requirements. The added provisions would address federal reference method (FRM) equivalency determinations for continuous PM

10-2.5

monitors and the requirements for the number of PM

10-2.5

monitors a State must deploy. Another important element of the provisions for PM

10-2.5

is a proposal for the conditions under which a PM

10-2.5

monitor may be compared to the PM

10-2.5

NAAQS.

The proposed amendments to the National Ambient Air Quality Standards include revised standards for PM

2.5

(particulate mater with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers) and new standards for PM

10-2.5

(particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers and greater than or equal to a nominal 2.5 micrometers).

A number of amendments to existing provisions for PM

2.5

monitoring are also proposed. These would be important to the implementation of the revised PM

2.5

NAAQS because they take advantage of the experience and insight gained by EPA and the States during the past 7 years of PM

2.5

monitoring. One of the proposed PM

2.5

changes involves the criteria for FRM equivalency determinations for continuous PM

2.5

monitors. We anticipate that this change would allow States to operate continuous monitors at more required monitoring sites, providing more robust data for the PM

2.5

air quality program.

Other proposed changes are based on EPA's assessment that the monitoring regulations are not fully aligned with current data needs and opportunities across all the NAAQS pollutants—including PM but also including O

, CO, SO

, NO

, and Pb. This misalignment has developed over time as ambient conditions have improved for some pollutants. Also, new monitoring technologies have been developed that provide attractive opportunities for obtaining more robust and useful data. The EPA recognized that changes were needed several years ago and since then, we have been developing the specifics of these changes with States and other stakeholders.

This group of proposed changes includes relaxation of some long-standing monitoring requirements which we believe are outdated or unnecessarily inflexible. This group of proposed changes also includes a new requirement for States to operate a new type of multipollutant monitoring station, which we plan to call National Core (NCore) stations. Other proposed changes relate to quality assurance requirements, monitor siting, special purpose monitoring, and data management.

We are proposing both the PM NAAQS review-related changes as well as the overarching NAAQS monitoring system changes together because they are strongly related in terms of regulatory language and in terms of implementation decision making. Resources for ambient monitoring are limited, and the cost of new types of monitoring to meet new requirements such as those for PM

10-2.5

must be offset, at least in part, by reducing resources for lower value types of monitoring. The proposed revisions to the monitoring regulations, when finalized, will improve EPA's and our monitoring partners' abilities to manage available funds to support monitoring activities and create a coordinated, integrated, multipurpose, and flexible monitoring system. In addition, it will be easier for the public to comment on the proposed changes if they are presented together rather than in sequential proposals.

Our work with States and other monitoring program stakeholders has included the development of successive versions of a draft report, “National Ambient Air Monitoring Strategy”. The most recent version, dated December 2005, is available in the public docket. The document describes in more depth the reasons for proposing many of the changes presented in this notice, excluding the changes related to PM

10-2.5.

It also discusses strategy elements that are related to, but separate from, the regulatory provisions in 40 CFR parts 53 and 58 such as funding, training,

etc.

The EPA notes that in the proposed regulatory language for 40 CFR parts 53 and 58, we are reprinting a number of existing provisions without change (for example, a number of definitions in current 58.1). We are doing so solely for the readers' convenience in order that the provisions we are proposing can appear in a single context. The EPA is not reproposing, reconsidering, or otherwise reopening any of these reprinted provisions. We will regard any comments as to these provisions as outside the scope of this proposal.

B. What Are the Major Changes Proposed to the Ambient Air Monitoring Regulations?

The summary of each proposed change given here ends with a reference to the part(s) of section IV of this preamble that describes that change in detail.

• We propose to require States to operate from one to three National Core (NCore) multipollutant monitoring sites.

Monitors at NCore multipollutant sites would be required to measure particles (PM

2.5

, speciated PM

2.5

, PM

10-2.5

), O

, SO

, CO, nitrogen oxides (NO/NO

/NO

), and basic meteorology. Monitors for all the gases except for O

would be required to be more sensitive than standard Federal reference method (FRM)/Federal equivalent method (FEM) monitors, so they could accurately report concentrations that are well below the respective NAAQS but that can be important in the formation of O

and PM. We are not proposing specific locations for these sites, but instead would collaborate on site selection with States individually and through multistate organizations. Our objective is that sites be located in broadly representative urban (about 55 sites) and rural (about 20 sites) locations throughout the country to help characterize regional and urban patterns of air pollution. We expect that in many cases States would collocate these new stations with Photochemical Assessment Monitoring Station (PAMS) sites already measuring O

precursors and/or National Air Toxic Trends Station (NATTS) sites measuring air toxics.

The National Core (NCore) multi-pollutant stations are part of an overall strategy to integrate multiple monitoring networks and measurements, including research grade sites and State and local air monitoring stations (SLAMS). Research grade sites would provide complex, research-grade monitoring data for special studies; the proposed amendments do not include requirements for these sites. SLAMS would include sites needed for National Ambient Air Quality Standard comparisons and other data needs of monitoring agencies. The number and placement of SLAMS monitors would vary according to the pollutant, population, and level of air quality problem. The April 2004 draft version of the National Ambient Air Monitoring Strategy presented a taxonomy in which monitoring stations belonged to three levels, called Level 1 (research sites), Level 2 (what are called NCore multipollutant sites in this notice), and Level 3 (what have been called SLAMS/NAMS (national air monitoring stations) in the past). The three Levels combined were referred to as the NCore System. We have decided to dispense with the three-level taxonomy because it does not encompass all relevant monitoring efforts. We now refer to the collection of all ambient air monitoring—including research sites, all types of monitoring by States and Tribes, and all types of ambient monitoring by Federal agencies—as the National Ambient Air Monitoring System (NAAMS). We are retaining the “NCore” label for the multipollutant sites in particular, because the term with this meaning has become part of the vocabulary of the State/local monitoring community.

These sites would still create points of integration among the existing networks for criteria pollutants, each of which was originally designed with only a single pollutant in mind. Where collocated with sites already measuring O

precursors or air toxics, the degree of integration across pollutants of concern would be even stronger. Data from these NCore sites would be used for several purposes that cannot be served as well using only data available from existing networks. Forecasting of the Air Quality Index (AQI) would be improved by feeding several collocated and interdependent pollutant concentration measurements into an air quality model in near real-time to better represent current conditions, from which the model could provide an improved forecast of O

and particle levels for the public. Studies that track long-term trends of criteria pollutants, and thereby help demonstrate the accountability of implemented emissions control programs, would be improved by utilizing higher-sensitivity monitoring equipment for pollutants whose measured levels are well below the NAAQS. Air quality model development and validation efforts would benefit by having a long-term network of several important and interdependent measurements at improved time-scales (e.g., hourly instead of daily sample concentrations on PM methods) at a network of sites expected to remain in place over many years to allow testing of how well models simulate co-pollutant interactions. Where applicable siting criteria for PM or O

monitoring stations are met, NCore sites could also be used to satisfy minimum monitoring requirements for PM and O

and data from these stations could be used in designation decisions and in development of control strategies.

The NCore proposals are described more fully in section IV.E.1 of this preamble.

While not a part of our rationale for requiring States to operate these sites, we note that the data from them will also be of use in future health effects studies.

• We propose monitoring requirements for PM

10-2.5

which are based on deploying a network of FEM monitors that would be approved based on criteria for comparability to monitors utilizing the FRM proposed elsewhere in today's

Federal Register

. Requirements for PM

10-2.5

Class I, Class II, and Class III candidate equivalent methods would be established. The definition of a “Class III equivalent method” would allow for designation of continuous and semi-continuous ambient air monitoring methods for PM

10-2.5

Because we intend that most of the monitors used in the PM

10-2.5

network will use continuous or semi-continuous equivalent methods, the proposal for Class III approval requirements is particularly important for PM

10-2.5

. We are also proposing minimum requirements for a PM

10-2.5

monitoring network, including criteria for the number of FRM/FEM monitoring sites in each metropolitan area (which would vary from zero to five) and criteria for how monitors should be placed within an area. Closely linked to the placement criteria is a proposed test for the suitability of a PM

10-2.5

monitoring site for comparison with the PM

10-2.5

NAAQS. We are also proposing that speciation monitoring of PM

10-2.5

be required in some areas. These proposals appear in sections IV.B.2, IV.B.3, IV.B.5, and IV.B.6 (dealing with equivalent methods) and section IV.E.2 (dealing with number of monitors, their placement, and the use of data from them in comparisons to the NAAQS) of this preamble.

Class I equivalent methods have only minor deviations or modifications from the specified reference method. Class II equivalent methods include other filter-based, integrated, gravimetric-type methods similar to the specified reference method but with greater deviations than allowed for a Class I method. Class III equivalent methods include all candidate PM

2.5

and PM

10-2.5

methods not classified as Class I or Class II. We expect that most candidate Class III equivalent methods will be continuous or semi-continuous methods.

• We propose amendments to facilitate the wider use of continuous PM

2.5

monitors by revising performance-based FEM equivalence standards for continuous PM

2.5

monitors and allowing for approved regional methods (ARM) for continuous PM

2.5

mass monitors. Existing requirements for PM

2.5

Class I and Class II candidate equivalent methods would be revised, and new requirements for PM

2.5

Class III candidate equivalent methods would be added. The definition of a Class III equivalent method would be revised to allow for designation of continuous and semi-continuous ambient air monitoring methods for PM

2.5

. These proposals appear in sections IV.B.4, IV.B.5, and IV.B.6 (FEM equivalence standards) and in section IV.D.2 (approved regional methods) of this preamble.

• In association with the proposed requirements for new PM

10-2.5

stations and new NCore multipollutant stations, we propose to remove the existing requirements for certain numbers of State and local air FRM/FEM monitoring stations for CO, PM

, SO

, and NO

, and reduce them for Pb.

However, States would still need EPA approval to move or remove existing monitoring stations for these pollutants.

To expedite reviews and provide more certainty to State planning, a specific process and several substantive criteria are proposed to govern EPA approval actions. Also, the requirement that EPA approval be obtained at the Administrator level (rather than the Regional Administrator level) for the subset of these monitors historically designated as NAMS would be eliminated, and all changes would be reviewed by the Regional Administrator.

In addition, the requirements for monitoring of O

precursors under the PAMS program would be reduced by about 50 percent. These proposed changes allow PAMS monitoring to be more customized to local data needs rather than meeting so many specific requirements common to all subject O

nonattainment areas; the PAMS changes would also give States the flexibility to reduce the overall size of their PAMS programs—within limits—and to use the associated resources for other types of monitoring they consider more useful. Requirements for minimum numbers of O

and PM

2.5

monitors would be retained, with small adjustments. The overall impact of these changes would be to retain comprehensive monitoring networks for PM

2.5

and O

, and to reduce the number of SO

, CO, NO

, Pb, and PM

monitors in areas that do not have air quality problems for these pollutants. PM

2.5

and O

monitoring would be mostly unaffected because PM

2.5

and O

are current nonattainment challenges and comprehensive monitoring is needed to support efforts to attain the NAAQS. Many existing monitors for SO

, CO, NO

, Pb, and PM

can be discontinued because they are now well below the applicable NAAQS and the data from most of these monitors have low value for air quality management and research purposes. We expect reductions in the number of monitors for these pollutants nationally to be in the range of about 33 percent for SO

to about 90 percent for NO

This would free up resources to go beyond minimum requirements for O

, PM

2.5

, PM

10-2.5

, or other pollutants such as air toxics in areas where there are ongoing or new air quality management challenges. These proposed changes are described in sections IV.E.3 (number of PM

2.5

monitors), IV.E.4 (PM

monitors), IV.E.5 (number of O

monitors), IV.E.6 (number of CO, SO

, NO

, and Pb monitors), IV.E.7 (PAMS monitors), and IV.E.8 (process and criteria for moving or removing monitors) of this preamble.

Where the PM

annual and 24-hour NAAQS have both been revoked, the proposed rule does not require prior EPA approval for discontinuing a PM

monitor.

EPA Administrator approval would continue to be required for changes to some PM

2.5

speciation monitoring stations, to any required NCore multipollutant station, and to any PAMS station.

Detailed estimates of the current and expected future number of each type of monitor over the 3 years following promulgation are given in the supporting statement to the Information Collection Request for this action, available in the docket.

• We propose updated quality assurance (QA) requirements for all NAAQS pollutants, emphasizing the responsibility of each monitoring program for its data quality based on the use of data quality objectives for monitoring precision, data completeness, and bias. States would be required to provide for adequate, independent performance audits of FRM/FEM monitoring stations. We describe several options for how they could meet this audit responsibility. One way would be to agree to have appropriated State and Territorial Air Grant (STAG) funds retained by EPA to cover the cost of performing these audits; another option would be a partnership between State/local monitoring agencies (or independent subunits within one agency). The statistics for calculating precision and bias would also would be revised. Quality assurance requirements would be defined for PM

10-2.5

monitoring. See section IV.C of this preamble for details.

• We propose to revise the provisions regarding special purpose monitors (SPM) for all NAAQS pollutants. In certain restricted situations, data from SPM would not be usable for nonattainment designations. SPM that are FRM, FEM, or ARM monitors would be required to meet standard quality assurance requirements for their monitor type, and States would be required to report data from such SPM to the Air Quality System (AQS). See section IV.E.9 of this preamble for details.

• We propose to require that States conduct in-depth network assessments every 5 years. These assessments are intended to ensure that future gaps between data needs and monitoring operations are identified and filled in a timely manner. See section IV.E.11 of this preamble for specifics.

• We propose to move requirements for reporting certain operational data from PM samplers from 40 CFR part 50 to 40 CFR part 58, and to reduce the number of data elements required to be reported. This would put all similar data reporting requirements together in 40 CFR part 58 and allow them to apply to both FRM and FEM monitors. See section IV.G.1 of this preamble.

• We propose a new requirement for the reporting of PM

2.5

field blank data.

Only the data from field blanks which States are already taking into the field and weighing in their laboratories would be required to be reported under this proposal. Having the data from these field blanks available to the national monitoring community would help EPA and other researchers understand the relationship between the mass of PM that is sampled and weighed on a regular PM filter and the PM that is actually present in ambient air. See section IV.G.2 of this preamble or details.

Field blanks are filters which are handled in the field as much as possible like actual filters except that ambient air is not pumped through them, to help quantify contamination and sampling artifacts.

• We propose to require State or local agencies to submit annual data certification letters, by May 1 of each year, to certify that the ambient air concentration and QA data submitted to EPA's AQS for the previous year are complete and accurate. These letters are now required on July 1 of each year. See section IV.G.3 of this preamble.

• We propose to require States to archive PM

2.5

and PM

10-2.5

filters for one year (the current requirement is only for PM

2.5

filters).

See section IV.G.4 of this preamble.

A PM

10-2.5

“filter” from a FRM monitor would actually consist of the separate PM

and PM

2.5

filters. Some equivalent methods, if approved, could involve a single PM

10-2.5

filter. All filters from both types of monitors would be subject to the archiving requirement.

• We propose to increase the distance that ozone monitors should be placed downwind of roadways, to reduce the possibility that ozone readings will be artificially low due to ozone scavenging by NO emitted by vehicles on roadways. See section IV.F of this preamble.

C. When Would the Proposed Amendments Affect State and Local Governments, Tribes, and Other Stakeholders?

1. State and Local Governments

Only State governments, and those local governments that have been assigned responsibility for ambient air monitoring by their States, are subject to the mandatory requirements of 40 CFR part 58.

Throughout this preamble, “States” is meant to also refer to local governments that have been assigned responsibility for ambient air monitoring within their respective jurisdiction by their States. We also use “monitoring organization” to refer to States, local agencies, and/or Tribes conducting monitoring under or guided by the provisions of 40 CFR part 58.

The proposed compliance date for deployment of PM

10-2.5

monitors by States is January 1, 2009. A plan for this

deployment would be due January 1, 2008, unless an extension is granted to July 1, 2008. These plans would be subject to EPA approval at the Regional Office level.

State (or local) agencies would also be required to submit earlier annual data certification letters and make electronic reports of QA data to the AQS, starting May 1, 2009.

The proposed amendments require that State (or local) agencies fully implement the required NCore multipollutant sites by January 1, 2011 (more than 4 years after the expected date of promulgation of the amendments). A plan for this implementation, including site selection, would be due July 1, 2009.

Network assessments would be required every 5 years starting July 1, 2009.

State and local agencies would be required to comply with existing requirements in 40 CFR part 58 (including annual network review and data reporting), until the compliance date for each new requirement is reached.

Some provisions in the proposed amendments to 40 CFR part 58 (those that do not involve deployment of new monitoring stations or new types of data handling) would be effective as of the effective date of the final rule.

2. Tribes

Under the Tribal Authority Rule (TAR) (40 CFR part 49), which implements section 301(d) of the CAA, Tribes may elect to be treated in the same manner as a State in implementing sections of the CAA. However, the EPA determined in the TAR that it was inappropriate to treat Tribes in a manner similar to a State with regard to specific plan submittal and implementation deadlines for NAAQS-related requirements, including, but not limited to, such deadlines in CAA sections 110(a)(1), 172(a)(2), 182, 187, and 191. See 40 CFR 49.4(a). For example, an Indian tribe may choose, but is not required, to submit implementation plans for NAAQS related requirements, nor are they required to monitor. If a Tribe elects to do an implementation plan, the plan can contain program elements to address specific air quality problems in a partial program. The EPA will work with the Tribe to develop an appropriate schedule which meets the needs of each Tribe.

Indian tribes have the same rights and responsibilities as States under the CAA to implement elements of air quality programs as they deem necessary. Tribes can choose to engage in ambient air monitoring activities. In many cases, Indian tribes are required by EPA regions to institute strict quality assurance programs, utilize FRM or FEM when comparing their data to the NAAQS, and to insure that the data collected is qualitative and representative of their respective airsheds. For FRM and FEM monitors used for NAAQS attainment or nonattainment determinations, quality assurance requirements of 40 CFR part 58 must be followed and would be viewed by EPA as an indivisible element of a regulatory air quality monitoring program.

3. Other Stakeholders

Manufacturers of continuous PM

2.5

and PM

10-2.5

instruments would be able to apply for designation of their instruments as FEM as soon as the notice of final rulemaking is signed. The EPA is eager to receive such applications as soon as manufacturers can collect and analyze the necessary supporting data.

D. How Would EPA Implement the New Requirements?

After promulgation, we would implement the new requirements using several mechanisms. We expect to work with each State to develop the monitoring plans for their new PM

10-2.5

and NCore multipollutant monitoring stations. For example, we would negotiate the selection of required new monitoring sites (or new capabilities at existing sites) and their schedules for start up as well as plans to discontinue sites that were no longer needed. The EPA would negotiate with each State its annual grants for air quality management activities, including ambient monitoring work. We would negotiate grants that provide funding to meet minimum requirements and which have milestones for completion of necessary changes. Once States have established a new monitoring infrastructure to meet the new requirements, we would review State monitoring activities, submitted data, and plans for further changes on an annual basis.

The EPA's support for and participation in enhancing the national ambient air monitoring system to serve current and future air quality management and research needs will extend beyond ensuring that States meet the minimum requirements of the monitoring rules, including the proposed amendments. We will work with each State or local air monitoring agency to determine what affordable monitoring activities above minimum requirements would best meet the diverse needs of the individual air quality management program as well as the needs of other data users. In particular, we may negotiate with some States, and possibly with some Tribes, for the establishment and operation of some additional rural NCore multipollutant monitoring stations to complement the multipollutant stations that would be required by the proposed changes to the monitoring regulations. We also expect to work with the States, and possibly with some Tribes, to establish and operate more PM

10-2.5

speciation sites than the minimums that would be required by the proposed amendments. We expect to work with the States, and possibly with some Tribes, to establish and operate rural PM

10-2.5

mass concentration sites in less urbanized locations.

An important element of implementing the new requirements will be EPA's role in encouraging the development and application of Federal equivalent methods (FEM), in particular for continuous methods of measuring PM

2.5

and PM

10-2.5

. We have determined that continuous monitoring of PM

2.5

has many advantages over the filter-based Federal reference method. One of the proposed changes makes it more practical for manufacturers of continuous PM

2.5

instruments to obtain designation for them as FEM or approved regional methods. To ensure objectivity and sound science, EPA's Office of Research and Development would continue to review applications for FEM designations based on the criteria proposed today and would recommend approval or disapproval to the EPA Administrator.

We will also provide technical guidance documents and training opportunities for State, local, and Tribal monitoring staff to help them select, operate, and use the data from new types of monitoring equipment. We have already distributed a technical assistance document on the precursor gas monitors

that will be part of the multipollutant sites and we have conducted three training workshops on these monitors. Additional guidance will be developed and provided on some other types of monitors with which many State monitoring staff are currently unfamiliar, and on network design, site selection, quality assurance, and other topics. While Tribes are not to be subject to the requirements of the proposed monitoring amendments,

these technical resources will also be available to them directly from EPA and via grantees, such as the Institute for Tribal Environmental Professionals and the Tribal Air Monitoring Support Center.

Technical Assistance Document (TAD) for Precursor Gas Measurements in the NCore Multipollutant Monitoring Network. Version 4. U.S. Environmental Protection Agency. EPA-454/R-05-003. September 2005. Available at:

http://www.epa.gov/ttn/amtic/pretecdoc.html.

In partnership with States, we will also continue to plan and manage State technical assistance grants (STAG) to support the National Park Service's operation of the IMPROVE monitoring network, which provides important data for implementing both regional haze and PM

2.5

attainment programs.

Additional information on EPA/National Park Service IMPROVE (Interagency Monitoring of Protected Visual Environments) Visibility Program is available at:

http://www.epa.gov/ttn/amtic/visdata.html.

We will also continue to operate the Clean Air Status and Trends Network (CASTNET), which monitors for O

, PM, and chemical components of PM in rural areas across the nation.

We are in the process of revising CASTNET to upgrade its monitoring capabilities to allow it to provide even more useful data to multiple data users. We expect that about 20 CASTNET sites will have new capabilities at least equivalent to the capabilities envisioned for NCore multipollutant sites. Those sites would reduce the number of, and complement, rural multipollutant sites funded with limited State/local grant funds.

Additional information on CASTNET is available at:

http://www.epa.gov/castnet/.

We recognize that some air quality management issues require ambient concentration and deposition data that cannot be provided by the types of monitoring required by the proposed monitoring amendments and other activities addressed in today's proposal. These issues include near-roadway exposures to emissions from motor vehicles and mercury deposition. We are actively researching these issues and developing plans for monitoring programs to address them, but these issues are outside the scope of this proposal.

III. Background

A. What Is the Role of Ambient Air Monitoring in Air Quality Management?

Ambient air monitoring systems are a critical part of the nation's air quality management program infrastructure. We use the ambient air monitoring data for a wide variety of purposes as part of an iterative process in managing air quality. This iterative process involves a continuum of setting standards and objectives, designing and implementing control strategies, assessing the results of those control strategies, and measuring progress. The data have many uses throughout this system, such as: Determining compliance with the National Ambient Air Quality Standards (NAAQS); characterizing air quality status and trends; estimating health risks and ecosystem impacts; developing and evaluating emissions control strategies; and measuring overall progress for the air pollution control program. Ambient air monitoring data provide accountability for control strategy reductions by tracking long-term trends of criteria and noncriteria pollutants and their precursors. The data also form the basis for air quality forecasting and other public air quality reports.

More detailed ambient monitoring data are needed to meet current and future program and research needs. The data collected by State and local agencies under the proposed monitoring amendments would:

• Provide more timely Air Quality Index reporting to the public by supporting continuous particle measurements needed for AIRNow air quality forecasting and other public reporting mechanisms;

• Improve the development of emissions control strategies through more effective air quality model evaluation and other observational methods; and

• Support long-term health assessments that contribute to ongoing reviews of the NAAQS and other scientific studies ranging across technological, health, and atmospheric process disciplines.

B. What Is the History of Ambient Air Monitoring?

1. Statutory Authority

The EPA rules for ambient air monitoring are authorized under sections 110, 301(a), and 319 of the Clean Air Act (CAA). Section 110(a)(2)(B) of the CAA requires that each State implementation plan (SIP) provide for the establishment and operation of devices, methods, systems, and procedures needed to monitor, compile, and analyze data on ambient air quality and for the reporting of air quality data to EPA. Section 301(a) of the CAA authorizes EPA to develop regulations needed to carry out the Agency's mission and establishes rulemaking requirements. Uniform criteria to be followed when measuring air quality and provisions for daily air pollution index reporting are required by CAA section 319.

2. Ambient Air Monitoring Regulations

The EPA's procedures for determining and designating reference and equivalent methods (40 CFR part 53) have been in place since 1975 (40 FR 7049, February 18, 1975). Reference methods for criteria pollutants provide uniform, reproducible measurements of concentrations in the ambient air. Equivalent methods allow for the introduction of new and innovative technologies for the same purpose, provided the technologies produce measurements comparable to reference methods under a variety of monitoring conditions.

Subpart A of 40 CFR part 53 (General Provisions) establishes definitions; general requirements for designation of Federal reference methods (FRM) and Federal equivalent methods (FEM); procedures for submitting, processing, and approving applications; and associated provisions. The general requirements identify the applicable requirements or tests that a candidate method must meet to be approved as a FRM or FEM. All manual or automated methods must meet the applicable requirements in 40 CFR part 53, subpart C (Procedures for Determining Comparability Between Candidate Methods and Reference Methods). Automated equivalent methods for pollutants other than PM

or PM

2.5

also must meet the requirements in 40 CFR part 53, subpart B (Procedures for Testing Performance Characteristics of Automated Methods for SO

, CO, O

, and NO

). A manual sampler or automated method for PM

, Class I equivalent method for PM

2.5

, or Class II equivalent method for PM

2.5

also must meet the requirements in 40 CFR part 53, subpart D (Procedures for Testing Performance Characteristics of Methods for PM

), subpart E (Procedures for Testing Physical (Design) and Performance Characteristics of Reference Methods and Class I Equivalent Methods for PM

2.5

), or subpart F (Procedures for Testing Performance Characteristics of Class II Equivalent Methods for PM

2.5

), as applicable. The existing rule adopts a case-by-case approach for PM

2.5

Class III candidate equivalent methods. The regulations in 40 CFR part 53 have been amended several times since 1975 to reflect the addition of new and revised reference methods and advances in monitoring methods and technologies for criteria pollutants.

In 1979 (44 FR 27558, May 10, 1979), EPA issued the first regulations for ambient air quality surveillance (40 CFR part 58) for all pollutants subject to NAAQS. Within 40 CFR part 58, subpart A (General Provisions) establishes definitions, and subpart B (Monitoring Criteria) sets requirements for quality assurance, methods, siting, operating

schedules, and special purpose monitors. Subpart C (State and Local Air Monitoring Stations), subpart D (National Air Monitoring Stations), and subpart E (Photochemical Assessment Monitoring Stations) generally define the current monitoring networks. Appendices A through G to 40 CFR part 58 contain more detailed requirements on quality assurance; monitoring methods, network design, and siting criteria; and air quality reporting. Subpart F (Air Quality Index Reporting), subpart G (Federal Monitoring), and appendices F and G to 40 CFR part 58 define annual and daily reporting requirements.

Most of the major amendments to the monitoring regulations made after 1979 coincide with the NAAQS revisions and include the addition of provisions for PM

(52 FR 24740, July 1, 1987) and PM

2.5

(62 FR 38833, July 18, 1997). Photochemical assessment monitoring stations (PAMS) were established in 1993 to monitor ozone and visibility (58 FR 8468, February 12, 1993).

3. Monitoring Networks

More than 5,500 monitors at about 3,000 sites in the State and local air monitoring stations (SLAMS) and national air monitoring stations (NAMS) networks comprise the majority of monitors measuring criteria pollutants using FRM or FEM for direct comparison to the NAAQS. The NAMS are a subset of SLAMS that are designated as national trends sites. The PM

2.5

network consists of ambient air monitoring sites that make mass or chemical speciation measurements. Within the PM

2.5

network operated by State and local agencies, there are approximately 1,200 FRM filter-based samplers and about 450 continuous monitors for mass measurements. Chemical speciation measurements are made at 54 “Speciation Trends Network” sites that are intended to remain in operation indefinitely and about 200 other, potentially less permanent sites used to support SIP development and other monitoring objectives. These stations collect aerosol samples and analyze the filters for trace elements, major ions, and carbon fractions.

Ambient air monitors in the PAMS network measure ozone precursors at 109 stations in 25 serious, severe, or extreme ozone nonattainment areas. The PAMS monitors use near-research-grade measurement technologies to produce continuous data for more than 50 volatile organic compounds during summer ozone seasons.

In addition to the NAMS/SLAMS/PAMS sites, there are approximately 310 ambient air toxics monitoring sites, the majority of which are Federally funded and report data to EPA's Air Quality System (AQS).

Ambient air monitoring stations also are operated by Indian Tribes. Thirty-one Tribes are currently making data from 119 individual monitors available to EPA and others. Approximately 73 Tribal sites monitor for PM

and PM

2.5

, and about 16 monitor for ozone.

The Clean Air Status and Trends Network (CASTNET) is cooperatively operated and funded by EPA with the National Park Service. The EPA's Office of Air and Radiation operates a majority of the monitoring stations with contractor support; however, the National Park Service operates approximately 30 stations in cooperation with EPA. It the nation's primary source for data on dry acidic deposition and rural, ground-level ozone. Operating since 1987, CASTNET is used in conjunction with other national monitoring networks to provide information for evaluating the effectiveness of national emission control strategies. CASTNET consists of over 80 sites across the eastern and western U.S. The longest data records are primarily at eastern sites. CASTNET provides atmospheric data on the dry deposition component of total acid deposition, ground-level ozone and other forms of atmospheric pollution. More information is available from the CASTNET program Web site

http://www.epa.gov/castnet/.

The EPA is also one of many sponsors of the National Atmospheric Deposition Program/National Trends Network. The National Atmospheric Deposition Program/National Trends Network (NADP/NTN) is a nationwide network of precipitation monitoring stations. The NADP/NTN has over 200 stations spanning the continental U.S., Alaska, and Puerto Rico, and the Virgin Islands. The purpose of the network is to collect data on the chemistry of precipitation for monitoring of geographical and temporal long-term trends. While distinct from ambient air monitoring, precipitation monitoring is related in that it shares same of the same objectives, including tracking the effects of emission reduction programs. More information on NADP is available at its Internet Web site,

http://nadp.sws.uiuc.edu/.

The EPA is a major funding sponsor of the Interagency Monitoring of Protected Visual Environments (IMPROVE) program. IMPROVE is a cooperative measurement effort governed by a steering committee composed of representatives from EPA, National Park Service, other Federal agencies, and Regional-State organizations. A total of 110 monitoring stations in Class I visibility areas have particulate matter samplers to measure speciated PM

2.5

and PM

mass. Select stations also deploy transmissometer and nephelometers to measure light extinction and scattering respectively, as well as automatic camera systems. Some IMPROVE stations include an O

monitor. The objectives of IMPROVE are: (1) To establish current visibility and aerosol conditions in mandatory Class I areas; (2) to identify chemical species and emission sources responsible for existing man-made visibility impairment; (3) to document long-term trends for assessing progress towards the national visibility goal; (4) and with the enactment of the Regional Haze Rule, to provide regional haze monitoring representing all visibility-protected Federal Class I areas where practical. The IMPROVE stations provide very useful information on regional-scale particulate matter concentrations which can help States and EPA attribute urban concentrations of PM

2.5

to local versus regional sources and to types of sources. More information on the IMPROVE program is available on its Internet Web site,

http://vista.cira.colostate.edu/improve/.

4. Data Storage and Dissemination Systems

a. Air Quality System. The AQS stores data collected from over 10,000 monitors, about 5,500 of which are currently active for criteria pollutants. The AQS also contains meteorological data, air toxics data, descriptive information about each monitoring station (including its geographic location and its operator), and data quality assurance/quality control information. The EPA and other AQS users rely upon the system data to assess air quality, assist in attainment and non-attainment designations, evaluate SIP, perform modeling for permit review analysis, and other air quality management functions. The AQS information is also used to prepare reports for Congress as mandated by the CAA. The AQS Web site address is:

http://www.epa.gov/ttn/airs/airsaqs/index.htm.

b. AIRNow. AIRNow is a cross-government Web site (

http://airnow.gov/

) that provides the public with easy access to national air quality information. The Web site offers a daily forecast of conditions and associated health effects, known as the Air Quality Index (AQI), as well as real-time conditions for more than 300 cities across country. The AQI focuses on health effects that may occur within a

few hours or days after breathing polluted air. The EPA calculates the AQI for ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The AIRNow Web site displays nationwide and regional real-time PM

2.5

and ozone air quality maps for 48 States and parts of Canada. The air quality data used in these maps and to generate forecasts are collected using either FRM, FEM, or techniques approved by State monitoring agencies.

c. Other existing data systems. Other existing data systems for ambient air quality-related data include EPA's National Emission Inventory (NEI) and AirData. The NEI database at

http://www.epa.gov/ttn/chief/eiinformation.html

provides information about sources that emit criteria air pollutants and estimates of annual air pollutant emissions from point, nonpoint, and mobile sources. The EPA compiles the NEI database from emissions inventories compiled by State and local environmental agencies based on State reporting requirements in 40 CFR part 51, agency rulemaking databases, and the Toxic Release Inventory data from industry. The EPA updates the NEI database every 3 years.

The AirData Web site at

http://www.epa.gov/air/data/

provides annual summaries of ambient monitoring and emissions inventory data from the AQS and NEI. The database includes emission estimates from all 50 States plus the District of Columbia, Puerto Rico, and the U.S. Virgin Islands, and provides data in a variety of formats. Other web-based data systems related to ambient air concentration data include VIEWS (

http://vista.cira.colostate.edu/views/

) to support analysis of visibility-related data from the IMPROVE network, and Web sites to support analysis of CASTNET (

http://www.epa.gov/castnet/data.html

) and NADP (

http://nadp.sws.uiuc.edu/

) data sets.

5. EPA Funding

The EPA has historically funded part of the cost of installation and operation of monitors to meet Federal monitoring requirements to defray costs for State, local, and tribal governments. Sections 103 and 105 of the CAA allow EPA to provide grant funding for programs for preventing and controlling air pollution and for some research and development efforts. States must apply for section 103 grants and State agencies must provide nonfederal matching funds for section 105 grants.

C. What Revisions to the National Ambient Air Quality Standards for Particulate Matter Also Are Proposed Today?

1. PM

2.5

: Primary Standards, Secondary Standard, and Federal Reference Method

Elsewhere in this

Federal Register

, we are proposing revisions to the National Ambient Air Quality Standards (NAAQS) for particulate matter (PM). Under the proposal, the 24-hour primary standard for PM

2.5

would be reduced from the current level of 65 micrograms per cubic meter (μg/m

) to 35 μg/m

(based on the three-year average of the annual 98th percentile concentrations). We also are proposing to retain the level of the current annual PM

2.5

standard at 15 μg/m

and to add additional constraints to the use of spatial averaging to demonstrate compliance with that standard. The EPA is also proposing to revise the current secondary standards for PM

2.5

by making them identical to the suite of proposed primary standards.

The NAAQS proposal would also make several changes to the Federal reference method (FRM) for PM

2.5

in 40 CFR part 50, appendix L. These changes would improve the operation and maintenance aspects of the PM

2.5

monitoring network. Specifically, we are proposing to adopt the “very sharp cut cyclone” (VSCC) as an approved second-stage impactor. The performance of the VSSC separator is equivalent to that of the WINS (Well Impactor Ninety Six) impactor currently specified in the proposed reference method and has a considerably longer service interval. We also are proposing to require dioctyl sebacate as an alternative oil approved for use in the WINS, to extend the maximum allowed time to recover filters from samplers, and to modify the filter transport temperature and post-sampling time requirements for final laboratory analysis.

2. PM

10-2.5

: Primary Standard, Secondary Standard, and Federal Reference Method

The NAAQS proposal would also revise the current 24-hour primary standard for PM

by replacing the indicator with a PM

10-2.5

indicator. The proposed PM

10-2.5

indicator is qualified so as to include any ambient mix of PM

10-2.5

that is dominated by resuspended dust from high-density traffic on paved roads and PM generated by industrial sources and construction sources, and exclude any ambient mix of PM

10-2.5

that is dominated by rural windblown dust and soils and PM generated by agricultural and mining sources. This standard shall not require control of agricultural sources and mining sources. The proposed level of the standard is 70 μg/m

, based on the three-year average of the annual 98th percentile concentrations.

Accordingly, the proposed revisions to the NAAQS include a new FRM for measuring PM

10-2.5

(Reference Method for the Determination of Coarse Particulate Matter as PM

10-2.5

in the Atmosphere) to be codified in a new appendix O to 40 CFR part 50. The proposed FRM is based on the combination of two low-volume, filter-based methods, one for measuring PM

and the other for measuring PM

2.5

, and determines the PM

10-2.5

measurement by subtracting the PM

2.5

measurement from the concurrent PM

measurement. The PM

2.5

measurement method is identical to the PM

2.5

FRM currently specified in 40 CFR part 50, appendix L (Reference Method for the Determination of Fine Particulate Matter as PM

2.5

in the Atmosphere), with the proposed changes described above. The PM

measurement method is very similar and utilizes a sampler that is the same as the PM

2.5

sampler, except that it has no PM

2.5

particle size separator downstream of the PM

separator. Thus, this proposed PM

10-2.5

FRM is based on the same aerodynamic particle size separation and filter-based, gravimetric technology that is also the basis of the FRM for PM

2.5

(with the proposed changes described above).

3. Data Handling Procedures for PM

2.5

and PM

10-2.5

In the PM NAAQS proposal published elsewhere in today's

Federal Register

, EPA is also proposing to revise the conditions under which spatial averaging of the annual primary PM

2.5

NAAQS would be permitted. We also propose to move the criteria for determining if spatial averaging is acceptable from section 2.8.1.6.1 of appendix D to 40 CFR part 58 to appendix N of 40 CFR part 50 (Interpretation of the National Ambient Air Quality Standards for PM

2.5

). We also propose to add a new appendix P to 40 CFR part 50 (Interpretation of the National Ambient Air Quality Standards for PM

10-2.5

) to provide data handling procedures for PM

10-2.5

4. Revocation of National Ambient Air Quality Standards for PM

In the PM NAAQS proposal, we are proposing to revoke the current annual PM

standard immediately should we finalize the primary standards for PM

10-2.5

proposed in that notice. Further, we propose that the current 24-hour PM

standard be revoked in all

areas except for 20 areas listed in section III of the NAAQS proposal preamble.

D. How Do the Monitoring Data Apply to Attainment or Nonattainment Designations and Findings?

The criteria for determining when it is appropriate to compare ambient monitoring data from a specific monitor and period to a National Ambient Air Quality Standard (NAAQS) is an important element of the air quality management system because it can identify what geographic areas have air quality problems and may be designated as nonattainment.

Later sections of this preamble, discussing the proposed monitoring requirements for the proposed PM

10-2.5

NAAQS and the proposed provisions for special purpose monitors (SPM), discuss the use of monitoring data for attainment or nonattainment designations. We are also proposing a change related to the required spacing between ozone (O

) monitors and roadways. Finally, we are proposing changes to some quality assurance requirements. This section of the preamble provides background information on current EPA policy and regulations in order to facilitate informed public comment on these aspects of today's proposal.

There are some preconditions to use of data from an ambient monitor for comparison to an NAAQS that generally apply to the current NAAQS for O

, PM

2.5

, CO, SO

, NO

, and Pb, with a few exceptions and/or the opportunity for waiver by EPA.

These include the following:

Monitors that have received waivers are eligible for comparison to their respective NAAQS.

• The monitoring site must represent ambient air, as defined in 40 CFR 50.1 (

i.e.

, “that portion of the atmosphere, external to buildings, to which the general public has access”). In practical terms, this means that data from monitoring sites within the boundaries of a privately-owned facility to which public access is restricted, for example, a storage yard of a factory, are not eligible for comparison to the NAAQS. (On occasion, EPA has relied on data from such sites when the air sampled is ambient air, even though the monitor may be sited on a facility to which public access is restricted (

e.g.

, the monitor is very close to a fence line and is monitoring the conditions that are present in the adjacent publicly accessible property.) Data from a monitor in ambient air as so defined can be compared to the NAAQS even if members of the public infrequently come near the monitor's location (

e.g.

, O

monitors that are located on the ground on high elevation mountain sites). However, data from monitors located high above standing/walking ground level, such as on a high roof or tower, are not eligible for comparison to an NAAQS. It should be noted that although monitors are often sited with the intention to represent an area of a certain geographic scale, in general, a monitor need not be representative of the ambient air quality across an area of any specific size to be eligible for comparison to most NAAQS. However, as described in section IV.E.2 of this preamble, the current annual PM

2.5

NAAQS is an exception, and the proposed 24-hour PM

10-2.5

NAAQS would be an exception. (See also the item in this list regarding proximity of O

and CO monitors to roadways.)

• The monitor must use a Federal reference method (FRM) or Federal equivalent method (FEM).

• The monitoring data must be technically valid so as to be truly representative of the actual air quality at its location during the sampline period, subject to the normal limitations of the FRM or FEM when properly operating. Generally, this means that the monitor's operation and subsequent sample handling and laboratory analysis, if applicable, must observe minimum quality assurance (QA) procedures, as set forth in 40 CFR 58.10 and 40 CFR part 58, appendices A and B (consolidated into a single appendix A in the proposed amendments), to guard against equipment malfunction, miscalibration, drift, or operator error. When States document that these procedures have been followed, the data are presumed to be valid although specific evidence of instrument faults or procedural errors can cause EPA to disregard data from particular periods. When documentation on whether these specific procedures have been followed is not available to EPA, as may be the case if a State has not submitted QA data to the Air Quality System (AQS) or if the monitoring was performed by a non-State organization not subject to the QA requirements in 40 CFR part 58, appendices A and B, the validity of data is considered on a case-by-case basis if the issue is raised by EPA, the State, or another party during an NAAQS designation process.

• The monitoring probe inlet (or open path, for open path monitors) must meet certain requirements for distance from adjacent roadways. This is a feature of the current monitoring requirements in 40 CFR part 58, appendix E (Probe and Monitoring Path Siting Criteria for Ambient Air Quality Monitoring) and the proposed amendments.

Ozone monitors too close to a roadway may be measuring air in which O

has been scavenged by nitric oxide (NO). Carbon monoxide and NO

monitors that are too close to a roadway can measure concentrations that do not represent likely human exposures of any significant frequency or duration. Requirements regarding spacing from roadways can be waived if no other suitable site is available.

Minimum separation distance requirements in the current rule apply to O

, NO

, CO, Pb (for stations designed to assess concentrations from mobile sources) and PM (PM

and PM

2.5

). Under the proposed amendments, minimum separation distance requirements would apply to O

, oxides of nitrogen (NO, NO

, NO

), CO, PM (PM

, PM

2.5

, PM

2.5

) and Pb for stations designed to assess concentrations from stationary or mobile sources.

• The monitoring probe inlet (or open path, for open path monitors) must meet certain minimum distance limits for proximity to nearby obstructions, such as walls of buildings.

• The probe height above the surface on which the public would stand or walk nearby must be within a certain range so that the air it samples is reasonably representative of what the public breathes when near the monitor. This requirement can be waived for practicality reasons.

• The monitoring data must be sufficiently complete according to requirements defined for each NAAQS in 40 CFR part 50, appendices H, I, K, and N (a new appendix P proposed elsewhere in today's

Federal Register

would add completeness requirements for PM

10-2.5

In addition to these generally applicable preconditions or restrictions, the current requirements of 40 CFR part 58 contain the following special provisions for PM

2.5

Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone; Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone; Interpretation of the National Ambient Air Quality Standards for PM

; Interpretation of the National Ambient Air Quality Standards for PM

2.5

; and Interpretation of the National Ambient Air Quality Standards for PM

10-2.5

, respectively.

• Data from a PM

2.5

monitor can be compared to the annual or 24-hour PM

2.5

NAAQS only if its location is “population-oriented.”

“Population-

oriented monitoring or sites” is described in 40 CFR 50.1 as applying to residential areas, commercial areas, recreational areas, industrial areas, and other areas where a substantial number of people may spend a significant fraction of their day.

Section 2.8.1.2.3 of appendix D to 40 CFR part 58 states that PM

2.5

data from state or local air monitoring systems (SLAMS) and special purpose monitors (SPM) that are “* * * representative of relatively unique population-oriented microscale or localized hot spot or unique population-oriented middle scale impact sites are only eligible for comparison to the 24-hour PM

2.5

NAAQS.” However, under certain circumstances, the Regional Administrator may approve population-oriented microscale or middlescale impact sites for comparison to the annual NAAQS.

• Data from a PM

2.5

monitor that is located in a “microscale” location, meaning it is influenced by a nearby emissions source while locations somewhat further away would be much less influenced, can be compared to the annual PM

2.5

NAAQS only if its location is representative of many other locations in the surrounding urban area, such that significant numbers of people can be expected to have similar PM

2.5

concentration exposures as people living, working, or visiting the location of the monitor in question (section 2.8.1.2.3 of appendix D to 40 CFR part 58).

• Under certain conditions, a State may, with the approval of EPA, average data from specified monitors for purposes of comparing the data to the annual PM

2.5

NAAQS. To be approved for spatial averaging, as it is known, monitors must meet certain requirements for relative location and measure concentrations as specified in section 2.8 of appendix D to 40 CFR part 58 (section 4.7.5 of proposed appendix D to 40 CFR part 58).

Changes to the requirements for spatial averaging are proposed elsewhere in this

Federal Register

• The first two complete calendar years of data from an SPM for PM

2.5

may be excluded from comparisons to the PM

2.5

NAAQS, but only if the monitor is not continued beyond those 2 years (section 2.8.1.2.2 of appendix D to 40 CFR part 58).

The first three of these four special provisions for PM

2.5

are tied to the reliance by EPA on community epidemiology studies in setting the form and levels of the annual and 24-hour PM

2.5

NAAQS. In simple terms, EPA determined that the levels of these NAAQS would be appropriately protective of public health based on a presumption that NAAQS compliance determinations would be made using data only from monitors that represented concentrations to which a large portion of the population would be exposed, even though some individuals would have higher or lower exposures.

Finally, EPA has policies addressing situations in which natural events and exceptional events have, or may have, influenced monitored concentrations. Under these policies, States may make the case that data from an otherwise eligible monitor from a specific period should not be used in comparisons to the NAAQS. We expect to revise these policies and codify them in 40 CFR part 50 in a separate rulemaking.

These policies on natural and exceptional events will be discussed in the preamble to the Natural and Exceptional Events rule to be published in the near future.

IV. Proposed Monitoring Amendments

A. What Are the Proposed Terminology Changes?

In 40 CFR 58.1, we propose to replace the definition of “National Air Monitoring Stations (NAMS)” with a new definition for the “National Core (NCore)” network. The NCore designation

structure would be based on a tiered system of measurements including complex research-oriented stations,

multipollutant stations equipped to support a better understanding of ozone, particulate matter (PM), and PM precursors, and sites with as few as one measured pollutant identified as State and Local Air Monitoring Stations (SLAMS) that are primarily intended to support compliance with the National Ambient Air Quality Standards (NAAQS).

Because the terms, SLAMS and NAMS, are used extensively through the current rules, this terminology change results in numerous changes. For clarity, we are publishing the entire text of 40 CFR part 58, appendix D (Network Design Criteria for Ambient Air Quality Monitoring).

The NCore research grade station designation is defined in the proposed amendments in anticipation that these stations will be initiated at some time in the future. We are not proposing to require (or to fund) NCore research grade stations in this notice.

We are proposing to add a definition for the term, “approved regional methods” (ARM) to 40 CFR 58.1. This term refers to alternative PM

2.5

methods that have been approved by EPA for use specifically within a State, local, or tribal air monitoring network for purposes of comparison to the NAAQS and to meet other monitoring objectives, but which may not have been approved as Federal equivalent methods (FEM) for nationwide use. The proposed testing criteria for approval of ARM are specified in 40 CFR part 58, appendix C (Ambient Air Monitoring Methodology).

In 40 CFR 53.1, we are proposing to revise the definition of the term “Class III equivalent method” to apply only to continuous or semi-continuous methods having 1-hour (or less) measurement resolution. The revised definition would read:

* * * an equivalent method for PM

2.5

or PM

10-2.5

that is an analyzer capable of providing PM

2.5

or PM

10-2.5

ambient air measurements representative of 1-hour or less integrated PM

2.5

or PM

10-2.5

concentrations as well as 24-hour measurements determined as, or equivalent to, the mean of 24 consecutive 1-hour measurements.

Restricting the Class III definition as proposed would offer a technical advantage by allowing the establishment of more tolerant minimum performance limits than would be necessary if non-continuous methods were included.

We are also proposing to add a definition of the term “PM

10c

” to 40 CFR 53.1. This term refers to PM

measurements obtained with a specially-approved sampler that meets more demanding performance specifications than high-volume PM

samplers described in 40 CFR part 50, appendix J (Reference Method for the Determination of Particulate Matter as PM

in the Atmosphere). Measurements obtained with PM

10c

samplers are intended to be paired with PM

2.5

measurements from Federal reference method (FRM) samplers as part of the difference measurement (PM

10-2.5

equals PM

10c

minus PM

2.5

) specified in the proposed appendix O to 40 CFR part 50 (Reference Method for the Determination of Coarse Particulate Matter as PM

10-2.5

in the Atmosphere) published elsewhere in today's

Federal Register

B. What Are the Proposed Requirements for Approval of Reference or Equivalent Methods?

The provisions of 40 CFR part 50 and related appendices define certain ambient air monitoring methods (or methodology) as reference methods for the purpose of determining attainment of the National Ambient Air Quality Standards (NAAQS). Under 40 CFR part 53, EPA designates specific commercial instruments or other versions of methods as Federal reference methods (FRM). Furthermore, to foster the development of improved alternative air monitoring methods, EPA also designates alternative methods that are shown to have comparable performance as Federal equivalent methods (FEM). Explicit performance tests, performance standards, and other requirements for designation of both FRM and FEM are provided in 40 CFR part 53 for each of the criteria pollutants. Only designated reference or equivalent methods may be used in the States' air surveillance monitoring networks. A list of all methods that EPA has designated as either FRM or FEM for all criteria pollutants is available at

www.epa.gov/ttn/amtic/criteria.html.

Elsewhere in this

Federal Register

, EPA is proposing a new reference method (40 CFR part 50, appendix O) for the measurement of coarse

particulate matter (PM) in the ambient air. Concurrent with the proposal of this new reference method, EPA is also proposing amendments to 40 CFR part 53 to extend the designation provisions to methods for PM

10-2.5

. These proposed amendments would set forth explicit tests, performance standards, and other requirements for designation of specific commercial samplers, sampler configurations, or analyzers as either FRM or FEM for PM

10-2.5

, as appropriate.

The EPA recognizes that the PM

10-2.5

reference method, while providing a good standard of performance for comparison to other methods, is not itself optimal for routine use in large PM

10-2.5

monitoring networks. Accordingly, EPA is specifically encouraging the development of alternative methods (and particularly continuous monitoring methods) for PM

10-2.5

by focusing on the explicit test and qualification requirements necessary for designation of such types of methods as equivalent methods for PM

10-2.5

. Virtual-impactor technology provides a more direct measurement of PM

10-2.5

and can provide an integrated PM

10-2.5

sample filter for chemical species analyses that can be important in the development of PM

10-2.5

control strategies. Continuous (or semi-continuous) methods for PM

10-2.5

typically provide significant operational advantages over 24-hour integrated monitoring methods, such as a self-contained automatic measurement process for output of nearly real-time measurements, reduced on-site service and off-site filter analysis and support requirements, and measurement resolution of one-hour or less. In addition, corresponding provisions for considering the designation of continuous or semi-continuous equivalent methods for PM

2.5

are also being proposed, since such provisions are similar to those for PM

10-2.5

and are not currently included in 40 CFR part 53. The nature of the proposed new provisions for automated methods, which can accommodate a wide range of potential PM

10-2.5

or PM

2.5

measurement technologies, is based primarily on ambient air testing at diverse monitoring sites to demonstrate that the level of comparability to collocated reference method measurements is adequate to meet established data quality objectives. Furthermore, some existing requirements for designation of alternative, non-continuous methods for PM

2.5

would be modified to be more consistent with the more advanced new requirements for non-continuous methods for PM

10-2.5

and for continuous methods.

For this reason, we view our proposal as consistent with the objectives of section 6102 of the Transportation Equity Act for the 21st Century. See section VI.5 of the preamble for the proposed amendments to the National Ambient Air Quality Standards for particulate matter published elsewhere in this

Federal Register

1. Proposed Requirements for Candidate Reference Methods for PM

10-2.5

Because of the nearly complete similarity between the specifications of the proposed PM

10-2.5

reference method and the existing PM

2.5

reference method, the proposed designation requirements for PM

10-2.5

reference methods are essentially the same as those for PM

2.5

reference methods.

In fact, EPA proposes that a PM

10-2.5

sampler pair consisting of samplers that have been shown to meet the PM

2.5

reference method requirements (except for the PM

2.5

particle size separator in the case of the PM

10c

sampler) may be designated as a PM

10-2.5

reference method without further testing.

The proposed PM

10-2.5

reference method specifies a pair of samplers consisting of a conventional PM

2.5

sampler and a special PM

sampler. The PM

2.5

sampler must meet all requirements for a PM

2.5

reference method in 40 CFR part 50, appendix L. However, the PM

sampler required by the proposed method is not a conventional PM

sampler as described in 40 CFR part 50, appendix J; rather, it is a sampler specified to be identical to the PM

2.5

sampler of the pair, except that the PM

2.5

particle size separator is removed. This special PM

sampler is identified as a “PM

10c

” sampler to differentiate it from conventional PM

samplers that meet the lesser requirements of 40 CFR part 50, appendix J.

2. Proposed Requirements for Candidate Equivalent Methods for PM

10-2.5

As noted, EPA will strive to encourage the development of improved alternative air monitoring methods by providing for their designation as equivalent methods. But developing suitable qualification requirements for equivalent methods for PM

10-2.5

is complicated by the complex physical and chemical nature of PM, the definition of PM

10-2.5

that to some extent incorporates the nature of the measurement technique defined in the reference method, and a wide variety of alternative PM

2.5

measurement techniques that are or may become available or may be technically feasible. Alternative methods must be shown to provide concentration measurements closely comparable to those obtained with reference methods. Thus, the requirements established for designation of equivalent methods must identify candidate methods that can achieve that goal, while also having reasonable testing protocols that are not so extensive or burdensome as to effectively inhibit approval of adequate and suitable improved or alternative candidate methods.

In light of these constraints, EPA previously defined three classes of PM

2.5

candidate equivalent methods in 40 CFR part 53 with progressively greater equivalent method qualification burdens. Class I equivalent methods are limited to methods having “* * * only minor deviations or modifications * * *” from the specified reference method and have the most modest requirements for equivalent method designation (in addition to the applicable reference method designation requirements). Class II equivalent methods include other filter-based, integrated, gravimetric-type methods similar to the reference method, but with greater deviation than allowed for Class I. Class III equivalent methods include all other candidate PM

2.5

methods not classified as Class I or II. The proposed amendments would extend the definition of Class I, Class II, and Class III candidate equivalent methods to PM

10-2.5

Because Class I equivalent methods for PM

10-2.5

differ only very modestly from PM

10-2.5

reference methods, designation requirements would also be very similar. The EPA is proposing that PM

10-2.5

Class I equivalent methods be designated if the samplers of the PM

10-2.5

sampler pair are shown to meet all requirements for either PM

2.5

reference methods or Class I equivalent methods. As for PM

10-2.5

reference methods, no further tests would be required.

One type of Class II equivalent sampler for PM

10-2.5

could be based on virtual impactor technology, which is designed to separate coarse mode aerosols from fine mode aerosols. The resulting size-segregated filter samples could be of great importance to State, local, and tribal agencies to obtain PM

10-2.5

sample filters for chemical speciation analyses. Class II methods, having greater deviation from the reference method, would have more extensive designation requirements. These methods still typically have many similarities to the reference method, and therefore, many of the reference method designation requirements would apply to Class II candidate equivalent methods. Generally, these methods must be subject to extensive laboratory and wind-tunnel tests to determine their performance relative to the performance of the reference method. However, for methods that have only one substantial difference from the reference method specifications (such as a virtual impactor particle-size separator), only those laboratory tests pertaining to the

performance of the deviating component would be required. Further, for methods that have more deviation from the reference method specifications, the proposed requirements would provide an option to substitute more extensive field comparison tests for some or all of the extensive laboratory tests that would otherwise be required. Since such additional field tests would be similar to field test requirements proposed for PM

10-2.5

methods, concurrent field testing for PM

2.5

and PM

10-2.5

methods could be carried out. Concurrent testing would substantially reduce the testing burden for candidate equivalent methods that measure both PM

2.5

and PM

10-2.5

(such as a dichotomous, virtual impactor sampler), which could be tested simultaneously for designation as an equivalent method for both PM indicators.

3. Continuous Methods for PM

10-2.5

The EPA recognizes that filter-based measurement methods for either PM

2.5

or PM

10-2.5

that require manual gravimetric analysis, as embodied in the corresponding reference methods, as well as Class I and Class II equivalent methods, are by nature very labor intensive. They are expensive to operate in routine monitoring networks and can generally provide only delayed reporting of multiple-hour integrated measurements. Self-contained, continuous-type automated monitoring methods (analyzers), such as those that are commonly used for monitoring various gaseous pollutants, overcome many of these shortcomings. Various types of continuous (or nearly continuous) analyzers have been developed or are under development for PM

2.5

and PM

10-2.5

that offer substantial advantages over manual methods for implementation in routine air monitoring. These advantages include reduced operational cost, greater practicality for daily operation, availability of short-term measurements such as one-hour averages, and the possibility for near real-time, telemetered measurement acquisition. Accordingly, EPA is very interested in encouraging the further development of these continuous-type methods by providing requirements for designating such methods as Class III equivalent methods, so that they can be used in monitoring networks. Because no such explicit requirements exist, EPA is today proposing new Class III designation requirements for both PM

2.5

and PM

10-2.5

Unfortunately, the continuous-type methods for PM

2.5

and PM

10-2.5

often tend to have performance characteristics somewhat different than those of the corresponding reference method. Consequently, adequate comparability to the corresponding reference method measurements may be technically difficult to achieve. Thus, the comparability testing requirements for Class III candidate methods must be sufficiently sophisticated to effectively differentiate between a method that shows adequate comparability and one that does not. At the same time, the designation qualification requirements must not be impractically extensive or burdensome, such that monitoring instrument manufacturers seeking designation for their analyzers cannot afford or economically justify the testing regimen.

We are proposing to narrow the definition of Class III equivalent methods to apply only to continuous or semi-continuous analyzer methods having one-hour (or less) measurement resolution, because such methods are of the most interest to the air quality monitoring community. While it would be possible to develop new, noncontinuous (or non-semicontinuous) PM

2.5

or PM

10-2.5

methods that would be categorized as Class III as currently defined, there is little, if any, technical need or economic incentive for instrument manufacturers to do so. Restricting the Class III definition to continuous analyzers, as proposed, would offer a substantial technical advantage by allowing the establishment of somewhat more tolerant limits of adequate comparability than would be necessary if non-continuous methods were included. This statistical advantage arises because the analyzers are operated continuously rather than on an intermittent, one-in-six day or one-in-three day schedule, which is typical of manually operated sampler methods.

Any of the currently existing or proposed requirements for designation of reference methods and Class I and Class II equivalent methods for PM

2.5

or PM

10-2.5

that would or should reasonably apply to a specific Class III candidate method would be required for the candidate Class III equivalent method, as well. But because of the wide variety of measurement techniques or technologies possible for a Class III candidate method, many of these existing requirements would not, or may not, apply. Therefore, the proposed requirements for PM

2.5

and PM

10-2.5

Class III candidate equivalent methods are based largely on demonstrating comparability between candidate method measurements and concurrent reference method measurements when both methods are collocated at several diverse monitoring and during different seasonal periods. These proposed requirements would be added to subpart C of 40 CFR part 53. Because we intend that most of the PM

10-2.5

monitors in the network use continuous or semi-continuous methods, the proposal of Class III approval requirements is particularly important for PM

10-2.5

Although candidate PM

2.5

and PM

10-2.5

Class III equivalent methods would have hourly measurement resolution, this capability would not be subject to comparability requirements because both PM

2.5

and PM

10-2.5

FRM have only 24-hour measurement capability.

In developing these proposed new requirements for PM

2.5

and PM

10-2.5

Class III candidate equivalent methods, EPA has attempted to provide requirements that effectively reject inadequately comparable methods while minimizing the testing burden to the extent possible. Because the performance characteristics of Class III methods are likely to vary at monitoring sites having differing climatic and aerosol conditions, comparison tests would be required at sites in three specified areas of the continental U.S. during winter and summer seasons (winter in only one of the areas). The EPA believes these requirements would provide the minimum of test venues necessary to represent an adequate degree of monitoring site diversity for designation of a candidate equivalent method. However, EPA specifically solicits comments on the adequacy of the proposed geographical test areas, the appropriateness of the proposed seasonal requirements, and whether an additional test site may be needed (including the nature of such an additional site).

4. Specific Requirements for Class III Equivalent Methods

The proposed amendments to 40 CFR part 53 would revise the requirements for comparison tests and the allowable quantitative deviation from reference method measurements that are based on statistical analyses. The EPA has previously used a documented procedure

and a special computer software aid

to establish data quality objectives (DQO) for PM

2.5

monitoring data so that such data can be used effectively in making decisions regarding attainment of the NAAQS for PM. Using these established DQO and the software, statistical analyses of both

actual and simulated PM

2.5

monitoring data

28 29

were carried out to confirm the suitability of the statistical parameters selected to describe a comparison relationship between the candidate and reference methods and to set appropriate and optimal limits for their values in the proposed Class III equivalent method tests. These quantitative requirements then define the minimum candidate method comparability performance that would be necessary to provide PM

2.5

monitoring data of sufficient quality to meet the established DQO.

The DQO for PM

10-2.5

monitoring data have recently been developed and are incorporated into 40 CFR part 58, appendix A. These DQO are similar to the DQO for PM

2.5

. Accordingly, the requirements proposed for PM

10-2.5

methods are similar to those proposed for PM

2.5

methods.

Furthermore, similar or parallel requirements are also proposed for Class II equivalent methods for PM

10-2.5

as well as for PM

2.5

. However, the proposed requirements for Class II equivalent methods for PM

10-2.5

are stricter with regard to additive bias (intercept) since this method would also support other monitoring objectives. These latter requirements proposed for PM

2.5

Class II methods would replace the existing test requirements with the more advanced, DQO-based requirements.

U.S. Environmental Protection Agency. Guidance for the Data Quality Objectives Process. EPA QA/G-4, EPA/600/R-96/055. August 2000.

U.S. Environmental Protection Agency (2004b) DQO Companion Tool, Version 2.0. 2004.

http://www.epa.gov/ttn/amtic/dqotool.html

Data Quality Objectives for PM Continuous Methods. Prepared for U.S. Environmental Protection Agency by ManTech Environmental Technology, Inc. EPA Contract 68-D-00-206, Report TR-4423-03-08, June 2003.

Data Quality Objectives for PM Continuous Methods II. Prepared for U.S. Environmental Protection Agency by ManTech Environmental Technology, Inc. EPA Contract 68-D-00-206. Report TR-CAN-04-02, June 2004.

Criteria for Designation of Equivalence Methods for Continuous Surveillance of PM

2.5

Ambient Air Quality. Prepared for U.S. Environmental Protection Agency by B. Coutant and J. Sanford, Battelle Columbus, EPA Contract 68-D-02-061, 2004.

Method Equivalency Development for PM

10-2.5

. Prepared for U.S. Environmental Protection Agency by B. Coutant, Battelle Columbus, 2005.

The parameters selected to estimate the performance of PM

2.5

and PM

10-2.5

Class II and Class III candidate method measurements relative to the performance of the reference method in the proposed field tests are precision, correlation, and the linear regression slope and intercept of a linear plot fitted to corresponding candidate and reference method mean measurement data pairs. Statistical analyses based on the DQO model show that the precision of a candidate method is not, statistically, very important to annual concentration averages used for NAAQS attainment decisions, but would be important for a daily standard. Precision is also consequential for other important aspects and applications of the PM

2.5

or PM

10-2.5

monitoring data. Accordingly, the proposed amendments would include a minimum requirement for an estimate of the candidate method precision for 24-hour measurements.

A minimum requirement for an estimate of reference method precision in the tests, as well as a test for possible anomalous reference method measurement values, also are proposed to ensure that the quality of the reference method measurements used for the test meets the expected reference method performance. The proposed numerical limits for the Class II and III precision test requirements for both the reference and candidate methods are somewhat larger than those currently prescribed for Class I PM

2.5

methods because the Class II and III precision would be calculated as the root mean square average, rather than the simple average, of the daily precision values determined from multiple samplers or instruments. This more statistically appropriate aggregation of precision is consistent with the way precision would be expressed under proposed revisions to the data quality assessment provisions in appendix A to 40 CFR part 58.

As noted above, the proposed revision to the definition for Class III equivalent methods would require such methods to provide one-hour (or less) concentration measurements, because such short-term measurements are useful for a variety of applications. The EPA proposes that hourly measurements from Class III comparability tests be recorded and submitted as part of the required test data. No requirement for the precision of these hourly measurements is included in the proposed amendments because no one-hour DQO have been established for either PM

2.5

or PM

10-2.5

measurements and neither of the PM

2.5

or PM

10-2.5

reference methods provide one-hour data or performance goals. Nevertheless, in view of the substantial potential utility of one-hour PM

2.5

and PM

10-2.5

measurements, EPA solicits comments on whether requirements for one-hour measurement precision should be included in the Class III equivalent method designation requirements. In particular, comments are requested on whether such requirements, if included, should provide merely an assessment of one-hour precision or a specified standard of performance, and if the latter, to what extent would it be appropriate to reject a candidate method that exhibited poor one-hour precision but adequate 24-hour precision.

The regression comparability parameters proposed for Class II and Class III candidate methods would be interpreted in ways somewhat different from those now used for determining candidate method comparability for other types of candidate equivalent methods for PM. The slope (multiplicative bias) and intercept (additive bias) are the performance parameters most critical in achieving the DQO for making correct attainment decisions. However, these parameters are interrelated, and statistical analyses of simulated PM

2.5

data

show that the allowable limits for the intercept can be somewhat less stringent if they are made to be variable and related to the value obtained for the slope. Accordingly, EPA is proposing variable, slope-dependant limits for the intercept.

Battelle Columbus (2004).

Further, because Class III PM

2.5

and PM

10-2.5

equivalent methods would be redefined as continuous or semi-continuous methods, such methods would normally be operated continuously, just as continuous gaseous pollutant analyzers are, rather than on a one-day-in-six sampling schedule typically used for PM

2.5

reference method sampling. Again, statistical analyses

show that this more frequent (daily) sampling allows the intercept limits to be set even wider than would be needed for one-in-six day sampling and still meet the established DQO. The actual intercept limits for PM

10-2.5

methods proposed today are somewhat more restrictive than the analyses would indicate to provide a factor of safety to account for inherent differences between the way candidate methods would be operated in the proposed equivalent method tests and the way they would be operated routinely in State monitoring networks.

ManTech Environmental Technology, Inc. (June 2003); ManTech Environmental Technology, Inc. (June 2004); Battelle Columbus (2004); Battelle Columbus (2005).

Another difference in the way the conventional comparison parameters would be interpreted relates to the proposed lower limit requirement for the comparison correlation. The correlation test is instrumental in detecting longer-term method variability, such as seasonal bias. By its nature, the correlation value calculated for the comparison is quite dependent on the range of concentrations measured in the tests. The comparison tests are subject to the actual PM

2.5

or PM

10-2.5

concentrations available at the test site, which are generally related to variable atmospheric conditions during the test period and consequently may

sometimes occur in a rather narrow range. Therefore, the minimum value proposed for this statistic is not a fixed value but rather a variable that is related to the concentration coefficient of variation (CCV), which is a measure of the range of the concentrations measured in the test. This variable limit for correlation would provide a more effective test without unnecessarily failing test data representative of an unfortunately limited range of test concentrations.

One minor difference from the reference method would be necessitated by the proposed Class III comparison tests. The proposed reference methods for PM

2.5

and PM

10-2.5

specify a sampling period tolerance of 23 to 25 hours. Experience has shown that in multiple-sampler candidate method tests, which may be frequently combined with tests of additional instruments to reduce overall testing costs, the time required to properly change sample filters and service the samplers and other instruments between sample periods often requires more than one hour. Accordingly, the proposed test protocol would allow a 22-hour minimum sample period for the reference method to allow complete sample set acquisition within a 24-hour period. This proposed revision in the reference method protocol should have very little, if any, adverse impact on the results of the comparability tests.

The proposed requirements for PM

10-2.5

and PM

2.5

Class II and Class III equivalent methods are the least stringent requirements that would provide reasonable assurance that candidate methods meeting these requirements will produce monitoring data of quality commensurate with the quality of reference method data and that the data will meet the DQO established for PM

2.5

and the proposed DQO for PM

10-2.5

. While recent field studies suggest some potential PM

10-2.5

continuous methods look promising,

it is not certain at this time whether any current commercial continuous or nearly continuous methods can yet meet the proposed requirements for Class III methods. However, EPA believes that the establishment of these requirements would provide a definitive goal which instrument manufacturers could achieve.

U.S. Environmental Protection Agency. Multi-Site Evaluations of Candidate Methodlogies for Determining Coarse Particulate Matter (PM

10-2.5

) Concentrations: August 2005 Updated Report Regarding Second-generation and New PM

10-2.5

Samplers.

5. Proposed Changes to Requirements for PM

and PM

2.5

Class I and Class II Equivalent Methods

The proposed amendments would revise the existing provisions for PM

and PM

2.5

Class I and II candidate equivalent methods. These changes would clarify or simplify current provisions or implement minor improvements to test protocols suggested by experience and information acquired in processing equivalent method applications for these methods. The proposed changes would have very little, if any, impact on the nature, efficacy, or extent of any of the test requirements.

In the tests for PM

and PM

2.5

Class I and II candidate equivalent methods, the minimum separation distance between sampler or analyzer inlets is proposed to be reduced from 2 meters to 1 meter for instruments having flow rates less than 200 liters per minute. One meter separation has been found to be entirely adequate for such low-flow-rate instruments, and the change is consistent with a similar minimum separation allowance for audit samplers used in assessing the precision of network PM

2.5

samplers.

An identical change is also proposed for appendix A to 40 CFR part 58.

Quality Assurance Guidance Document: Field Standard Operating Procedures for the PM

2.5

Performance Evaluation Program. U.S. Environmental Protection Agency. Office of Air Quality Planning and Standards, November 1998, Section 4, page 8.

Another proposed change would replace existing requirements for Class II PM

2.5

equivalent methods with similar but new DQO-based requirements. These proposed requirements are similar to the Class III requirements and would be based on daily sampling. Therefore, PM

10-2.5

and PM

2.5

Class II equivalent methods used for determining compliance with the PM NAAQS would generally be restricted to daily operation. However, as discussed previously, filter-based integrated methods (such as Class II equivalent methods) are not likely to be widely used for compliance monitoring. These methods would be used more for chemical analysis of samples to characterize the species of PM in a monitoring area, which would not require daily operation of the samplers. For Class II methods (for either PM

2.5

and PM

10-2.5

methods), the test sites would be similar in character to those for Class III methods, but only two test sites (one eastern and one western) rather than three, and tests in only one season at any time of year rather than two seasons, would be required. These requirements would allow tests for PM

2.5

and PM

10-2.5

methods (or for Class II and Class III method) to be tested simultaneously, to reduced testing costs. Flow rates in the existing PM

2.5

FRM and proposed PM

10-2.5

FRM would be operated under conditions of actual ambient temperature and barometric pressure, ensuring compatibility of the measured sample flows. The EPA solicits comments on the adequacy and appropriateness of these tests requirements for Class II methods.

In addition, the proposed amendments would lower many of the minimum concentration limit specifications for various existing test requirements for PM

and PM

2.5

Class I and Class II candidate equivalent methods. These minimum limits were established either to avoid possible difficulties with interpretation of test results due to increased measurement variability that often occurs at very low concentrations or to require a wide range of concentration measurements for the test. However, experience has shown that these lower limits are unnecessarily conservative and can be decreased considerably without encountering undue variability in the measurements or an insufficient range of concentrations. Further, applicants often have difficulty obtaining a sufficient number of measurement sets that meet some of these minimum limits. The proposed decreases in these minimum limits would reduce the number of test measurement sets that are rejected as unacceptable due to test concentration levels failing to meet the test requirements without compromising the efficacy of the tests. These changes would reduce the costs to applicants of conducting the tests.

6. Other Proposed Changes

The proposed amendments would make subpart C of 40 CFR part 53 easier to understand by consolidating the provisions for the various types of candidate equivalent methods. This reorganization results in numerous minor editorial and section number changes of no technical impact. The entire text of 40 CFR part 53, subpart C is reprinted in the proposed amendments.

We are proposing numerous minor changes which are needed to incorporate new provisions for PM

10-2.5

methods into subparts A, C, E, and F of 40 CFR part 53, as well as a few minor changes that would apply to methods for PM

2.5

or other pollutants. As noted above, the definition of a “Class III equivalent method” in 40 CFR 53.1 would be modified to include only methods that provide automated

continuous or semi-continuous measurements of PM

2.5

and PM

10-2.5

with one-hour or less resolution. We are also proposing definitions for the terms, “PM”, “PM

10-2.5

sampler”, and “PM

10C

sampler”. Another proposed change, to paragraph (4) of 40 CFR 53.3 (General requirements for an equivalent method), would clarify that Class III PM

10-2.5

and PM

2.5

candidate equivalent methods would be subject to applicable requirements for PM

10-2.5

or PM

2.5

reference methods contained in those reference methods (40 CFR part 50, appendixes L and O) and applicable requirements for Class I and Class II equivalent methods contained in subparts E and F of 40 CFR part 53, in addition to the proposed amendments to subpart C. The requirement in 40 CFR 53.5 (Processing of applications) to publish a notice in the

Federal Register

upon receipt of an application would be deleted, as would the requirements in 40 CFR 53.51(f)(2) and 53.2(a) for manufacturers of PM

2.5

designated method samplers to submit an annual Product Manufacturing Checklist. These requirements have proved to be of little value, and the significant cost burden to the Government and to applicants for these activities can therefore be eliminated. The proposed amendments would also delete the requirement in 40 CFR 53.8 (Designation of reference and equivalent methods) for publishing a notice of designation in the

Federal Register

no later than 15 days after the date of the determination. We are proposing to delete the 15-day requirement because it is not achievable within the confines of EPA's internal review process.

C. What Are the Proposed Requirements for Quality Assurance Programs of the National Ambient Air Monitoring System?

A quality system provides a framework for planning, implementing and assessing work performed by an organization and for carrying out required quality assurance (QA) and quality control (QC) activities. The proposed amendments to 40 CFR part 58, appendix A would provide the requirements necessary to develop quality systems for the NCore, State and Local Air Monitoring Stations (SLAMS), and Prevention of Significant Deterioration (PSD) networks. The proposed revisions address responsibilities for implementing the quality system for both EPA and monitoring organizations, as well as adherence to the Agency's QA policy, data quality objectives (DQO), and the minimum QC requirements and performance evaluations needed to assess the data quality indicators of precision, bias, detectability, and completeness. In addition, the proposed amendments would describe the required frequency of the QC requirements and performance evaluations, the data to be collected, and the statistical calculations for estimates of the data quality indicators at various levels of aggregation. The revised statistical calculations would be used to determine attainment of the DQO. The proposed amendments would also identify national programs that help determine data quality comparability across individual monitoring programs.

The EPA has not conducted a thorough review of the quality system for many years. Based on our review of the existing QA program in 40 CFR part 58, appendices A and B, we are proposing changes to make the requirements consistent with our current QA policy, meet the objectives of the NCore, SLAMS, and PSD monitoring networks, and make the requirements more user-friendly. These proposed changes would produce a more consistent QA program across pollutant categories that fosters use of new technologies by more directly linking instrument performance with programmatic objectives. The proposed revisions were developed with the assistance of a stakeholder group (QA Strategy Workgroup) composed of QA representatives from EPA, State, local, and tribal monitoring organizations. Recommendations from the workgroup are provided in one of the draft versions of the National Ambient Air Quality Strategy document.

We solicit comments on all of the following proposed amendments to 40 CFR part 58, appendix A.

The National Ambient Air Monitoring Strategy (Final Draft). U.S. Environmental Protection Agency. Office of Air Quality Planning and Standards, APril 2004. Some of the detailed content of the April 2004 draft, including some of the workgroup recommendations are not included in the subsequent December 2005 version.

1. Consolidation of Quality Assurance Requirements

The requirements for State and local air monitoring stations (SLAMS) and prevention of significant deterioration (PSD) monitoring stations have been combined from two separate appendices, 40 CFR part 58, appendices A and B, into one single appendix A because both programs have similar QA requirements.

2. Realignment to Current EPA Quality Assurance Policies

EPA Order 5360.1 A2 requires agencies that accept Federal grant funding for their air monitoring programs to have a QA program with certain elements including quality management plans (QMP), quality assurance project plans (QAPP), and a person designated as the quality assurance manager. Many of these elements are not in the existing regulations, which predate EPA Order 5360.1 A2 (revised in 2000), but would now be added under today's proposal. Grantee agencies have been following the requirements of EPA Order 5360.1 A2 for several years, and as a result, we do not expect these proposed revisions would have a significant impact on resources beyond the existing program. Copies of EPA Order 5360.1 A2 are available in the docket for this proposal as well as on EPA's Internet site

http://www.epa.gov/quality1.

A QMP is a document that describes an organization's quality system including its policy and procedures, functional responsibilities of management and staff, and other general practices of its data collection program. Project-specific details are documented in a QAPP. A QAPP would document, for example, how the PM

2.5

air monitoring network will be operated and how sampler performance will be controlled and data quality evaluated.

EPA Order 5360.1 A2 requires grantee agencies involved with data collection activities to identify a quality assurance manager. The proposed amendments to 40 CFR part 58, appendix A would require each State (or delegated monitoring agency) to identify and maintain a “QA management function”. This proposed language captures the essence of the requirements in EPA Order 5360.1A2, while befitting the nature of the ambient air monitoring community which is made up of large and small (local and tribal) organizations.

The EPA also proposes to revise the QA program by emphasizing the DQO process. A DQO is a qualitative and quantitative statement that defines the appropriate quality of data needed for a particular decision—for example, the data quality necessary for EPA or a monitoring organization to make data comparisons against the National Ambient Air Quality Standards (NAAQS). The DQO help to establish the requirements for precision, bias, completeness, and detectability and the rationale for their acceptance criteria.

The proposed amendments would require monitoring organizations to

evaluate PM

10-2.5

and ozone monitoring system performance through the DQO process. This is consistent with the existing requirement for organizations to evaluate their PM

2.5

monitoring system performance using the DQO process. Priority for these evaluations is placed on PM

2.5

, PM

10-2.5

, and ozone as these are the pollutants of most concern across the country. Quality assurance procedures such as determining precision through collocated sampling and determining bias through an independent performance evaluation program for PM

10-2.5

are proposed to follow the same basic approach as the PM

2.5

monitoring network. The proposed precision and bias measurement uncertainty goals are identified in 40 CFR part 58, appendix A. The proposed amendments to appendix A would also specify that EPA is responsible for the development of the DQO for NCore multi-pollutant stations and State and local air monitoring stations (SLAMS).

3. Quality Assurance Requirements for PM

, PM

10-2.5

and PM

2.5

The proposed QA requirements for PM

10-2.5

would follow the same approach as the requirements that currently apply to both automated and manual PM

and PM

2.5

monitors. These requirements would include the implementation of flow rates audits conducted by the monitoring organization, collocated monitoring, and performance evaluations. Statistical evaluations have allowed us to reduce collocation and performance evaluation sampling frequencies without significant affects to data quality assessments.

We are proposing to amend the PM

2.5

and PM

collocation sampling frequency requirement. Statistical assessments of the collocated PM

2.5

and PM

data reveal that adequate estimates of precision at the primary quality assurance organization could be made at a reduced sampling frequency. Consequently, we are proposing to reduce the frequency from every 6 days to every 12 days. This change would reduce the burden on the monitoring organization without a significant effect on precision estimates. This proposal does not include a reduction in the collocation requirements for total suspended particulate (TSP) or PSD monitors. In addition, we are proposing to revise the concentration limits applicable to collocated pairs of monitors that are used to provide precision estimates. The concentration limits would be reduced from 6 micrograms per cubic meter (μg/m

) to 3 μg/m

for PM

2.5

and from 20 μg/m

to 15 μg/m

for PM

(high-volume samplers). Statistical evaluation of three years of PM

2.5

and PM

data revealed comparable estimates of precision using data from both of these reduced concentration ranges, and that the addition of the data at these lower ranges will increase the level of confidence in the precision estimates. This proposed change would make the collocation sampling frequency requirement consistent for PM

2.5

and PM

10-2.5

. A document describing the possible new approach is available in the docket.

Proposal to Change the PM

2.5

and PM

Collocation Sampling Frequency Requirement,

http://www.epa.gov/ttn/amtic/pmqainf.html

We are proposing to revise the sampling frequency for the implementation of the PM Performance Evaluation Program (PEP). This proposed approach used historical PM

2.5

precision and bias data to identify the minimum number of performance evaluations required for all primary quality assurance organizations to provide an adequate assessment of bias, rather than the current requirement that a uniform 25 percent of monitors in a primary quality assurance organization be evaluated each year. The revision would establish an equitable sampling frequency of five valid audits a year for organizations with less than or equal to five monitoring sites and eight valid audits a year for those organizations with greater than five monitoring sites. A valid performance evaluation audit means that both the primary monitor and PEP audit concentrations are valid and above 3 μg/m

. As an example, if a primary quality assurance organization had 20 monitoring sites, the current requirement would require five sites (25 percent of network) to be audited four times each year (one each quarter) for a total of 20 audits. The new proposal would simply require eight audits be provided (distributed across each quarter) and that all monitoring sites be audited within a six year period in order to provide a representative estimate of bias for the monitoring network. This would equate to distributing eight audits (or five for networks less than or equal to 5) at 15 percent of the monitoring network sites. In addition, each method designation must be audited. Therefore, if a primary quality assurance organization had two different monitoring instruments in their network, both would need PEP audits each year. Since bias data quality objectives are evaluated on 3 years of PEP audits, both sampling frequencies should provide us with reasonable assessments of bias. Preliminary assessments of the impact of the possible new method show that organizations with smaller networks would need more audits but fewer audits would be needed at organizations with larger networks. The net result across all primary quality assurance organizations would be fewer audits, comparable bias results, and reduced resource burden. A document describing this possible approach is available in the docket.

Review of the Potential to Reduce or Provide a More Cost Efficient Means to Implement the PM

2.5

Performance Evaluation Program,

http://www.epa.gov/ttn/amtic/pmpep.html.

4. Requirements to Ensure Adequate Independent Quality Assurance for All Pollutants Subject to National Ambient Air Quality Standards

We are proposing to revise the current regulatory requirements dealing with responsibilities for independent assessments of monitoring system performance. These evaluations are the subject of sections 2.4 and 3.5.3.1 of the current appendix A to 40 CFR part 58. Section 2.4 of appendix A to 40 CFR part 58 applies to all National Ambient Air Quality Standards (NAAQS) pollutants and section 3.5.3.1 is applicable only to PM

2.5

. Currently, section 2.4 of appendix A requires the monitoring organization to “participate” in EPA's National Performance Audit Program (NPAP). For the last few years, EPA has considered that monitoring organizations are in compliance with the requirements of section 2.4 if, at a minimum, the organizations made their monitoring sites and equipment accessible to EPA or contractors for conducting the performance evaluations. For continuous gas instruments, a performance evaluation involves the introduction of a gas or gases of independently known concentration to determine the bias of the local monitor.

Section 3.5.3.1 of appendix A to 40 CFR part 58 describes the Performance Evaluation Program (PEP) for PM

2.5

. The PEP requirements are functionally similar to the NPAP requirements but differ in its specifics because of the nature of particulate matter sampling (i.e., it is not possible to introduce air with a known concentration of PM

2.5

into a monitor). Under the PEP for PM

2.5

, a local monitor is evaluated by placing a second, independently-maintained Federal reference method (FRM) monitor next to the local monitor and allowing both monitors to sample for 24 hours. The filter from the independent FRM monitor is then shipped to an independent laboratory

where it is weighed and the resulting independently calculated concentration is compared to the concentration from the local monitor. The resulting difference in concentrations between the independent FRM monitor and local monitor is used to calculate the bias between the sampler results.

The monitoring organization is responsible for having these PM

2.5

performance evaluations take place, or only for giving access to its sites for EPA staff or contractors to perform them. In practice, most monitoring organizations comply with the requirements in section 3.5.3.1 by giving access to EPA staff or contractors and by accepting that EPA funds this activity by holding back part of the grant funding that might otherwise go directly to the monitoring organization. One State complies with requirements in section 3.5.3.1 by having independent audits in one part of the State performed by personnel and laboratories from the monitoring organization that is responsible for daily operations in another part of the State.

The EPA proposes to revise the text of 40 CFR part 58, appendix A to clearly provide that it is the responsibility of each monitoring organization to make arrangements for, and to provide any necessary funding for, the conduct of adequate independent performance evaluations of all its FRM or Federal equivalent method (FEM) criteria pollutant monitors. The proposed language would also clearly indicate that it is the monitoring organization's choice whether to obtain its independent performance evaluations through EPA's NPAP and PM

2.5

PEP programs, or from some other independent organization. An independent organization could be another unit of the same agency that is sufficiently separated in terms of organizational reporting and which can provide for independent filter weighing and audit gas naming. This proposed approach would ensure that adequate and independent audits will be performed but would provide flexibility in the implementation approach.

Monitoring organizations that choose to comply with the revised provisions of appendix A to 40 CFR part 58 regarding performance evaluations by relying on EPA audits, for PM

2.5

, PM

10-2.5

, and/or other NAAQS pollutants, would be required to agree that EPA hold back part of the grant funds they would otherwise receive directly. The EPA intends to develop guidance for monitoring organizations that choose to comply by obtaining audit services from elsewhere. To ensure national consistency and effective audits, this guidance will include provisions for EPA certification of data comparability for audit services not provided by EPA and for traceability of gases and other audit standards to national standards maintained by the National Institute for Standards and Technology.

5. Revisions to Precision and Bias Statistics

We are also proposing to change the statistics for assessment of precision and bias for criteria pollutants. Two important data quality indicators that are needed to assess the achievement of DQO are bias and precision. Statistics in the current requirements of 40 CFR part 58, appendix A (with the exception of PM

2.5

) combine precision and bias together into a probability limit at the primary quality assurance organization level of aggregation. In addition, the statistical calculations of precision and bias vary among criteria pollutants and between manual and automated methods within the same pollutant. Since the DQO process uses separate estimates of precision and bias, we examined assessment methods that were statistically reasonable and simple. The proposed assessment methods are based on the QA measurements that are currently required in 40 CFR part 58, appendix A.

For sulfur dioxide (SO

), nitrogen dioxide (NO

), carbon monoxide (CO), and ozone (O

), we are proposing to estimate precision and bias on confidence intervals at the site level of data aggregation rather than the primary quality assurance organization. Estimates at the site level can be accomplished with the automated methods for SO

, NO

, CO and O

because there is sufficient QC information collected at the site level to perform adequate assessments. Since the criteria pollutant data are used for very important decisions (comparison to the NAAQS), providing precision and bias estimates at upper confidence limits would provide a higher probability of making appropriate decisions. The intent of this proposed change is to move organizations to a “performance-based” quality system. Organizations that demonstrate acceptable performance would be allowed the flexibility to reduce the frequency of certain QC checks. These agencies are expected to shift resources used for these QC checks into higher priority QA work. A document describing this possible new approach is available in the docket.

Proposal: New Method for Estimating Precision and Bais for Gaseous Automated Methods for Ambient Air Monitoring Program,

http://www.epa.gov/ttn/amtic/files/ambient/gagc/proprecision.pdf.

The precision and bias statistics for PM measurements (PM

, PM

10-2.5

and PM

2.5

) would be generated at a primary quality assurance organization level because, unlike the gaseous pollutants, only a percentage of the sites have precision and bias checks performed in any year. As with the gaseous pollutants, the statistics would use the confidence limit approach. Using a consistent set of statistics would simplify procedures by removing a significant number of equations and confusing language in the appendix.

We are also proposing to change the precision and bias statistics for lead (Pb) to provide a framework for developing and assessing DQO. The QC checks for Pb come in three forms: flow rate audits, Pb audit strips, and collocation. The EPA proposes to combine information from the flow rate audits and the Pb audit strips to provide an estimate of bias. Precision estimates would still be made using collocated sampling but the estimates would be based on the upper 95 percent confidence limit of the coefficient of variation, similar to the method described for the automated instruments.

6. Program Updates

We are also proposing several QA program changes to update the existing requirements in 40 CFR part 58 to reflect current program needs and terminology:

• We are proposing to remove SO

and NO

manual audit checks. A review of all SLAMS/NAMS/PAMS sites by monitor type revealed that no monitoring organizations are using manual SO

or NO

methods, nor are any monitoring organizations expected to use these older technologies. Instead of the old manual methods, monitoring sites are using continuous methods to perform these audit checks. We are proposing to remove the manual method QC checks because the continuous check methods are covered by the current QA procedures.

• We are proposing to change the concentration ranges for QC checks and annual audit concentrations. The one-point QC check concentrations for the gaseous pollutants SO

, NO

, O

and CO would be expanded to include lower concentrations. Lower audit ranges would also be added to concentration ranges in the annual audit concentrations. Adding or expanding the required range to lower concentration ranges is appropriate due to the lower measured concentrations at many monitoring sites as well as the potential for NCore stations to monitor areas where concentrations are at trace ranges. In addition, EPA proposes that

the selection of QC check gas concentration must reflect the routine concentrations normally measured at sites within the monitoring network in order to appropriately estimate the precision and bias at these routine concentration ranges.

• We are proposing to revise the PM

collocation requirement. Currently, 15 percent of all PM

2.5

sites are required to maintain collocated samplers. For consistency, the proposed amendments would change the PM

collocation requirement to match the PM

2.5

requirement. This proposed change would make the collocation requirement consistent for PM

2.5

and PM

10-2.5

• We are proposing to amend the PM

2.5

and PM

collocation sampling frequency requirement. Statistical assessments of the collocated PM

2.5

and PM

) to 3 μg/m

for PM

2.5

and from 20 μg/m

to 15 μg/m

for PM

(high-volume samplers). Statistical evaluation of 3 years of PM

2.5

and PM

2.5

and PM

10-2.5

• We are proposing to revise the requirements for PM

2.5

flow rate audits. Based on an evaluation of flow rate data and discussions within the QA Strategy Workgroup, we are proposing to reduce the frequency of flow rate audits from quarterly to semiannually and remove the alternative method which allows for obtaining the precision check from the analyzers internal flow meter without the use of an external flow rate transfer standard. Most monitoring organizations participating in the QA Strategy Workgroup considered auditing with a external transfer standard to be the preferred method and believed that the quarterly audit data demonstrates the instruments are sufficiently stable to reduce the audit frequency. The proposed amendments would provide an efficient and effective approach by reducing audit frequency to an adequate level while ensuring the use of a preferred approach.

D. What Are the Proposed Monitoring Methods for the National Ambient Air Monitoring System?

1. Federal Reference Methods and Federal Equivalent Methods

Monitoring methods used in the multi-pollutant NCore and SLAMS networks would include Federal reference methods (FRM), Federal equivalent methods (FEM), and other methods designed to meet the data quality objectives of the network being deployed. When appropriate, the proposed amendments place emphasis on continuous methods over filter-based methods to provide for highly time-resolved data for better characterization of diurnal patterns of air pollution and for timely public availability of data. While more emphasis is placed on continuous methods, a limited number of filter-based methods would still be retained in most networks to tie together historical data sets with new monitoring data. EPA's strategy for selecting the proposed monitoring methods for the National ambient air monitoring system was to select methods that meet data quality objectives for each pollutant and that have the most utility to support multiple monitoring objectives. Specifics on the monitoring methods proposed for use at each type of site are described below.

• A wide variety of research, FRM/FEM or other routine methods could be used at NCore research-grade stations. Maximum flexibility is provided in the proposed amendments for these sites because they would be used to investigate the atmospheric processes and air chemistry that go beyond the capabilities of characterizing the air with routine monitoring methods.

• NCore multi-pollutant stations would use FRM or FEM for criteria pollutants when the expected concentration of the pollutants are at or near the level of the National Ambient Air Quality Standards (NAAQS). For criteria pollutant measurements of carbon monoxide (CO) and sulfur dioxide (SO

), where the level of the pollutant is well below the NAAQS, it may be more appropriate to operate higher sensitivity monitors than FRM or FEM. In these cases, the higher sensitivity methods are expected to support different monitoring objectives than the FRM or FEM. In some limited cases, higher-sensitivity gas monitors have also been approved as FEM and can serve both NAAQS and other monitoring objectives. Options for high-sensitivity measurements of CO, SO

, and total reactive nitrogen (NO) are described in the report, “Technical Assistance Document for Precursor Gas Measurements in the NCore Multipollutant Monitoring Network.”

• State and local air monitoring stations would use FRM or FEM for criteria pollutants. For PM

2.5

, these sites could also use approved regional methods (ARM), which are described in section IV.D.2 of this preamble.

• Photochemical assessment monitoring stations (PAMS) would use the ozone (O

) ultraviolet photometry FEM and the nitric oxide (NO) and nitrogen dioxide (NO

) chemiluminescence FRM for criteria pollutant measurements. Methods for volatile organic compounds (VOC) including carbonyls, additional measurements of gaseous nitrogen, such as NO

, and meteorological measurements are routinely operated at PAMS. Because these measurements are not of criteria pollutants, the methods are not subject to the requirements for reference or equivalent methods. However, these methods are described in detail in the report, “Technical Assistance Document (TAD) for Sampling and Analysis of Ozone Precursors.”

Technical Assistance Document (TAD) for Sampling and Analysis of Ozone Precursors. U.S. Environmental Protection Agency. HUman Exposure and Atmospheric Sciences Division. EPA/600-R-98/161. September 1998. Available at:

http://www.epa.gov/ttn/amtic/pams.html.

• Special purpose monitoring (SPM) sites have no restrictions on the type of method to be utilized. While FRM and FEM can be employed at SPM sites, other methods, not limited to continuous, high-sensitivity, and passive methods, may also be utilized. Because SPM sites are designed to encourage monitoring, agencies are expected to design SPM sites with methods to meet specific monitoring objectives that may not be achievable with FRM or FEM. For instance, a community may be concerned with a source impacting their neighborhood. Because many PM FRMs are filter-based manual methods, having a 24-hour sample may not indicate if the source impacted the neighborhood because of the meteorological variability during the sample collection period. However, a continuous method may be able to provide the high-time resolution

necessary to detect the short-term impacts of a plume on a neighborhood. Another example could be the utilization of passive monitors deployed at many locations to determine the location of maximum concentrations within a neighborhood. Additional information on SPM is included in section IV.E.9 of this preamble.

2. Approved Regional Methods for PM

2.5

The proposed amendments also expand the use of alternative PM

2.5

measurement methods through approved regional methods (ARM). The proposed amendments to 40 CFR part 58, appendix C extend the existing provisions for EPA approval of a nondesignated PM

2.5

method as a substitute for a FRM or FEM at a specific individual site to a network of sites. This approval would be extended on a network basis to allow for flexibility in operating a hybrid network of PM

2.5

FRM and continuous monitors. The size of the network, in which the ARM could be approved, would be based on the location of test sites operated during the testing of the candidate ARM. The proposed amendments require that test sites be located in urban and rural locations that characterize a wide range of aerosols expected across the network. A hybrid network of monitors would be operated to address monitoring objectives beyond just determining compliance with NAAQS. The hybrid network would lead to a reduced number of existing FRM samplers for direct comparison to NAAQS and an increase in continuous samplers that meet specified performance criteria related to their ability to produce sound comparisons to FRM data. Those ARM that meet the specified performance criteria would be approved for direct comparison to PM

2.5

NAAQS.

Performance criteria for approval of ARM would be used to determine whether the continuous measurements are sufficiently comparable for integration into the PM

2.5

network used in NAAQS decisions. These criteria are the same criteria for precision, correlation, and additive and multiplicative bias that are proposed for approval of continuous PM

2.5

Class III equivalent methods, described in section IV.B.3 of this preamble. These performance criteria would be demonstrated by monitoring agencies independently or in cooperation with instrument manufacturers under actual operational conditions using one to two FRM and one to two candidate monitors each. This would be a departure from the very tightly-controlled approach used for national equivalency demonstration in which three FRM and three candidate monitors are operated. The ARM would be validated periodically in recognition of changing aerosol composition and instrument performance. These validations would be performed on at least two levels: (1) Through yearly assessments of data quality provided for as part of the on-going quality assurance (QA) requirements in 40 CFR part 58, appendix A, and (2) through network assessments conducted at least every 5 years as described in section IV.E.11 of this preamble.

The testing criteria EPA is proposing for approval of PM

2.5

continuous methods as ARM are intended to be robust but not overly burdensome. The two main facets of testing are the duration and location(s) of testing. The duration is expected to be one year to provide understanding of the quality of the data on a seasonal basis. The locations for testing are expected to be a subset of sites in a network where the State desires the PM

2.5

continuous monitor to be approved as an ARM. Testing would be carried out in multiple locations to include up to two Core-based Statistical Area/Combined Statistical Areas (CBSA/CSA) and one rural area or small city for a new method. For methods that have already been approved by EPA in other networks, one CBSA/CSA and one rural area or small city would be required.

To ensure that approvals of new methods are made consistently on a national basis, the procedures for approval of methods would be similar to the requirements specified in 40 CFR part 53, i.e., the EPA Administrator (or delegated office) would approve the application. However, to optimize flexibility in the approval process, all other monitoring agencies seeking approval of a method that is already approved in another agency's monitoring network may seek approval through their own EPA Regional Administrator. This approach should provide a streamlined approval process, as well as an incentive for consistency in selection and operation of PM

2.5

continuous monitors across various monitoring agency networks.

The proposed QA requirements for approval of continuous PM

2.5

ARM at a network of sites would be the same as for FEM in 40 CFR part 58, appendix A, except that 30 percent of the required sites that utilize a PM

2.5

ARM would be collocated with an FRM and required to operate at a sample frequency of at least a one-in-six day schedule. The higher collocation requirement would support the main goal of the particulate matter continuous monitoring implementation plan, which is to have an optimized FRM and PM

2.5

continuous monitoring network that can serve several monitoring objectives. The current 15 percent collocation requirement in 40 CFR part 58, appendix A is adequate to provide an estimate of site and network precision; however, a higher amount of collocation is necessary to retain a minimum number of FRM for continued validation of the ARM, direct comparison to NAAQS, and for long-term trends that are consistent with the historical data set archived in the Air Quality System. The collocated sites are to be located at the highest concentration sites, starting with one site in each of the largest population CBSA or CSA in the network and working to the next highest-population CBSA or CSA with the second site and so forth.

E. What are the Proposed Requirements for the Number and Locations of Monitors To Be Operated by State and Local Agencies?

The proposed amendments modify the requirements in appendix D to 40 CFR part 58 for the number and locations of monitors necessary to support ambient air data objectives. This proposal requires States to deploy a new network of multipollutant monitoring stations called the National Core (NCore) network; requires States to maintain robust networks for PM

2.5

and ozone (O

) and to establish a robust monitoring network for PM

10-2.5

; allows States to make major reductions in monitoring for other criteria pollutants, where concentration data are well below the applicable National Ambient Air Quality Standards (NAAQS) and are not expected to pose future air quality problems; and allows States to reduce the number of stations required for the NCore photochemical assessment monitoring stations (PAMS) network. We also propose to establish or modify certain monitoring frequency requirements.

This proposal allows for reductions in air pollution monitoring for select pollutants in geographic areas that do not have or are not expected to have related air quality problems, while increasing or maintaining monitoring sites in areas with continuing or new air quality problems. The proposal allows for reductions in the carbon monoxide (CO), sulfur dioxide (SO

), nitrogen dioxide (NO

), PM

, and lead (Pb) air monitoring networks in geographic areas with historically low concentrations of these specific pollutants, except cases in which the State implementation plan (SIP) or source permits specifically require

certain monitoring. However, monitoring requirements that are part of a SIP or permit should be revisited as part of the network assessments described in section IV.E.11 of this preamble. Overall, a limited number of these monitors are still expected, but not required, to be operated to support studies of air quality trends, to allow accountability for emissions control programs, and for health effects studies.

This proposal also requires States to increase or maintain monitoring sites in most areas with continuing or new air quality problems for O

and PM

2.5

. However, with EPA agreement, States would be allowed to move some monitors to better characterize the spatial variability of these pollutants.

As discussed in section IV.E.2 of this preamble, we also are proposing requirements for the minimum monitoring network for the proposed PM

10-2.5

NAAQS published elsewhere in this

Federal Register

Continuous PM

2.5

and PM

10-2.5

methods that can meet multiple monitoring objectives are being promoted by proposing new performance-based criteria for approval of these methods. See section IV.B of this preamble.

Under the proposed monitoring amendments, the PAMS network would remain a requirement for serious, severe, and extreme ozone nonattainment areas. However, EPA is promoting the development of more individualized PAMS networks to suit the specific data needs for a PAMS area. We propose to make the PAMS requirements more flexible to allow for this redesign.

Minimum criteria pollutant monitoring requirements, where proposed for retention or addition, would be based in part on population statistics. The Office of Management and Budget (OMB) has established standards for defining metropolitan and micropolitan statistical areas that replace metropolitan statistical areas defined in the 1990 standards (65 FR 82227, December 27, 2000). The EPA has traditionally used the 1990 metropolitan statistical area definitions within many of the air monitoring requirements including the numbers of monitoring sites within a network and the Air Quality Index (AQI) reporting requirements. The proposed amendments use the new OMB standards for defining metropolitan and micropolitan areas, as well as the new standards for Core-based Statistical Areas (CBSA) and Combined Statistical Areas (CSA).

1. Proposed Requirements for Operation of Multipollutant Monitoring Stations Identified as the National Core Network (NCore).

The EPA is proposing requirements applicable to States individually that may, in the aggregate, cause the deployment of a new network of monitors in approximately 60 mostly urban multipollutant stations. Most States would be required to operate at least one urban station; however, rural stations could be substituted in States that have limited dense urban exposures. States with Core-Based Statistical Areas (CBSA) often also have multiple air sheds with unique characteristics and, often, elevated air pollution. These States include, at a minimum, California, Florida, Illinois, Michigan, New York, North Carolina, Ohio, Pennsylvania, and Texas. These States would be required to identify one to two additional NCore stations in order to account for their unique situations. These stations, combined with about 20 multipollutant rural stations, which are not specifically being required of the States, would form the new multipollutant NCore network. The rural NCore stations will be negotiated using grant authority as part of an overall design of the network that is expected to leverage existing rural networks such as IMPROVE, CASTNET and, in some cases, State-operated rural sites.

These multipollutant NCore stations are intended to track long-term trends for accountability of emissions control programs and health assessments that contribute to ongoing reviews of the NAAQS; support development of emissions control strategies through air quality model evaluation and other observational methods; support scientific studies ranging across technological, health, and atmospheric process disciplines; and support ecosystem assessments. Of course, these stations together with the more numerous PM

2.5

and O

sites would also provide data for use in the NAAQS decision making process and for public reporting and forecasting of the AQI.

The EPA proposes that these multipollutant NCore stations be required to measure O

; high-sensitivity measurements, where appropriate, of CO, SO

, and total reactive nitrogen (NO

); PM

2.5

with both a Federal reference method (FRM) and a continuous monitor, PM

2.5

chemical speciation, and PM

10-2.5

with a continuous FEM; and meteorological measurements of temperature, wind speed, wind direction, and relative humidity. High-sensitivity measurements are necessary for CO, SO

, and NO

to adequately measure a signal for these pollutants in most air sheds for data purposes beyond NAAQS attainment determinations. For the other listed pollutants, conventional ambient air monitoring methods could be used.

At least one NCore station would be required in each State, unless a State determines through the network design process that a site which meets their obligation can be reasonably represented by a site in a second State, and the second State has committed to establishing and operating that site. Any State, local, or tribal agency could propose modifications to these requirements for approval by the Administrator. While the proposed amendments do not specify the cities in which the States must place their multipollutant NCore Level 2 monitoring stations, EPA anticipates that the overall result will be a network that has a diversity of locations to support the purposes listed earlier. For example, there would be sites with different levels and compositions of PM

2.5

and PM

10-2.5

, allowing air quality strategies to be evaluated under a range of conditions.

These sites would be located in a manner that represents as large an area of relatively uniform land use and ambient air concentrations as possible (i.e., out of the area of influence of specific local sources, unless exposure to the local source(s) is typical of exposures across the urban area). Neighborhood-scale sites may be appropriate for multipollutant NCore monitoring stations in cases where the site is expected to be similar to many other neighborhood scale locations throughout the area. In some instances, State and local agencies may have a long-term record of several measurements at an existing location that deviates from the siting criteria in the proposed amendments. The State or local agency may propose utilizing these kinds of sites as the multipollutant NCore monitoring station to take advantage of that record. The EPA will approve these sites, considering both existing and expected new users of the data. The multipollutant NCore stations should be collocated, when appropriate, with other multipollutant air monitoring stations including PAMS, National Air Toxic Trends Station (NATTS) sites, and the PM

2.5

chemical Speciation Trends Network (STN) sites. Collocation would allow use of the same monitoring platform and equipment to meet the objectives of multiple programs where possible and advantageous.

The proposed amendments would require operation of the 60 NCore

stations by January 1, 2011. However, up to 35 of these stations are already being operated on a voluntary and EPA-funded basis with acquisition of high-sensitivity monitors for CO, SO

, and NO

. These three new measurements and other existing measurements for O

,PM

2.5

, and meteorology are the foundation of this highly leveraged network. PM

10-2.5

measurements would also be added to these stations once the continuous technologies are approved as FEM and are commercially available.

Once these multipollutant NCore stations are established, it is EPA's intention that they operate for many years in their respective locations. Therefore, State and local agencies are encouraged to insure long-term accessability to the sites proposed for NCore monitoring stations. Relocating these stations would require EPA approval, which would be based on the data needs of the host State and other clients of the information.

We may negotiate with some States, and possibly with some Tribes, for the establishment and operation of some additional rural NCore multipollutant monitoring stations to complement the multipollutant stations that would be required by the proposed changes to the monitoring regulations. We are in the process of revising CASTNET to upgrade its monitoring capabilities to allow it to provide even more useful data to multiple data users. We expect that about 20 CASTNET sites will have new capabilities at least equivalent to the capabilities envisioned for NCore multipollutant sites. Those sites would reduce the number of, and complement, rural multipollutant sites funded with limited State/local grant funds.

2. Proposed Monitoring Requirements for the Proposed Primary National Ambient Air Quality Standard for PM

10-2.5

The EPA is proposing elsewhere in today's

Federal Register

a new primary standard for coarse particulate matter (PM), and a new indicator for that standard: PM

10-2.5

, qualified so as to include any mix of PM

10-2.5

dominated by resuspended dust from high-density traffic on paved roads and PM generated by industrial sources and construction sources, and excludes any ambient mix of PM

10-2.5

that is dominated by rural windblown dust and soils and PM generated by agricultural and mining sources. See section III.D of the 40 CFR part 50 proposal.

As explained in section III of the NAA

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