PM2.5 and PM10 Hot-Spot Analyses in Project-Level Transportation Conformity Determinations for the New PM2.5 and Existing PM10 National Ambient Air Quality Standards

Federal RegisterMar 10, 2006

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 93

[EPA-HQ-OAR-2003-0049, FRL-8039-5]

RIN 2060-AN02

2.5

and PM

Hot-Spot Analyses in Project-Level Transportation Conformity Determinations for the New PM

2.5

and Existing PM

National Ambient Air Quality Standards

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

This final rule establishes the criteria for determining which transportation projects must be analyzed for local particle emissions impacts in PM

2.5

and PM

nonattainment and maintenance areas. This rule establishes requirements in PM

2.5

areas and revises existing requirements in PM

areas. If required, an analysis of local particle emissions impacts is done as part of a transportation project's conformity determination. EPA is requiring a local particle emissions impacts analysis for certain transportation projects to ensure that these projects do not adversely impact the national ambient air quality standards and human health. The Clean Air Act requires federally supported highway and transit projects to be consistent with (“conform to”) the purpose of a state air quality implementation plan. EPA has consulted with the Department of Transportation (DOT) on the development of this final rule, and DOT concurs with its content.

DATES:

The final rule is effective April 5, 2006, for good cause found as explained in this rule.

ADDRESSES:

EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2003-0049. All documents in the docket are listed on the

http://www.regulations.gov

Web site. Although listed in the index, some information may not be publicly available,

e.g.

, Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through

http://www.regulations.gov

or in hard copy at the Air 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:

Meg Patulski, Transportation and Regional Programs Division, Office of Transportation and Air Quality, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105, telephone number: (734) 214-4842, fax number: (734) 214-4052, e-mail address:

patulski.meg@epa.gov

; or Rudy Kapichak, Transportation and Regional Programs Division, Office of Transportation and Air Quality, U.S. Environmental Protection Agency, 2000 Traverwood Road, Ann Arbor, MI 48105, telephone number: (734) 214-4574, fax number: (734) 214-4052, e-mail address:

kapichak.rudolph@epa.gov

SUPPLEMENTARY INFORMATION:

The contents of this preamble are listed in the following outline:

I. General Information

II. Background

III. PM

2.5

Hot-spot Analyses

IV. PM

Hot-spot Analyses

V. Projects of Air Quality Concern and General Requirements for PM

2.5

and PM

Hot-spot Analyses

VI. Timing of Quantitative PM

2.5

and PM

Hot-spot Analyses and Development of Future Guidance

VII. Categorical PM

2.5

and PM

Hot-spot Findings

VIII. Minor Change for Exempt Projects Regarding Compliance With PM

2.5

SIP Control Measures

IX. How Does Today's Final Rule Affect Conformity SIPs?

X. Statutory and Executive Order Reviews

I. General Information

A. Does This Action Apply to Me?

Entities potentially regulated by the transportation conformity rule are those that adopt, approve, or fund transportation plans, programs, or projects under title 23 U.S.C. or title 49 U.S.C. Regulated categories and entities affected by today's action include:

Category

Examples of regulated entities

Local government

Local transportation and air quality agencies, including metropolitan planning organizations (MPOs).

State government

State transportation and air quality agencies.

Federal government

Department of Transportation (Federal Highway Administration (FHWA) and Federal Transit Administration (FTA)).

This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this final rule. This table lists the types of entities of which EPA is aware that potentially could be regulated by the conformity rule. Other types of entities not listed in the table could also be regulated. To determine whether your organization is regulated by this action, you should carefully examine the applicability requirements in 40 CFR 93.102. If you have questions regarding the applicability of this action to a particular entity, consult the persons listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

B. How Can I Get Copies of This Document?

1. Docket

EPA has established an official public docket for this action under Docket ID No. EPA-HQ-OAR-2003-0049. The official public docket consists of the documents specifically referenced in this action, any public comments received, and other information related to this action. Although a part of the official docket, the public docket does not include Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The official public docket is the collection of materials that is available for public viewing at the Air Docket in the EPA Docket Center. See the

ADDRESSES

section above. You may have to pay a reasonable fee for copying docket materials.

2. Electronic Access

You may access this

Federal Register

document electronically through EPA's transportation conformity Web site at

http://www.epa.gov/otag/transp/tragconf.htm.

You may also access this document electronically under the “Federal Register” listings at

http://www.epa.gov/fedrgstr/.

An electronic version of the public docket is available through the Federal Docket Management System (FDMS), located at

http://www.regulations.gov.

You may use the FDMS to view public comments, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available

electronically. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in B.1. of this section. Once in the FDMS electronic docket system, select “Advanced Search-Docket Search,” then enter the appropriate docket identification number (which is EPA-HQ-OAR-2003-0049) in the “docket ID” field and click “submit”.

II. Background

A. What Is Transportation Conformity?

Transportation conformity is required under Clean Air Act section 176(c) (42 U.S.C. 7506(c)) to ensure that federally supported highway and transit project activities are consistent with (“conform to”) the purpose of the state air quality implementation plan (SIP). Conformity currently applies to areas that are designated nonattainment, and those redesignated to attainment after 1990 (“maintenance areas” with plans developed under Clean Air Act section 175A) for the following transportation-related criteria pollutants: Ozone, particulate matter (PM

2.5

and PM

carbon monoxide (CO), and nitrogen dioxide (NO

). Conformity to the purpose of the SIP means that transportation activities will not cause new air quality violations, worsen existing violations, or delay timely attainment of the relevant national ambient air quality standards (NAAQS or “standards”).

Section 93.102(b)(1) of the conformity rule defines PM

2.5

and PM

as particles with an aerodynamic diameter less than or equal to a nominal 2.5 and 10 micrometers, respectively.

B. What Is the History of the Transportation Conformity Rule?

EPA's transportation conformity rule establishes the criteria and procedures for determining whether transportation activities conform to the SIP. EPA first promulgated the transportation conformity rule on November 24, 1993 (58 FR 62188), and subsequently published a comprehensive set of amendments on August 15, 1997 (62 FR 43780) that clarified and streamlined language from the 1993 rule. EPA has made other smaller amendments to the rule both before and after the 1997 amendments.

More recently, on July 1, 2004, EPA published a final rule (69 FR 40004) that amended the conformity rule to accomplish three objectives. The final rule:

• Provided conformity procedures for state and local agencies under the new ozone and PM

2.5

air quality standards;

• Incorporated existing EPA and DOT federal guidance into the conformity rule consistent with a March 2, 1999 U.S. Court of Appeals decision; and

• Streamlined and improved the conformity rule.

The July 1, 2004 final rule incorporated most of the provisions from the November 5, 2003 proposal for conformity under the new ozone and PM

2.5

standards (68 FR 62690). EPA is conducting its conformity rulemakings in the context of EPA's broader strategies for implementing the new ozone and PM

2.5

standards.

Finally, on May 6, 2005, EPA promulgated a final rule entitled, “Transportation Conformity Rule Amendments for the New PM

2.5

National Ambient Air Quality Standard: PM

2.5

Precursors” (70 FR 24280). This final rule specified the transportation-related PM

2.5

precursors and when they apply in transportation conformity determinations in PM

2.5

nonattainment and maintenance areas.

C. Why Are We Issuing This Final Rule?

In the November 2003 proposal, EPA presented two options concerning hot-spot analyses in PM

2.5

and PM

nonattainment and maintenance areas. EPA received substantial comment on this portion of the November 2003 proposal. After considering these comments, EPA, in consultation with the U.S. Department of Transportation (DOT), issued a supplemental notice of proposed rulemaking on December 13, 2004 (69 FR 72140) which requested further public comment on additional options for PM

2.5

and PM

hot-spot requirements and those options presented in the original November 2003 proposal. In developing today's final rule, EPA considered all of the comments received on PM

2.5

and PM

hot-spot analysis requirements both in response to the original November 2003 proposal as well as the December 2004 supplemental proposal. EPA received over 5,400 sets of comments on the two proposals from state and local transportation and air quality agencies, environmental groups, transportation advocates, and the general public.

EPA has consulted with DOT, our Federal partner in implementing the transportation conformity regulation, in developing the final rule, and DOT concurs with its content. Please see Sections III. and IV. for more information regarding how this final rule impacts project-level conformity determinations in PM

2.5

and PM

areas, including those for projects that are currently under development.

III. PM

2.5

Hot-spot Analyses

A. Background

1. What Is a Hot-spot Analysis?

A hot-spot analysis is defined in 40 CFR 93.101 as an estimation of likely future localized pollutant concentrations resulting from a new transportation project and a comparison of those concentrations to the relevant air quality standard. A hot-spot analysis assesses the air quality impacts on a scale smaller than an entire nonattainment or maintenance area, including, for example, congested roadway intersections and highways or transit terminals. Such an analysis is a means of demonstrating that a transportation project meets Clean Air Act conformity requirements to support state and local air quality goals with respect to potential localized air quality impacts.

Prior to today's final rule, the conformity rule required some type of hot-spot analysis for all FHWA and FTA funded or approved non-exempt transportation projects in CO and PM

nonattainment and maintenance areas (40 CFR 93.116 and 93.123). This requirement applied for all project-level conformity determinations that occur both before and after a SIP is submitted for the CO or PM

air quality standards.

EPA established the type of hot-spot analysis—either quantitative or qualitative—based on the potential impact of a given project or project location on the air quality standards, so that more rigorous quantitative analyses are only required when necessary to meet statutory requirements. Since the original November 24, 1993 conformity rule, EPA has required quantitative analyses for projects that have the highest potential to impact the CO air quality standards (

i.e.

, “projects of air quality concern”). The conformity rule also has detailed projects that have the highest potential to impact the PM

standards, including new or expanded bus and rail terminals or transfer points involving diesel vehicles. These projects of air quality concern would be subject to quantitative hot-spot analyses once the tools and EPA's future modeling guidance are available. In contrast, more streamlined, qualitative hot-spot analyses have been required for all other projects.

Such a tiered approach was intended to utilize state and local resources in an efficient manner while meeting statutory requirements. Quantitative hot-spot analyses use dispersion modeling to determine the potential air quality impact of motor vehicle emissions associated with a highway or

transit project. Qualitative hot-spot analyses involve more streamlined reviews of local factors such as local monitoring data near a proposed project.

EPA notes, however, that quantitative PM

hot-spot analyses have not yet been required for projects of air quality concern due to a lack of EPA modeling guidance and appropriate methods. Section 93.123(b)(4) of the conformity rule states that the requirements for quantitative PM

hot-spot analyses will not take effect until EPA releases modeling guidance and announces in the

Federal Register

that these requirements are in effect, which EPA has not yet done.

Today's final rule does not impact the existing CO hot-spot requirements; however, the final rule revises the PM

hot-spot requirements as discussed in Sections IV. and V.

2. Proposed Options

EPA proposed several options for how PM

2.5

hot-spot requirements would apply for project-level conformity determinations in PM

2.5

nonattainment and maintenance areas. In general, these options were proposed to apply during the time periods before and after a PM

2.5

SIP is submitted. EPA is repeating in today's action the descriptions of the previously proposed options to assist in discussing the final rule and responses to comments. EPA noted in its proposals that hot-spot analyses would be based only on directly emitted PM

2.5

attributable to an individual transportation project, since secondary particles formed through PM

2.5

precursors take several hours to form in the atmosphere, giving emissions time to disperse beyond the immediate area of concern for localized analyses.

The following five options were proposed for PM

2.5

hot-spot requirements for individual projects in PM

2.5

areas prior to the submission of a PM

2.5

SIP (December 13, 2004, 69 FR 72144):

•

Options 1 and 2:

Do not apply any PM

2.5

hot-spot analysis requirements for any PM

2.5

area before the submission of the PM

2.5

SIP

;

Options 1 and 2 were originally proposed in the November 5, 2003 notice as well (68 FR 62712). Option 1 would have not required any PM

2.5

hot-spot requirement at any time before or after a PM

2.5

SIP is submitted. Option 2 also would not require PM

2.5

hot-spot analyses prior to a PM

2.5

SIP submission, and then only if the SIP identified types of projects or locations of air quality concern for a given area.

•

Option 3:

Apply the existing conformity rule's PM

hot-spot analysis requirements with respect to PM

2.5

in all PM

2.5

areas;

•

Option 4:

Apply the existing conformity rule's PM

hot-spot analysis requirements with respect to PM

2.5

, unless the EPA Regional Administrator or state air agency finds that localized PM

2.5

violations are not a concern for a given PM

2.5

area; or

•

Option 5:

Apply the existing conformity rule's PM

hot-spot analysis requirements with respect to PM

2.5

, only if the EPA Regional Administrator or state air agency finds that localized PM

2.5

violations are a concern for a given PM

2.5

area.

EPA proposed that an EPA or state air agency finding under Options 4 and 5 that PM

2.5

localized violations are or are not a concern prior to PM

2.5

SIP submission would be based on a case-by-case review of local factors for a given PM

2.5

area. EPA requested information from commenters about whether sufficient local information was available to make such findings.

EPA also proposed three options for project-level conformity determinations after the submission of a PM

2.5

SIP (December 13, 2004, 69 FR 72145):

•

Option A:

Do not apply any PM

2.5

hot-spot analysis requirements for any PM

2.5

area (

i.e.

, Option 1 from the November 2003 proposal);

•

Option B:

Only require quantitative PM

2.5

hot-spot analyses for projects at those types of locations that the PM

2.5

SIP identifies as a localized PM

2.5

air quality concern for a given area (

i.e.

, Option 2 from the November 2003 proposal). No quantitative or qualitative analyses would be required for any projects in other types of locations, or in PM

2.5

areas where the SIP does not identify types of locations as a localized PM

2.5

air quality concern; or

•

Option C:

Apply the existing conformity rule's PM

hot-spot analysis requirements with respect to PM

2.5

for all projects in PM

2.5

areas, with a minor addition.

Under Option C, EPA proposed to add a new criterion that would require that quantitative analyses also be performed at those types of project locations that the PM

2.5

SIP identifies as a PM

2.5

hot-spot concern. See the November 5, 2003 proposal (68 FR 62712-62713) and the December 13, 2004 supplemental proposal (69 FR 72144-72149) for further information on all of the proposed options.

For options involving hot-spot analyses, EPA proposed to not require quantitative PM

2.5

hot-spot analyses until EPA releases its future modeling guidance, consistent with the existing provision for PM

analyses in § 93.123(b)(4). EPA also proposed to extend to PM

2.5

areas the existing conformity rule's flexibility in § 93.123(b)(3) for DOT to make categorical hot-spot findings to further streamline analysis requirements when modeling shows that additional analyses are not necessary to meet Clean Air Act requirements for a given project.

Last, EPA requested comments on all of the proposed options, and invited commenters to submit any data or other information about the proposed options, including whether state and local agencies would have information available for implementation. In developing this final rule, EPA considered all of the comments and information submitted for the November 2003 and December 2004 proposals. The December 2004 supplemental proposal also included proposed regulatory text that combined various PM

2.5

and PM

hot-spot options as illustrative examples, and EPA noted that any combination of the proposed PM

2.5

or PM

hot-spot options could be included in the final rule.

B. Description of Final Rule

In summary, EPA is finalizing a hybrid of some of the proposed options by:

Being generally consistent with Options 3 (for the period before a SIP is submitted) and C (for the period after a SIP is submitted) for projects of localized air quality concern, and

• Providing the flexibility from other proposed options to eliminate qualitative hot-spot analyses for all projects not of air quality concern.

The final rule requires quantitative PM

2.5

hot-spot analyses only for projects of air quality concern, and qualitative hot-spot analyses would be done for these projects before EPA releases its future modeling guidance and announces that quantitative PM

2.5

hot-spot analyses are required under § 93.123(b)(4). EPA specifies in § 93.123(b)(1) that projects of air quality concern are highway and transit projects that involve significant levels of diesel vehicle traffic, or any other project that is identified in the PM

2.5

SIP as a localized concern.

EPA considered several factors in focusing on projects involving significant numbers of diesel vehicles in developing today's final rule. For example, PM

2.5

and PM

diesel emission factors are significantly higher than gasoline vehicles on a per-vehicle basis. In addition, studies in proximity of vehicular traffic tend to show that elevated PM

2.5

concentrations occur near diesel vehicle operations, but show less consistent evidence near locations with high gasoline vehicle operations. See Section V. for more information regarding how and why EPA defined projects of air quality concern in the final rule.

Today's final rule does not require any hot-spot analysis—qualitative or quantitative—for projects that are not listed in § 93.123(b)(1) as an air quality concern. These projects are presumed to meet Clean Air Act requirements and 40 CFR 93.116 without any explicit hot-spot analysis for the reasons explained in full below. State and local project sponsors should briefly document in their conformity documentation for such projects that an explicit PM

2.5

hot-spot analysis was not completed because Clean Air Act and 40 CFR 93.116 requirements were met without an explicit PM

2.5

hot-spot analysis.

This final rule requires PM

2.5

hot-spot analyses for projects of air quality concern in PM

2.5

nonattainment and maintenance areas at all times—both before and after a PM

2.5

SIP is submitted. EPA had distinguished its proposed options for the time periods before and after PM

2.5

SIPs are submitted, but for reasons discussed further below, this type of specificity is no longer necessary. Projects of air quality concern are anticipated to have the potential to increase local PM

2.5

concentrations, and as a result, PM

2.5

hot-spot analyses are needed for such projects to ensure that the local air quality impacts of such projects are considered prior to receiving federal funding or approval. EPA is finalizing specific criteria about the types of projects that require such analyses, based on our November 2003 and December 2004 proposals and comments received. See Section V. of this notice for further details regarding the regulatory criteria for projects of air quality concern and more information on the general requirements for performing hot-spot analyses.

In addition, the final rule allows DOT, in consultation with EPA, to make categorical hot-spot findings that would further streamline quantitative hot-spot analysis requirements in appropriate cases in PM

2.5

areas, as the existing conformity rule already allows in PM

areas for some projects. A categorical hot-spot finding would be made if there is appropriate modeling that shows that a particular category of highway or transit projects of air quality concern meet statutory requirements without additional quantitative hot-spot modeling for such types of projects individually. See Section VII. for further details regarding categorical hot-spot findings.

This final rule requires a qualitative PM

2.5

hot-spot analysis to be completed for project-level conformity determinations for projects of air quality concern completed in PM

2.5

nonattainment areas on or after April 5, 2006, when PM

2.5

conformity requirements apply.

Quantitative analyses are not required for these projects at this time since EPA is not requiring quantitative PM

2.5

hot-spot analyses under § 93.123(b)(4) since quantitative hot-spot modeling techniques and associated EPA modeling guidance still do not exist. Qualitative PM

2.5

hot-spot analyses should be completed according to joint EPA and DOT guidance. This guidance was developed in consultation with DOT, and the guidance will be posted on the Web site provided in Section I.B.2. of today's notice. See Section VI. of this final rule for more information regarding the timing of EPA's future quantitative hot-spot modeling guidance and subsequent application of quantitative requirements.

On January 5, 2005 (70 FR 943), EPA designated areas as attainment and nonattainment for the PM

2.5

standards. These designations became effective on April 5, 2005. As a result, conformity for the PM

2.5

standards will apply to newly designated nonattainment areas on April 5, 2006.

Finally, EPA notes that its future quantitative hot-spot modeling guidance will also address how the current 24-hour and annual PM

2.5

air quality standards are to be considered in quantitative hot-spot analyses. The Clean Air Act and conformity rule require that conformity be met for both the 24-hour and annual PM

2.5

air quality standards in all PM

2.5

nonattainment and maintenance areas. However, transportation plan and transportation improvement program (TIP) conformity determinations and regional emissions analyses could address only one PM

2.5

standard if meeting conformity for the controlling standard would ensure that Clean Air Act requirements are met for both standards. EPA will address how PM

2.5

hot-spot analyses should consider both applicable PM

2.5

standards in our future quantitative hot-spot modeling guidance. This future guidance will be consistent with how potential impacts on the PM

2.5

standards are being considered in EPA's rulemaking for the PM

2.5

implementation strategy, which EPA proposed on November 1, 2005 (70 FR 66040). Quantitative hot-spot analyses for conformity purposes would consider how projects of air quality concern are predicted to impact air quality at existing and potential PM

2.5

monitor locations which are appropriate to allow the comparison of predicted PM

2.5

concentrations to the current PM

2.5

standards, based on PM

2.5

monitor siting requirements (40 CFR part 58). EPA developed these monitor siting requirements to determine the level of protection of community public health provided by the current PM

2.5

standards.

C. Rationale

In its December 2004 supplemental proposal, EPA stated that several factors needed to be considered for establishing a PM

2.5

hot-spot requirement. Those factors are as follows:

• The Clean Air Act conformity requirements for individual transportation projects;

• The current scientific understanding of PM

2.5

hot-spots and public health effects;

• The feasibility of implementing a PM

2.5

hot-spot requirement; and

• The impact on state and local resources.

The following paragraphs outline how EPA considered these factors in the final rule.

Clean Air Act legal requirements:

EPA believes that the final rule allows all federally funded and approved transportation projects in PM

2.5

areas to meet applicable statutory requirements. Clean Air Act section 176(c)(1)(B) is the statutory criterion that must be met by all projects in nonattainment and maintenance areas that are subject to transportation conformity. Section 176(c)(1)(B) states that federally-supported transportation projects must not “cause or contribute to any new violation of any standard in any area; increase the frequency or severity of any existing violation of any standard in any area; or delay timely attainment of any standard or any required interim emission reductions or other milestones in any area.” The Clean Air Act requires that these provisions be met for all FHWA or FTA funded or approved projects, except traffic signal synchronization projects; it does not distinguish that these requirements apply based on whether or not a SIP has been submitted. Through previous rulemaking, EPA has determined that the exempt projects listed in 40 CFR 93.126 have met section 176(c)(1)(B) without further hot-spot analyses. Through today's action, EPA is determining that projects not identified in the rule as projects of air quality concern have also met section 176(c)(1)(B) without further hot-spot analyses. The final rule requires that all projects of air quality concern be analyzed for localized impacts, regardless of whether or not the PM

2.5

SIP is submitted.

EPA continues to believe it has discretion to establish the level and form of PM

2.5

analysis that is necessary to meet Clean Air Act section 176(c) statutory requirements. Therefore, EPA is finalizing criteria for when PM

2.5

hot-spot analyses are required based on scientific information available on PM

2.5

hot-spots and emissions from diesel vehicles, and the Agency's experience in implementing CO and PM

hot-spot requirements since 1993 for what level of analysis is appropriate and worthwhile. The final rule's criteria for what projects require hot-spot analyses will ensure that all projects that have the potential to impact the air quality standards will be analyzed using appropriate methods before they receive Federal funding or approval. The final rule includes criteria for what projects of air quality concern require quantitative PM

2.5

analyses based on existing scientific information and comments received, as discussed further in this section and in Section V.

Furthermore, EPA is changing its precedent to date in no longer requiring qualitative hot-spot analyses for projects that are not of localized air quality concern. As stated previously, since the original 1993 conformity rule, some type of hot-spot analysis has been required to meet statutory requirements for all non-exempt FHWA and FTA projects in PM

nonattainment and maintenance areas. However, based on the history of implementation of this provision over the past ten plus years, as explained in more detail below, EPA now believes that these projects which do not represent a localized air quality concern can be presumed to meet Clean Air Act requirements and 40 CFR 93.116 without any explicit hot-spot analysis.

Requiring qualitative hot-spot analyses for projects that are not an air quality concern is also not a beneficial use of Federal, state, or local resources. EPA is basing this conclusion in part on a recent review by EPA and DOT field offices of project-level conformity determinations involving historical qualitative hot-spot analyses in PM

areas. This review did not find any qualitative hot-spot analysis in a PM

nonattainment or maintenance area where it was determined that Clean Air Act requirements were not met. In other words, qualitative hot-spot analyses for projects that are not an air quality concern in PM

areas did not result in any predicted new or worsened air quality violations.

In addition, EPA and DOT offices evaluated whether any mitigation measures had been added to a project in response to a PM

qualitative hot-spot analyses. Mitigation measures are sometimes used to reduce project emissions and any impact on local air quality, so that a project can demonstrate conformity. Whatever the case, the EPA and DOT field offices did not identify any cases where any mitigation measures were added to reduce emissions from implemented projects to meet statutory conformity requirements. EPA found in its review of previous qualitative PM

hot-spot analyses that mitigation measures were added in some cases to reduce fugitive dust emissions during project construction (e.g., slope covering, street sweeping, use of water, quarry spalls). However, these measures were added for other mitigation purposes during the construction phase of a project, rather than to meet conformity requirements for the time period when construction is completed and a project is open to traffic. EPA has included a summary of its review in the docket for this rulemaking.

For all of these reasons and since EPA does not expect these projects to ever impact the PM

2.5

standards, EPA has not finalized any hot-spot analysis requirement for projects that are not an air quality concern. EPA concludes that since no such projects will have localized air quality impacts of concern, all such projects can meet statutory conformity requirements without an explicit hot-spot analysis.

However, as noted elsewhere in today's action, EPA is finalizing a qualitative PM

2.5

hot-spot requirement for projects of air quality concern prior to quantitative guidance and models being available. EPA believes that there is value in federal, state, and local agencies and the general public discussing the localized air quality impacts of a project of air quality concern, even if such reviews can only be qualitative in nature at this time. This aspect of the final rule is intended to be an environmentally conservative approach to meeting Clean Air Act requirements in the time period before quantitative hot-spot modeling techniques and future guidance is available for projects of localized air quality concern.

Scientific understanding of potential for transportation-related PM

2.5

hot-spots:

Another critical factor for developing the final rule is whether or not transportation projects have the potential to affect the PM

2.5

standards in local areas. Understanding whether or not an individual transportation project can result in a PM

2.5

hot-spot and if so, under what circumstances, provides a basis for considering whether explicit hot-spot analyses must be required for conformity purposes, and if so for which types of projects or potential project locations.

As discussed above, EPA believes that highway and transit projects that involve significant levels of diesel vehicle emissions have the potential to increase local PM

2.5

concentrations. As a result, PM

2.5

hot-spot analyses are needed to ensure that the local air quality impacts of such projects are considered prior to receiving Federal funding or approval. This finding is based on EPA's thorough review of existing scientific papers as well as additional technical and anecdotal information that was submitted by state and local agencies during the rulemaking process. All of this information is contained in the docket for this rulemaking.

In developing the final rule, EPA completed a thorough review of more than 70 studies representing a cross-section of available studies looking at particle concentrations near roadways. Some of these studies were considered for our previous proposals; others were newly considered for the final rule. Some of these studies are discussed in today's action; all studies are included in the docket for this final rule.

EPA believes that these studies provide strong evidence of elevated PM

2.5

concentrations along roadways on a consistent basis from certain types of projects. Based on EPA's review of all studies, studies identified elevated PM

2.5

concentrations of 8% to 60% for high-traffic roadways to 285% for major truck stops, compared to background concentrations. Variables identified in the studies as key predictors of PM

2.5

concentrations include: Total traffic volume; volume of heavy-duty trucks; traffic congestion; and proximity to major facilities (within approximately 150 meters). Most studies showed elevation in PM

2.5

, black carbon, or other components

associated with major facilities (e.g., truck routes, intermodal or bus terminals). Several showed no elevation in PM

2.5

per se, but did show elevation in black carbon, particle number, or some other component of PM

2.5

. Only one study showed no elevation in any component of PM

2.5

close to roadways.

Examples of other components that are considered PM

2.5

include organic carbon and particle-phase polycyclic aromatic hydrocarbons.

Overall, major conclusions from these studies are:

• Black/elemental carbon (BC or EC) mass concentrations and particle number (e.g., “ultrafines”) concentrations are consistently associated with proximity to traffic (generally within 150 meters).

• PM

2.5

is associated with proximity to traffic in most, but not all cases.

• Both regional background and local sources contribute to site-specific PM

2.5

concentrations.

• The “near-roadway increment” of PM

2.5

tends to be comprised of approximately 50-80% black or

elemental carbon (indicating mobile sources are a key source).

Some examples of the types of studies we examined include Lena

et al.

(2002), where investigators from Columbia University conducted a community-based study in a neighborhood of the South Bronx, NY, with heavy freight traffic. Vehicle counts and EC concentrations were monitored over a 10-12 hour period at several sites along designated truck routes and other neighborhood sites. Within the neighborhood, EC was 20-28% of ambient PM

2.5

along truck routes, but only 13-16% at non-trucks sites. Trucks were estimated to contribute between 5.0-14.2 μg/m

2.5

, depending on the level of truck traffic.

In a study by Indale (2004), investigators from the University of Tennessee-Knoxville and Oak Ridge National Laboratory conducted air quality monitoring and modeling at a large truck stop along a freight corridor outside Knoxville, TN. Continuous PM

2.5

and NO

monitoring took place between December 2003 and September 2004. Monthly-averaged PM

2.5

ranged from 27-40 μg/m

within the truck stop, with the 98th percentile of daily values exceeding 65 μg/m

. Regional background PM

2.5

during the same interval was only 14 μg/m

. PM

2.5

and NO

concentration within the truck stop tracked the number of idling trucks within the truck stop closely, which was highest at night. Hourly PM

2.5

concentrations within the truck stop averaged 10 μg/m

greater than along the interstate highway 200 meters distant. EPA notes that the findings of this study are more relevant to how PM

2.5

air quality would be affected by freight or bus terminals, as opposed to highway facilities servicing truck routes.

Finally, in Brauer

et al.

(2003), investigators obtained “annualized” average PM

2.5

and black carbon at 40-42 locations in each of three locations: The Netherlands (nationwide), Stockholm County (Sweden), and Munich, Germany. Monitoring consisted of samples taken 15 minutes of every hour over 4 two-week periods throughout a 17-month period, normalized to a central monitor. Locations consisted of “traffic” sites (>3,000 vehicles/day within a 50 m radius), “urban background” sites, and rural sites. PM

2.5

was 8-35% higher, and black carbon was 43-84% higher at “traffic” sites than at “urban background” sites. Using regression within each area of study, traffic intensity on roads within 250 meters explained 30-40% of the variability in PM

2.5

, and 54-70% of variability in black carbon. Traffic was the strongest explanatory variable in all statistical models.

EPA notes that its understanding of the potential for PM

2.5

hot-spots from transportation projects has evolved over the past three years. In the November 2003 proposal (68 FR 62713), EPA proposed options that would have required no PM

2.5

hot-spot analyses, or only analyses in limited cases—which reflected its understanding at that time of the limited potential for transportation-related PM

2.5

hot-spots. Most of the research studies that had been reviewed by late 2003 indicated that concentrations of some components of PM

2.5

increased near heavily traveled roadways. EPA considered at that time that many of these studies did not measure PM

2.5

directly, but rather, considered concentrations of some components of PM

2.5

, such as BC and ultrafine particles.

In proposing additional options in the December 2004 supplemental proposal after receiving public comment, EPA considered additional studies and reconsidered some of its previous statements from the November 2003 proposal. For example, EPA now believes that the information considered in the November 2003 proposal as well as the most recent information available does indicate a potential for higher localized emissions and PM

2.5

concentrations near certain transportation facilities. Since November 2003, EPA has considered how information underlying previous statements was developed, including how localized emissions increases and existing background concentrations relate to the potential for localized violations of the PM

2.5

standards.

Furthermore, EPA had stated in the November 2003 proposal that PM

2.5

monitoring data available at that time indicated that PM

2.5

air quality problems were similar to ozone in that they are both primarily regional in nature, which the Agency now believes was an incomplete assessment of the broader PM

2.5

air quality problem. EPA now believes that PM

2.5

is both a regional and a localized air quality concern in certain circumstances. While it is true that secondary formation from PM

2.5

precursors is a critical component to the regional PM

2.5

air quality problem, directly emitted PM

2.5

from certain local sources has the potential to cause or contribute to elevated localized PM

2.5

concentrations. Such elevated concentrations which exceed applicable standards can have an effect on local communities and populations that the PM

2.5

standards were designed to protect.

In the December 2004 supplemental proposal, EPA considered additional scientific studies and requested public comment on our assessments of such studies. For example, EPA highlighted a new study, Burr,

et al.,

(2004), which examined changes in traffic patterns associated with a single transportation project that can result in statistically significant differences in PM

2.5

mass concentrations measured along affected roadways. The results of this study highlight changes in PM

2.5

concentrations along roadways resulting from changes in local traffic patterns, rather than changes in regional PM

2.5

emissions.

While originally believed to be a predominantly regional pollutant, subsequent analyses of EPA's PM

2.5

monitoring data reveal the influence of both regional and local sources. Pinto

et al.

(2004) reviewed monitoring data from 1999 to 2001 from 27 urban areas nationally. This study showed that differences in annual means between monitors within a city often reached 5 μg/m

or higher, reflecting the possible influence of local sources in many areas, in addition to variations in meteorology and terrain. Although this study does not specifically address transportation sources, the study highlights the importance of subregional sources that impact local PM

2.5

air quality.

Finally, EPA has considered all of the information that commenters have provided in response to the November 2003 and December 2004 proposals. EPA received a range of information from commenters, such as:

• Broad observations for targeting PM

2.5

hot-spot requirements;

• General discussions about monitoring data gathered to date on PM

2.5

hot-spots;

• Narrative, non-technical descriptions of an individual PM

2.5

area's considerations for potential PM

2.5

hot-spots;

• Examples of state and local regulations that target potential PM

2.5

hot-spots from transportation projects; and,

• Plans by individual states and nonattainment areas to conduct studies on the existence of PM

2.5

hot-spots.

This and other information received from commenters is included in the docket for today's final rule. We will further consider these and other state and local information in the development of our future quantitative PM

2.5

hot-spot modeling guidance and implementation for this final rule.

Feasibility and resource implications:

EPA also considered whether or not the final rule's requirements were feasible and practical. For example, is the

information needed to implement an option available? Do state and local agencies have the methods and experience to implement an option in a reasonable time frame? EPA considered these and other questions, so that meeting statutory requirements was assured to be completed in an efficient manner. EPA rejected options that could not be feasibly implemented.

Targeting projects of air quality concern and not requiring qualitative hot-spot analyses for projects that are not of concern will streamline project-level conformity determinations in PM

2.5

areas, since many proposed projects in transportation plans and TIPs are not expected to be of air quality concern. Allowing DOT to make categorical hot-spot findings will provide another opportunity to further narrow the focus of quantitative analyses for those projects that matter significantly for air quality. All of these aspects of the final rule will utilize state and local resources in an efficient and reasonable manner while still satisfying Clean Air Act requirements. See Sections V. and VII. for further rationale and responses to comments on criteria for projects of air quality concern and categorical hot-spot findings.

D. Response to Comments on Proposed PM

2.5

Hot-spot Options

EPA received comments on the proposed options for PM

2.5

areas from state and local transportation and air quality agencies, environmental groups, transportation advocates, and the general public. Certain general trends were evident where the same commenters supported similar options during the time periods before and after a PM

2.5

SIP is submitted. In general, commenters who supported finalizing no or limited PM

2.5

hot-spot requirements prior to PM

2.5

SIP submission (Options 1, 2, or 5) also generally supported options that would have no hot-spot requirement at all (Option A) or rely on the SIP to identify hot-spot requirements (Option B) after PM

2.5

SIP submission. Similarly, commenters who supported applying the existing PM

hot-spot requirements prior to PM

2.5

SIPs (Options 3 or 4), also supported doing the same after PM

2.5

SIPs are in (Option C). In addition, there were commenters who believed either that EPA should delay finalizing a PM

2.5

hot-spot requirement at this time, or that EPA should modify the proposed options so that they are more environmentally protective. The following paragraphs describe these and other comments that EPA considered in the development of the final rule, and EPA's responses to those comments.

Comment

Many commenters supported finalizing PM

2.5

hot-spot requirements that were consistent with the previous conformity rule's provisions for PM

areas (i.e., Options 3 and C), to meet Clean Air Act requirements and protect public health. Commenters supported these options because they believed that these options would promote consistency with EPA's past legal interpretations regarding how federally funded and approved transportation projects met Clean Air Act section 176(c)(1)(B) requirements in PM

areas. Commenters believed that it was reasonable to expect that transportation projects can cause PM

2.5

hot-spots, and that conducting project-level PM

2.5

hot-spot analyses would provide an environmental benefit by characterizing emissions impacts and considering mitigating approaches. These commenters also argued that the available scientific studies and research demonstrate that all transportation projects, including highway and transit projects involving significant diesel traffic, have the potential to create PM

2.5

hot-spots.

EPA also received many comments, including over 5,000 form e-mail comments from private citizens, expressing concerns about many of the proposed options that would require no or limited PM

2.5

hot-spot analyses (e.g., Options 1, 2, 5, A, and B), which they believed did not go far enough in protecting public health. These commenters were very concerned that all transportation projects, especially major highway projects, be evaluated for local PM air quality impacts on people living in neighborhoods before these projects receive Federal approval or funding. The commenters believed that EPA should consider the severity of PM

2.5

impacts on the health and welfare of adults who work, children who play, and families living in neighborhoods near heavily traveled highways. The commenters indicated that these populations are at increased risk of suffering from serious health effects from PM

2.5

, including asthma, heart disease, lung cancer, and associated premature death. Other commenters also cited studies on the serious health effects caused by high PM

2.5

concentrations, and believed that requiring PM

2.5

hot-spot analyses for all projects best protects the public health for citizens in PM

2.5

areas, especially vulnerable populations living near proposed transportation projects.

On the other hand, many other commenters supported options that would apply no or only limited PM

2.5

hot-spot requirements (i.e., Options 1, 2, 5, A, and B), and some preferred that EPA delay issuing final PM

2.5

hot-spot requirements until certain issues are addressed. These commenters believed that there was insufficient evidence regarding the existence and prevalence of PM

2.5

hot-spots. Commenters stated that their preferences would be appropriate because PM

2.5

is a new pollutant that should be further examined at the national and local level before more rigorous PM

2.5

hot-spot requirements are finalized. Some commenters argued that PM

2.5

hot-spot requirements are not required by the Clean Air Act at all, and therefore, no such requirements should ever be finalized in EPA regulations.

Other commenters were opposed to requiring existing PM

hot-spot requirements in PM

2.5

areas (under Options 3 and C) because they believed these options would require extensive analyses without comparable environmental benefits and flexibility. These commenters believed it was unnecessary and excessive to require hot-spot analyses for every project in every PM

2.5

nonattainment area. Commenters argued that more research is needed to better define the situations where hot-spots may be a concern, and how individual projects could impact air quality standards under different air quality circumstances. Some of these commenters also argued that EPA has not demonstrated why performing PM

2.5

hot-spot analyses would be beneficial to attaining the PM

2.5

standards.

Response

EPA believes that the final rule addresses many of the concerns raised by commenters. As described above, EPA concludes that the final rule allows all projects in PM

2.5

areas to meet Clean Air Act section 176(c)(1)(B) requirements during the time periods both before and after a PM

2.5

SIP is submitted. EPA believes that today's final rule is consistent with its past legal interpretations for applying hot-spot requirements for projects of air quality concern.

However, EPA disagrees with commenters who argued that there is not enough information at this time to apply a PM

2.5

hot-spot requirement. Based on our review of scientific studies and information gathered during the rulemaking process, as described above, EPA believes that there is compelling evidence that certain transportation projects of air quality concern have the potential to impact localized PM

2.5

concentrations. Such impacts, if they would create or worsen violations for the PM

2.5

standards on communities

surrounding a project of air quality concern, would be contrary to the Clean Air Act's conformity requirements. Furthermore, EPA does not agree that it is appropriate to delay finalizing a PM

2.5

hot-spot requirement for such projects until certain comments are addressed, for the reasons cited above.

EPA notes again, as described further elsewhere in this notice, that projects which do

not

represent a localized air quality concern can be presumed to meet Clean Air Act requirements and 40 CFR 93.116 without any explicit hot-spot analysis. This aspect of the final rule is expected to streamline PM

2.5

hot-spot requirements and use state and local resources efficiently.

Comment

EPA also proposed Options 2 and B that relied solely on the SIP to identify projects or project locations of potential PM

2.5

hot-spot concern. Under these options, quantitative PM

2.5

hot-spot analyses would only be required at types of project locations identified as a localized air quality concern in a given PM

2.5

SIP. No quantitative or qualitative analyses would be required for projects in other types of locations, or in PM

2.5

areas where the SIP does not identify types of locations as a localized PM

2.5

air quality concern. Furthermore, no hot-spot analyses would be required for any projects in PM

2.5

areas prior to PM

2.5

SIP submission.

Many commenters supported these options. Some commenters believed that the existence and prevalence of PM

2.5

hot-spots was uncertain and that the SIP process could assist in identifying what projects are of concern in a given area and consequently what level of PM

2.5

hot-spot analysis is appropriate. Commenters opined that Options 2 and B would allow each PM

2.5

area to better target potential PM

2.5

hot-spots and protect the public health of their citizens, since the SIP is the appropriate mechanism for addressing state and local air quality goals. These options were considered by some to provide the necessary flexibility in implementing hot-spot requirements both before and after a PM

2.5

SIP is submitted.

In contrast, other commenters believed that Options 2 and B would not meet Clean Air Act requirements or protect public health. First, such commenters indicated that Option 2 would eliminate any requirement to perform PM

2.5

hot-spot analyses prior to the development of a PM

2.5

SIP, which would not meet statutory requirements that apply during this time period. These commenters argued that PM

2.5

emissions impacts resulting from transportation projects should be assessed and mitigated as part of the conformity process at all times, and that such projects if not analyzed could significantly degrade air quality and increase the number and severity of local PM

2.5

violations in the time period prior to SIP submission.

Second, several commenters believed that this option may not be feasible in every area because it is unlikely that there is adequate data to identify exact locations of local concern in the SIP. This could be due to the absence of data or lack of specificity of existing data regarding PM

2.5

hot-spot locations. Some argued that this may be the case due to placement of current monitors away from large transportation projects, or the focus on the annual PM

2.5

standard rather than the 24-hour PM

2.5

standard in SIP development. One commenter believed that PM

2.5

air quality monitors have historically been located more than the 300 feet from where highway projects would have their major impact on PM

2.5

concentrations.

Third, commenters were concerned that Option B would place an inequitable burden on state and local air agencies that are already tasked with developing PM

2.5

SIPs to meet other Clean Air Act requirements. PM

2.5

SIPs are statutorily required to be submitted three years from the effective date of PM

2.5

nonattainment designations (i.e., April 5, 2008). Unless possible PM

2.5

hot-spot locations are well-defined and based on developed and verified monitoring data, one commenter argued, it would be inappropriate at this time to solely rely on PM

2.5

SIPs to implement conformity requirements.

Although two commenters supported the consideration of PM

2.5

hot-spots in the SIP process, they did not agree that solely relying on that process met Clean Air Act conformity requirements, for the reasons described above. In addition, these commenters argued that it is uncertain whether PM

2.5

SIPs will be developed on time, based on past history of SIP submissions.

Finally, some commenters were skeptical regarding whether the SIP process was the appropriate forum for identifying transportation-related hot-spots. These commenters believed that there is no legal obligation under the Clean Air Act to identify project locations of air quality concern in the SIP. They argued that Option B was deficient because states may choose not to identify potential hot-spot locations either because sufficient data is not available or out of concern that conformity requirements would apply. These commenters also believed that air agencies had a poor historical record of developing appropriate PM

SIPs, and that it was unclear whether EPA would be willing or able to remedy any PM

2.5

SIPs that did not identify transportation-related PM

2.5

hot-spot locations.

Response

EPA is not finalizing Options 2 and B because these options do not sufficiently address all of the factors outlined in the December 2004 supplemental proposal and today's final rule:

• The Clean Air Act conformity requirements for individual transportation projects;

• The current scientific understanding of PM

2.5

hot-spots and public health effects;

• The feasibility of implementing options; and

• The impact on state and local resources.

EPA has reached this conclusion based on consideration of all of the information gathered during the rulemaking process.

EPA has already stated that any option that is finalized must ensure that all federally funded and approved transportation projects in PM

2.5

areas are consistent with Clean Air Act section 176(c)(1)(B). As stated in the December 2004 proposal, to meet this provision under Option 2, we would need to conclude that it was necessary to wait until the SIP is developed to understand the potential air quality impacts of projects in any PM

2.5

area. EPA is unable to support such a conclusion based on our current scientific understanding of transportation-related PM

2.5

hot-spots, as described in C. of this section. Delaying the application of a PM

2.5

hot-spot requirement until SIPs are submitted would not ensure that new projects of air quality concern do not cause or contribute to any new PM

2.5

violations, worsen any existing violations, or delay timely attainment prior to SIP submission.

EPA originally proposed Option B in November 2003 because the potential for transportation-related PM

2.5

hot-spots was not clearly understood at that time. Rather than not establish any PM

2.5

hot-spot requirement due to the scientific uncertainty regarding PM

2.5

hot-spots, EPA proposed an alternate option to allow states to identify project locations of concern through the SIP development process, when information for potential PM

2.5

hot-spots was available. After considering other scientific information, EPA revisited Option B in its December 2004 supplemental proposal, and provided new options to more broadly evaluate

the potential for PM

2.5

hot-spots from transportation sources.

EPA also presented a possible legal argument in the November 2003 and December 2004 proposals that Option B may be consistent with the purpose of conformity to ensure that federally funded or approved transportation projects are consistent with the SIP in a given nonattainment or maintenance area. Section 176(c)(1)(A) requires “conformity to an implementation plan's purpose of eliminating or reducing the severity and number of violations of the national ambient air quality standards and achieving expeditious attainment of such standards * * *.” However, EPA has now determined that Clean Air Act section 176(c)(1)(B) requiring that projects not create or worsen NAAQS violations is the applicable legal standard for this final rule. This legal standard could only be met if PM

2.5

SIPs would be developed that identify all potential project locations of air quality concern for any such project proposed in the transportation plan or TIP for years to come.

In the December 2004 supplemental proposal, EPA further considered the feasibility of implementing Option B, as to whether sufficient information existed to allow a state to specify all susceptible locations where PM

2.5

hot-spots are an air quality concern. We acknowledged that there may be cases where it is unclear whether susceptible locations for hot-spots exist, or where there is a potential for localized PM

2.5

violations but it is difficult to specify which project locations could create hot-spots. EPA also requested comment on how the proposed options should be implemented in cases where the latest information available on the potential for PM

2.5

hot-spots is not reflected in the PM

2.5

SIP.

EPA concludes there are other reasons to believe that Option B does not meet Clean Air Act conformity requirements. SIPs are generally developed to meet regional air quality concerns that are more in parallel with the regional emissions analysis for plan and TIP conformity determinations. As such, EPA does not anticipate requiring PM

2.5

SIP modeling to be performed at a level of detail that would identify all potential transportation hot-spots. There are also concerns regarding the ability of the SIP to evaluate the local air quality impacts of all future projects, even those that are not even identified during and after the SIP's development. And finally, it is unclear how EPA would enforce a conformity requirement like Option B if SIPs do not identify hot-spot concerns when appropriate.

Based on all of these considerations and the comments received, EPA does not believe that it is realistic or practical to expect that Option B which bases hot-spot analysis requirements solely on the SIP can be sufficiently implemented to meet statutory requirements in all PM

2.5

areas.

Comment

A few commenters also argued that EPA may not lawfully finalize options that defer PM

2.5

hot-spot analyses until after a SIP is submitted because such delays are inconsistent with Clean Air Act requirements. The commenters cited several legal arguments. First, commenters believed that where a SIP of any kind exists, Clean Air Act section 176(c)(1) does not require that a state must first have adopted a SIP for a given standard before the conformity requirements for that standard apply.

These commenters also argued that the statute requires conformity to apply as soon as the one-year conformity grace period expires for areas that have Clean Air Act section 110 SIPs in effect. Unless, EPA finds that an area lacks a section 110 SIP (which is not the case for any area), they believed that conformity determinations that meet all statutory requirements are required for projects in areas that have previously been designated nonattainment for PM

2.5

, even if they were not previously PM

nonattainment or maintenance areas.

Furthermore, the commenters stated that the one-year conformity grace period does not even apply to PM

2.5

nonattainment areas that have been previously designated nonattainment for the PM

air quality standards. These commenters believed that the grace period does not apply if an area is designated nonattainment for a new or revised standard for the same criteria pollutant, in this case, the standards for PM

2.5

are for the same pollutant as for PM

(i.e., particulates). The commenter cited EPA's 1997 rulemaking that promulgated the PM

2.5

standards, in which EPA rejected arguments that PM

2.5

was a new pollutant that required listing under Clean Air Act section 108 prior to adopting a new standard. The commenter also referred to the DC Circuit decision that held that PM

2.5

has always been regulated as a fraction of PM

and that EPA was not required to list PM

2.5

as a new pollutant.

American Trucking Assns

U.S. EPA, 175 F.3d 1027, 1055 (DC Cir. 1999).

Response

As explained above, EPA agrees that it is not appropriate to defer project level hot-spot analyses until SIPs are developed, and thus has not chosen these proposed options in the final rule. EPA also agrees that all conformity requirements apply one year after an area is newly designated nonattainment with respect to a given NAAQS if the state has a general section 110 SIP. To that end, conformity will apply in PM

2.5

nonattainment areas as of April 5, 2006, since all areas of the country do have section 110 SIPs. PM

nonattainment areas continue to be subject to conformity requirements applicable to the PM

standards, which are covered by this final rule and our existing conformity regulations.

However, EPA disagrees with the commenter's assertion that the one-year conformity grace period for newly designated nonattainment areas does not apply for PM

2.5

nonattainment areas that are also PM

nonattainment or maintenance areas. The grace period is clearly applicable by its own terms to an area for one year after it is first designated nonattainment for a specific standard. The grace period would apply for all new standards, even if they are different standards for the same pollutant. Section 176(c)(6) states, “Notwithstanding paragraph 5, this subsection shall not apply with respect to an area designated nonattainment under section 107(d)(1) until 1 year after that area is

first designated nonattainment for a specific national ambient air quality standard.

This paragraph only applies with respect to the national ambient air quality standard for which an area is newly designated nonattainment and

does not affect the area's requirements with respect to all other national ambient air quality standards for which the area is designated nonattainment

or has been redesignated from nonattainment to attainment with a maintenance plan pursuant to section 175A (

including any pre-existing national ambient air quality standard for a pollutant for which a new or revised standard has been issued

).” (Emphasis added). The statute thus expressly differentiates between new and existing standards for a given pollutant, and specifically provides the grace period for new standards that may apply for the same pollutant. EPA does not believe there is any ambiguity in the applicability of the grace period under the statute. EPA acknowledges that PM

2.5

and PM

are both standards applicable to particulate matter, but concludes that given the express language of the statutory grace period there is no question that it applies to newly designated PM

2.5

nonattainment areas. In addition, the grace period for PM

2.5

will terminate in April 2006, so

any concerns about this issue will become moot at that point.

Comment

EPA also requested comment on how Option B should be implemented in cases where the latest information available on the potential of PM

2.5

hot-spots is not reflected in the SIP (December 13, 2004; 69 FR 72148). Such cases would result if information becomes available outside the SIP process that indicates that there may be potential transportation-related hot-spot locations. Some commenters were concerned that it may not be possible to identify all types of projects or locations that could be an air quality concern in the time addressed by the SIP or in future years. New projects of air quality concern that are not addressed by a SIP, the commenter argued, should require a PM

2.5

hot-spot analyses to protect public health.

Response

EPA considered the concerns raised by commenters. In developing the final rule, EPA considered the ability of all PM

2.5

SIPs to identify every project of air quality concern in the timeframe of the SIP and future years, and how such projects at locations not identified in the SIP could meet Clean Air Act conformity requirements without a PM

2.5

hot-spot analysis. EPA did not finalize Option B in the final rule, since the Agency concluded that it is unreasonable to believe that all projects of air quality concern would be identified by the SIP and therefore required to comply with the conformity provisions of the Clean Air Act.

Comment

Some commenters were concerned that the final rule use state and local resources effectively. These commenters, however, differed in their reasons for supporting various options. First, some commenters were concerned that finalizing requirements that required PM

2.5

hot-spot analyses for all projects (Options 3 and C) could result in an inefficient use of state and local resources that could be used for SIP development, and additional monitoring of the potential and location for PM

2.5

hot-spots. A few commenters acknowledged that many agencies are also addressing conformity for the 8-hour ozone standard, which takes away resources for PM

2.5

. Other commenters stated that agencies will not have PM

2.5

data, such as monitoring data and inventory estimates, until SIPs are developed or maybe not at all. These commenters stated that the majority of PM

2.5

monitors have been in place for less than five years and many do not collect speciated data, which they believed is critical to pinpointing likely sources of PM

2.5

. Other commenters supported not requiring any PM

2.5

hot-spot analyses (Options 1 and A) or delaying the final rule altogether, which would allow state and local agencies to focus resources on other planning and SIP efforts.

Other commenters believed that a more effective use of resources would be to identify PM

2.5

problem locations during the SIP development process (through Options 2 and B), which would allow state and local agencies to determine if and where hot-spot analyses would apply. The SIP process allows states and regions to acquire necessary data and research which allows for more conclusive information. All of these commenters believed that focusing PM

2.5

hot-spot requirements on PM

2.5

air quality problem areas and potential sources that matter would better use limited state and local resources.

However, other commenters believed that the options involving no hot-spot analyses or tying hot-spot analyses to SIPs (Options 1, 2, A, and B) would not protect public health since these options would eliminate or narrow any requirement to perform PM

2.5

hot-spot analyses. Furthermore, some commenters believed that options that were consistent with the existing PM

hot-spot requirements (Options 3 and C) would be easier to implement for areas with previous CO or PM

hot-spot analysis experience. Two commenters further stated that these options would be more consistent with how their state is already considering PM

2.5

localized impacts under state environmental requirements.

Response

EPA believes that the final rule will ensure that state and local resources are used in an efficient manner, since hot-spot analyses will only be required for projects of air quality concern. Eliminating qualitative analyses for projects that are not an air quality concern based on EPA's conclusion that such projects will not create or worsen air quality violations will significantly reduce any challenges in implementing this final rule, since the majority of projects that are usually proposed are not projects of air quality concern. Therefore, most project-level conformity determinations will not contain a hot-spot analysis of any kind, since most projects are not in danger of impacting the PM

2.5

standards.

As noted above, EPA concludes that requirements keyed only to SIP development may not assure conformity of all projects and thus believes it cannot address the resource issue through such options. However, EPA believes that requiring analyses only for projects of air quality concern will both ensure that all projects meet the statutory requirements and provide sufficient resources to conduct all necessary analyses.

EPA agrees that there are start-up issues that some state and local agencies will need to overcome, especially areas without previous experience in implementing a hot-spot requirement in CO or PM

areas. However, EPA and DOT's qualitative hot-spot guidance, and our future quantitative hot-spot modeling guidance for projects of air quality concern will assist in the implementation of this final rule. As always, EPA will continue to, in cooperation with DOT, work to assist state and local agencies in implementing the final rule's requirements.

Finally, EPA would like to address the comment that further PM

2.5

monitoring data needs to be gathered before applying a hot-spot requirement. EPA disagrees with this comment. There is sufficient evidence that projects of air quality concern can affect local PM

2.5

concentrations, and therefore, waiting for additional monitoring data used in SIP development for every PM

2.5

area is not necessary to meet statutory conformity requirements now. Also, EPA believes that PM

2.5

hot-spot analyses can be completed for projects of air quality concern even if PM

2.5

monitoring data is not available for a given project's location. EPA will clarify in its future quantitative hot-spot modeling guidance how monitoring data of current and past PM

2.5

air quality can be used in estimating future PM

2.5

air quality concentrations.

Comment

Other commenters were concerned that EPA has not yet issued PM

2.5

quantitative hot-spot analysis guidance and methods. Some commenters supported doing little or no hot-spot analyses, in part because they asserted that credible tools are not currently available and quantitative analyses would not be required until guidance were available, possibly just before the April 5, 2008 PM

2.5

SIP deadline. However, other commenters believed that all of the proposed options were insufficient since they would delay quantitative PM

2.5

hot-spot analyses for years, and in the interim, there would be no consideration of the public health impacts of projects currently under development.

Finally, some commenters believed that EPA needed to issue qualitative PM

2.5

hot-spot guidance, since the existing PM

qualitative hot-spot guidance was not applicable to PM

2.5

hot-spot analyses. These commenters noted that PM

2.5

is chemically different than PM

and most of the PM

2.5

areas are violating the annual PM

2.5

standard, whereas most PM

areas were constrained by the 24-hour PM

standard.

Response

Today's final rule extends § 93.123(b)(4) of the existing conformity rule's PM

hot-spot provisions to PM

2.5

areas. This provision now requires that quantitative PM

2.5

hot-spot analyses be performed once EPA announces in the

Federal Register

that quantitative analysis requirements are in effect. EPA has not yet made such an announcement because the Agency has not approved appropriate motor vehicle emissions factor models for localized analyses, and EPA is in the initial stages of developing quantitative PM

2.5

and PM

modeling guidance to apply existing air quality dispersion models and future emissions factor models to implement today's rule. Please see Section VI. of today's final rule for further information on the timing of quantitative hot-spot requirements.

EPA agrees that the existing PM

qualitative hot-spot guidance is not applicable to PM

2.5

analyses. As a result, EPA and DOT have developed qualitative PM

2.5

hot-spot guidance for immediate use for conformity determinations for projects of air quality concern, which is available at the Web site listed in Section I.B.2. of today's action.

Comment

Some commenters believed that EPA could improve on its proposed options in the final rule. Some examples of commenters' suggestions are as follows:

• Clarifying or expanding the list of projects for which quantitative analyses are to be conducted;

• Adopting a screening method or emissions threshold that would help define what projects require quantitative hot-spot analyses; and,

• Allowing both the MPO and state or local air agency to have the opportunity to identify further projects that should undergo quantitative review.

The screening procedure is necessary, one commenter believed, to avoid unnecessary effort associated with PM

2.5

hot-spot analyses and project-level conformity determinations. Still another commenter believed that any hot-spot requirement should be limited in geographic scope to those parts of the nonattainment area where monitors indicate that PM

2.5

levels are above a standard or forecasts indicate they are projected to reach such levels.

Response

EPA has responded to similar comments in other sections of today's action. The final rule addresses many of the suggestions submitted by commenters by further defining what projects need hot-spot analyses to meet statutory requirements and conserve resources. See Section V. for further information on the regulatory criteria for quantitative hot-spot analyses. The elimination of qualitative hot-spot analyses for many projects in part addresses the motivation for a screening method or emissions threshold—i.e., to focus more rigorous quantitative analyses on projects of air quality concern.

EPA also agrees that the air quality circumstances can be considered in further narrowing the focus of quantitative hot-spot analyses. See Section VII. of this notice for further discussion on how such information could be considered for future categorical hot-spot findings.

Comment

EPA also proposed Option 4 and 5 for the time period before PM

2.5

SIPs are submitted. Two commenters preferred Option 4 which allowed for a finding that hot-spots were not of air quality concern to any other pre-SIP option. One of these commenters preferred Option 4 because it offered the best combination of conformity review continuity and flexibility in determining which projects required PM

2.5

hot-spot analyses. The commenter argued that its state needed to have PM

2.5

hot-spot analyses prior to PM

2.5

SIP submission because many transportation projects would be developed during this time period that could negatively impact air quality. Allowing for a “grace period” before project impacts are considered prior to SIP submission could increase hot-spot emissions, the commenter argued. All of these commenters, however, agreed that Option 4 was consistent with past practice for applying PM10 hot-spot requirements and meeting statutory requirements while providing some relief when EPA and the state air agency has information that PM

2.5

hot-spots are not a concern in a given area. On the other hand, other commenters did not support Option 4 for the same reasons that they did not support Option 3, which are described in a previous summary.

Some commenters supported Option 5 because they believed that this option reflected the current state of scientific understanding, used resources efficiently, addressed the learning curve for areas without PM experience, and relied on future development of PM

2.5

SIPs. Option 5, commenters argued, is appropriate because it provided an opportunity for each PM

2.5

area to tailor its hot-spot requirements when information exists prior to PM

2.5

SIP submission. However, other commenters stated specific opposition to Option 5; these commenters saw this option as a “loophole” for not protecting PM

2.5

air quality, since it would presume that PM

2.5

hot-spot analyses were not needed unless a finding was made. These commenters expressed doubt that such findings would be done at all in any PM

2.5

area.

EPA also requested comment on whether state and local air agencies will have the necessary data and other information to make the findings described for Options 4 and 5. Comments were mixed on this point. For example, three commenters who supported Option 5 believed that there would not be sufficient information regarding PM

2.5

hot-spot potential prior to the development of a PM

2.5

SIP in a given area. Other commenters who supported either Option 3 or 4 believed that there would be information to support making findings based on either existing air quality monitoring data, current state screening thresholds, or other techniques for what projects need PM

2.5

hot-spot analyses.

Response

EPA originally proposed Options 4 and 5 because of what was seen at the time as the evolving nature of our understanding of PM

2.5

air quality issues. These options would rely on the proposed interpretation stated in the November 2003 proposal (68 FR 62713): Clean Air Act section 176(c)(1)(B) requirements could be met as long as explicit reviews are performed at locations identified in the PM

2.5

SIP as susceptible to PM

2.5

hot-spots. Both Options 4 and 5 were intended to allow EPA and states to target hot-spot requirements in PM

2.5

nonattainment areas where hot-spots may or may not be an air quality concern.

However, EPA is not finalizing these options either because they do not meet statutory requirements as explained above, or the final rule already provides the flexibility intended by the originally proposed options. In addition, EPA was not convinced based on the comments received that either option was feasible

in identifying all projects of air quality concern.

Comment

There were a few commenters who believed that PM

2.5

hot-spot analyses would not be an efficient use of resources because of their individual PM

2.5

nonattainment area's circumstances. Several commenters stated that it is inefficient to direct resources to PM

2.5

hot-spot analyses when transportation may not be a significant contributor to the PM

2.5

air quality problem in a given area, such as smaller areas or cities dominated by other PM sources (

e.g.

, wood smoke from residential stoves, fireplaces or other forms of residential heating). Another commenter pointed out that the only exceedance of the 24-hour PM

2.5

standard in his area was attributable to a fireworks display. This same commenter believed that transportation projects would not impact the annual PM

2.5

standard, which the commenter stated was more relevant in most areas, or jeopardize the 24-hour standard.

Another commenter believed that his state needed flexibility to consider through the SIP process and consultation the hot-spot concerns of its remote communities. Another commenter stated that hot-spot analyses for projects in non-urbanized areas are never justified because such projects lack the size and density to allow other modes to effectively serve travel needs. A failed conformity test in these areas would simply leave real highway problems unresolved, the commenter hypothesized.

One commenter stated that local agencies, including the MPO, have little or no ability to implement or require control measures or make project design changes that could impact PM

2.5

at the project level. Also, the commenter believed transportation agencies have no control over existing Federal diesel fuel and off-road standards.

Response

EPA believes that today's final rule protects air quality and public health in PM

2.5

areas and provide an option for areas where on-road motor vehicles are an insignificant regional and local contributor to an area's particulate matter problem. Today's final rule targets PM

2.5

hot-spot analyses on the types of projects that are likely to cause or contribute to new or worsened PM

2.5

violations. Specifically, the rule targets hot-spot analyses on those types of projects that result in significant increases in diesel vehicle traffic (and therefore emissions), which is likely to be a small subset of transportation projects in most areas. In addition, the final rule's minor addition to 40 CFR 93.109(k) will allow PM

2.5

areas with insignificant regional emissions to also demonstrate, when appropriate, that individual transportation projects will not create new localized violations or make existing violations worse.

For example, isolated rural PM

2.5

areas where other types of sources such as wood stoves or fireplaces are dominant at the regional level would only be required to perform hot-spot analyses for the types of projects described in § 93.123(b) until such time as a PM

2.5

SIP is submitted which demonstrates that regional on-road motor vehicle PM

2.5

emissions are insignificant and will not cause new or worsen existing local violations. EPA also notes that the impact of the final rule may be minimal in such smaller areas, since areas that are dominated by other sources do not typically have complex transportation systems needing new project approvals prior to PM

2.5

SIP submission.

April 2003, T

ransportation/Air Quality Issues in Rural Areas,

FHWA and Dye Management Group; and October 2003,

Rural Conformity: A Survey of Practice,

NCHRP Project 08-36, Task 28, prepared by ICF Consulting and Sarah J. Siwek and Associates.

After EPA makes an adequacy finding (or approves) a SIP that demonstrates insignificant regional and local emissions, PM

2.5

hot-spot analyses, would no longer be required in that area. EPA discussed its process for evaluating SIPs that claim insignificant regional and localized emissions in the June 30, 2003 proposal (68 FR 38984) and July 1, 2004 final rule (69 FR 40061-40063). EPA Regions and states can work together to appropriately expedite the processing of such SIPs through such methods as parallel processing or direct final rulemaking.

With regard to the concerns expressed about the appropriateness of hot-spot analyses in remote or non-urbanized areas, EPA would like to point out that today's final rule limits the need for PM

2.5

hot-spot analyses to only those projects which significantly increase diesel vehicle traffic and emissions. As noted above, this is likely to be only a small percentage of projects in remote or non-urbanized areas.

With regard to the comment concerning the ability of MPOs to influence the design of individual projects and the ability of transportation agencies to have control over Federal diesel fuel standards and non-road equipment emissions standards, EPA would like to point out that in most cases hot-spot analyses are completed by project sponsors during the project's environmental review phase. Project sponsors are often state departments of transportation which do have the ability to modify project designs or take other steps to mitigate emissions from the individual project. While it is true that state and local transportation agencies cannot influence national diesel fuel standards, the state and local agencies can be assured that EPA is implementing these standards as planned and that the diesel sulfur standard and heavy duty engine rule will be phased in beginning in 2007.

With regard to the comment on national non-road emissions standards, the commenter is correct that state and local transportation agencies do not have control over such standards. EPA notes that non-road emissions are considered to the extent that they are expected to impact background concentrations in PM

2.5

hot-spot analyses of on-road highway and transit projects of air quality concern. EPA's future modeling guidance will address how background concentrations are to be calculated for quantitative hot-spot analyses.

Comment

A few commenters argued that EPA's standards for low sulfur diesel fuels in 2006 and heavy-duty engines in 2007 will negate any need for PM

2.5

hot-spot analyses. The commenters stated that EPA should analyze the impacts of these Federal standards on local air quality before PM

2.5

hot-spot analysis requirements are finalized.

Response

In the December 2004 supplemental proposal (69 FR 72147), EPA committed to consider the impact of the new diesel fuel and engine standards (January 18, 2001, 66 FR 5002) in the development of the final rule. Such standards are expected to significantly impact the amount of particulate emissions that will be emitted by new diesel vehicles, and consequently may impact the potential for PM

2.5

transportation-related hot-spots. EPA considered the time frame over which these vehicle standards would phase in. According to the latest Vehicle Inventory and Use Survey from the Census Bureau

, in 2002, vehicles three years of age and younger constituted only 32.3% of U.S. truck fleet. If the same age distribution holds for 2010, only about one third of trucks on the road will meet the heavy-duty engine emissions standards for 2007 and 2010. In this scenario, most trucks on the road will still be capable

of producing elevated concentrations of PM

2.5

. As such, EPA's new emission standards do not eliminate the need for considering PM

2.5

hot-spots from transportation projects involving a significant number of diesel vehicles. However, consideration of EPA's diesel fuel and engine standards' impact on background air quality will be addressed as part of EPA's future quantitative modeling guidance and possibly in modeling used to support categorical hot-spot findings as described in Section VII. of today's notice.

This information can be found at:

http://www.census.gov/svsd/www/vius/products.html.

Comment

One commenter mentioned that EPA has never required hot-spot analyses prior to SIP development for any other pollutants. The commenter stated that significant CO and PM

conformity requirements were not effective until after inventory and air quality models were developed and tested, and SIPs were submitted. Agencies could build on SIP submissions and technical analyses to perform hot-spot analyses. For PM

2.5

, the commenter was concerned that planning agencies will not have this technical information nor the necessary modeling tools and experience.

Response

EPA disagrees with this comment. Hot-spot analyses have in the past been required in areas before SIPs were developed. In fact, Clean Air Act section 176(c)(3)(B)(ii) requires that before CO SIPs were developed, projects could only be found to conform if they eliminated violations or reduced the number or severity of violations. As a result, hot-spot modeling was required to determine whether or not violations were being eliminated or the severity or number of violations were being reduced.

As part of today's rulemaking, EPA believes that scientific evidence supports the conclusion that certain types of projects, particularly those involving significant increases in diesel vehicle traffic and emissions, could cause new violations or worsen existing violations. Therefore, EPA could not finalize a regulation that solely relied on the SIP process to identify locations or types of projects that could cause new violations or worsen existing ones with no hot-spot analyses being required before the submission of a SIP or no analyses being required if the SIP did not address this issue. The final rule does allow for the SIP to identify additional projects or project locations of concern; however, in the face of available scientific evidence concerning projects which could adversely effect localized air quality, EPA is required to establish hot-spot analysis requirements for the types of projects identified in § 93.123(b)(1).

As discussed in this preamble, initially areas will be required to carry out qualitative analyses until such time as EPA announces in the

Federal Register

that quantitative analysis requirements are in effect. The quantitative requirements will not be put into effect until after EPA releases appropriate modeling guidance and the MOVES motor vehicle emission factor model is released, as described further in Section V. of today's action. EPA and DOT have developed guidance on how to complete qualitative hot-spot analyses during the period before quantitative analyses requirements are put into effect. This guidance will be posted on the website provided in Section I.B.2. of today's notice. Therefore, conformity implementers will have the tools and information necessary in order to carry out hot-spot analyses.

Comment

Some commenters also noted that EPA acknowledged in its proposals that the science surrounding the new PM

2.5

standards is ongoing. These commenters cited preamble language from the November 2003 proposal that air quality data indicates that PM

2.5

is a regional pollutant like ozone, and therefore PM

2.5

hot-spot analyses should not be required until there is scientific evidence of localized concerns, especially in areas where exceedances are dominated by sources emitting secondary rather than direct PM

2.5

emissions.

Response

EPA disagrees with this comment. As noted in C. of this section, EPA believes that directly emitted PM

2.5

from transportation sources can be both a regional and local air quality concern. Based on an evaluation of more recent studies, EPA has concluded that certain types of projects could be of local air quality concern and therefore has finalized the rule to require hot-spot analyses for all such projects at all times.

Comment

One commenter believed that future changes to the current PM

2.5

air quality standards should be considered, especially if EPA selects any option involving identifying hot-spot concerns through the SIP. The commenter believed that future SIPs should be completed with respect to more protective PM

2.5

standards. This commenter argued that more stringent PM

2.5

standards could significantly increase the potential for transportation projects to cause or contribute to PM

2.5

violations.

Other commenters noted that existing PM

2.5

standards were in process of being revised, or that the public health benefits of controlling hot-spots indicate that EPA consider more health-protective standards.

Response

EPA did not finalize hot-spot analysis requirements that rely solely on an area's SIP to identify the types of projects or project locations that require a hot-spot analysis. However, EPA does not believe it is appropriate to address the remainder of these comments concerning the pending review of the current PM

2.5

standards at this time.

The commenters are correct that EPA is in the process of reviewing the current PM

2.5

air quality standards. As required by consent decree, EPA proposed revisions to the current PM

2.5

air quality standards on January 17, 2006 (71 FR 2620). EPA is required to finalize this rulemaking by September 27, 2006. When reviewing an air quality standard, EPA considers available health effects data. As such EPA is considering any available health information related to localized elevated PM

2.5

concentrations.

EPA will consider the need to revise the conformity rule if appropriate after any changes to the PM

2.5

standards are finalized. However, today's final rule protects air quality and public health in current PM

2.5

nonattainment areas according to the current standards. This is accomplished by ensuring that projects that are likely to cause new or worsen existing violations with respect to the currently applicable standards undergo a hot-spot analysis before a project-level conformity determination is made.

Comment

EPA invited commenters to submit studies or data regarding PM

2.5

hot-spots during the comment period for the December 2004 supplemental proposal. Comments varied regarding whether or not transportation projects could impact the level and forms of the current PM

2.5

standards at the local level.

Response

EPA reviewed the information submitted by these commenters along with a large number of other studies as discussed above. Based on a review of all of the data, EPA concluded that certain types of individual transportation projects, particularly

those which significantly increase diesel vehicle traffic and emissions, could lead to new violations or could worsen existing violations of either the current annual or 24-hour form of the PM

2.5

standards. Particularly relevant are the Indale and Burr studies cited in C. of this section. The Indale study showed that facilities where diesel vehicles idle for prolonged periods, such as truck stops or freight terminals, can cause elevated PM

2.5

concentrations in the vicinity of the facility.

The Burr study showed that individual highway projects can also result in significant changes in PM

2.5

. Specifically, in the Burr study, a highway bypass opened which removed traffic from a roadway that runs through the affected town. After the bypass opened, PM

2.5

concentrations decreased in the town near the roadway where traffic was removed, thereby documenting the impact that traffic had been having on local air quality. Based on this and other information in the docket for the final rule, EPA concluded that certain projects could cause air quality concerns, and therefore, a hot-spot analysis is required for these projects.

E. Responses to Other Comments

EPA received several comments regarding other issues related to its statutory interpretations supporting proposed options. Please note that some of these comments were related to both PM

2.5

and PM

hot-spot requirements, and for the sake of completeness, EPA is including the entire comment and response in Section III.

Comment

EPA noted in its previous proposals that Clean Air Act section 176(c)(3)(B)(ii) only specifically requires hot-spot analyses for projects in CO nonattainment areas, and therefore, EPA has discretion to decide if hot-spot analyses are necessary to protect air quality in PM

2.5

and PM

nonattainment and maintenance areas. EPA received comments concerning this interpretation of the Agency's statutory authority during the comment period following the November 2003 proposal and invited further comments in the December 2004 supplemental proposal.

EPA received several comments on this particular legal argument. Four commenters believed that EPA demonstrated in the December 2004 supplemental proposal that all proposed options complied with Clean Air Act requirements and that EPA has discretion in applying PM hot-spot requirements. These commenters argued that the Clean Air Act does not specifically require PM

2.5

or PM

hot-spot requirements for any projects. One of these commenters further clarified that EPA has the discretion to specify the form of analyses, based on availability of information, feasibility of analysis methods, and cost and benefit of performing analyses.

However, other commenters disagreed with this interpretation, and believed that the Clean Air Act does not provide EPA the discretion to exempt federally funded or approved projects from project-level conformity determinations, including PM

2.5

and PM

hot-spot analyses. Rather than being superceded by section 176(c)(3)(B)(ii) which establishes a special requirement to reduce CO violations, applicable only to CO areas before a SIP is approved, these commenters believed that Clean Air Act section 176(c)(1)(A) and (B) take precedence. Section 176(c)(1)(A) and (B) apply for all pollutants for which an area is designated nonattainment pursuant to Clean Air Act section 107(d), and “Conformity to an implementation plan” means that the activity must satisfy these statutory requirements “that such activities will not cause or contribute to any new violation of any standard in any area,” “increase the frequency or severity of any existing violation of any standard in any area” or “delay timely attainment.” Since EPA does not have discretion to waive these statutory requirements, these commenters believed that PM

2.5

and PM

hot-spot analyses should be required, consistent with the statute, for “any activity” before it may be approved or funded by a Federal agency.

Response

EPA agrees that the Clean Air Act sets the legal standard for what projects have to meet before receiving Federal funding or approval (i.e., that they cannot create or worsen violations of any standard or delay attainment). EPA also agrees that Clean Air Act 176(c)(1)(A) and (B) set this standard, rather than 176(c)(3)(B)(ii). However, EPA also believes it has discretion to not require analyses of localized impacts of projects if we have scientific evidence that PM

2.5

and PM

hot-spots are not a concern with respect to the standards. That is, even under the statutory standards of section 176(c)(1)(A) and (B), if EPA determines through rulemaking that certain types of projects will not cause or contribute to violations of any standard or delay attainment, EPA concludes that we have the authority to determine through the conformity rule that no additional analysis would be necessary to meet section 176(c)(1)(A) and (B). Since section 176(c)(3)(B)(ii) does not affirmatively require emissions reductions in PM

2.5

or PM

areas, EPA believes that conformity determinations would satisfy section 176(c)(1)(A) and (B) without a hot-spot analysis if EPA has demonstrated that specific types of projects will not adversely affect air quality standards. EPA certainly did not mean to imply in its proposals that we could arbitrarily disregard consideration of PM

2.5

and PM

localized emissions impacts even if such impacts could impact the air quality standards.

EPA agrees that we do not have authority to waive the requirements of Clean Air Act section 176(c)(1)(A) and (B), rather we conclude that those requirements can be met in certain circumstances without additional hot-spot analyses. Nevertheless, since we have information that PM

2.5

and PM

hot-spots are a concern for certain projects, we are interpreting the statute to apply a specific hot-spot requirement to those projects of air quality concern.

Comment

Other commenters believed that EPA should revise § 93.116(a) of the conformity rule so that proposed transportation projects can meet all Clean Air Act conformity requirements. These commenters argued that EPA had not reflected in the proposed regulatory text all of the requirements of Clean Air Act section 176(c)(1)(A) and (B)(i)(iii) that transportation activities must contribute to reducing violations and providing for expeditious attainment. According to commenters, the Clean Air Act establishes an affirmative responsibility on transportation projects to help attain the standards, and as a result, the conformity rule should be clarified to prohibit conformity determinations for projects that cause or contribute to new or increased violations after a statutory attainment deadline, or that fail to eliminate transportation-related violations by an attainment date.

The commenters provided an example to illustrate their comments. In this example, a CO hot-spot analysis determined that the number of current CO violations would be eliminated by 2015, but that continued growth in vehicle miles traveled (VMT) thereafter would cause at least one new violation by 2020. The concentration for the violating receptor represented a decrease in the concentration predicted at the same receptor under the no-build scenario. In the commenters' opinion, the fact that the violation would be less than current violations, or less than would be expected under the no-build scenario, is not enough to meet statutory

requirements after an area has attained, or after the attainment date.

Response

EPA disagrees with commenters and believes that § 93.116(a) of the conformity rule meets all statutory requirements. Section 176(c)(1)(A) requires “conformity to an implementation plan's purpose of eliminating or reducing the severity and number of violations of the national ambient air quality standards and achieving expeditious attainment of such standards.” In general, EPA believes that this statutory criterion is met if a transportation project is consistent with the emissions projections and control measures in the SIP.

The SIP process is the venue where state and local agencies decide on SIP control strategies for attaining the PM

2.5

and PM

standards. Section 93.116(a) of the conformity rule allows all projects in PM

2.5

and PM

areas to meet section 176(c)(1)(A) because it requires all non-exempt projects to demonstrate that “no new local violations will be created and the severity or number of existing violations will not be increased as a result of the project.” This is accomplished by requiring PM

2.5

and PM

hot-spot analyses for projects of air quality concern, with the presumption that all other projects meet this requirement.

EPA has previously addressed a similar type of comment regarding the applicability of section 176(c)(1)(A) and commenters' belief that this provision requires transportation activities to specifically contribute emissions reductions towards attainment. Although it is true that transportation projects need to be consistent with a SIP's purpose of reducing violations, this can be accomplished by simply not increasing violations; EPA concludes that the statute does not require an individual transportation project to reduce emissions by itself. Individual transportation projects are not required to reduce all transportation-related emissions; they need only prevent worsening air quality concentrations. So long as the air quality standards are not impacted by a new project, the project will meet all applicable statutory requirements by not causing or contributing to new violations, not increasing the severity of existing violations, not interfering with timely attainment and interim progress, and being consistent with the overall purpose of the SIP to eliminate all violations.

In the July 1, 2004 final rule, EPA disagreed with this similar comment (69 FR 40031). Clean Air Act section 176(c)(3)(A)(iii) is the only provision that requires emissions reductions for transportation plans and TIPs in higher classifications of ozone and CO nonattainment areas prior to having an adequate or approved SIP. This provision does not apply in the case of PM

2.5

and PM

nonattainment and maintenance areas. EPA has already successfully defended this legal interpretation in

EDF

EPA, 82 F.3d 451 (DC Cir. 1996).

Furthermore, commenters are incorrect in interpreting section 176(c)(1)(B)(i) and (iii) as prohibiting project approvals in cases where new violations are predicted for a year beyond an attainment year and a project's implementation is resulting in lower PM

2.5

and PM

concentrations. The commenters indicated that in this context, “any new violation” should be construed to apply to a violation that is anticipated in the period after the area attains the standards.

Sections 176(c)(1)(A) and (B) should not be interpreted that “any new violation” should be construed to imply that an individual transportation project must remedy any violation that is projected to occur after the attainment date as a result of any emissions sources. On the contrary, these provisions only require air quality to not be worsened by an individual project than what would have otherwise occurred. Where the project itself is improving air quality concentrations and thus violations from what they would have been without the project, EPA concludes that the project is consistent with the SIP and meets the applicable conformity requirements.

As a result, EPA believes that conformity in the example offered by the commenter meets statutory requirements. If the project's implementation resulted in lower future concentrations than would have otherwise occurred without the project, then statutory conformity requirements are met. In fact, such a situation would result in more than what is required under the statute, since such a project has actually reduced future violations from what they would have been absent the project.

Comment

Two commenters believed that transportation plans and TIPs cannot be found to conform if they include projects that do not meet Clean Air Act requirements. The commenters stated that the conformity rule does not explain how MPOs will implement the Clean Air Act requirement to not “approv[e] any project, program or plan which does not conform.” The commenters believed that if projects are found not to conform after the TIP has been approved, there should be a requirement to reconsider the TIP so that there is an opportunity to revisit the regional allocation of available resources. If this opportunity is not provided, commenters were concerned that resources may not be available to remedy or mitigate the impacts of a particular project's conformity determination.

Response

EPA believes that MPOs and project sponsors are already fulfilling the Clean Air Act requirement to not “approv[e] any project, program or plan which does not conform.” Furthermore, existing transportation planning and conformity requirements already provide the opportunity to reconsider the allocation of resources in the event that a project cannot meet project-level conformity requirements.

Section 93.122(a)(1) of the conformity rule requires that regional emissions analyses, which serve as the basis for determining whether or not an area conforms to an approved or adequate SIP motor vehicle emissions budget or passes an interim emissions test before budgets are available, include all regionally significant projects expected in the nonattainment or maintenance area and account for the VMT from non-regionally significant projects that are not explicitly modeled. Clearly, not all of the expected projects planned for an area would have received a project-level conformity determination prior to the time that they are included in the regional emissions analysis for a nonattainment or maintenance area because project-level determinations are not made until a project completes the required National Environmental Policy Act (NEPA) process.

If during the NEPA process a project initially does not meet project-level hot-spot requirements, there would be two possible outcomes. In most cases the project sponsor would attempt to mitigate project emissions that are affecting concentrations either through changes in the project's design or through implementation of other measures that reduce concentrations within the geographic area impacted by the project. If a project sponsor was not able to mitigate the impacts of such project, the project could not move forward because a project-level conformity determination could not be made. Since transportation plans and TIPs are updated on a regular basis, the MPO would be able to reallocate the

funding from the project to other projects at that time.

Comment

One commenter recommended that EPA not finalize any PM

2.5

or PM

hot-spot requirements because doing so would be contrary to what Congress originally intended. This commenter argued that Congress enacted the 1990 Clean Air Act Amendments to focus on the emissions impacts of long-range transportation plans and TIPs. The commenter stated that the key conformity test is whether emissions from the long-range transportation plan or TIP, in their entirety, stay within the SIP's motor vehicle emissions budget, and the impact of any single project on plan/TIP area-wide emissions could be minimal. Meeting the SIP's budget and attaining the air quality standards on a county and regional level, the commenter argued, is the primary mechanism for an area reaching attainment, rather than a momentary increase in the standards at a specific project's location. The commenter believed that projects can be found to conform without PM hot-spot analyses as long as such projects are part of a conforming plan and TIP. The risk of possible legal challenges and delays in streamlining project development would not be a productive use of resources, the commenter also argued.

Response

EPA disagrees with these comments. Clean Air Act section 176(c)(2) does require that in order for a project to be found to conform it must come from a conforming plan and TIP and/or its emissions must have been included in the current conformity determination. However, this is not the sole statutory requirement that must be satisfied in order for a project-level conformity determination to be made. Transportation projects must also satisfy the requirements of section 176(c)(1)(B). Section 176(c)(1) is written very broadly to apply to any Federal activity, and specifically applies to any project as well as any transportation plan or TIP.

Specifically, projects can only be found to conform if it can be shown that they do not cause or contribute to new violations, increase the frequency or severity of existing violations, or delay timely attainment of the relevant air quality standard. EPA has determined that certain types of transportation projects may result in localized PM

2.5

violations. Therefore, in order to satisfy the requirements of Clean Air Act section 176(c)(1)(B), a hot-spot analysis is required for such projects in order to ensure that new violations are not created, existing violations are not worsened, and timely attainment is not delayed. A regional emissions analysis for an area's entire planned transportation system is not sufficient to ensure that individual projects meet the requirements of section 176(c)(1)(B) where projects could have a localized air quality impact.

EPA agrees that regional emissions analyses are critical for ensuring that emissions from an area's planned transportation system are consistent with emissions estimates contained in the area's SIP, so that the area may meet relevant regional air quality goals such as attainment or reasonable further progress. However, based on a complete reading of Clean Air Act section 176(c), it is clear that Congress intended transportation conformity to apply to transportation projects as well as plans and TIPs. Thus, hot-spot analyses are required as well where localized impacts could occur.

Finally, the commenter states that the risk of possible legal challenges and delays in streamlining project development would not be a productive use of resources. But EPA cannot ignore Clean Air Act conformity requirements simply because there is a risk that some projects may be delayed due to potential lawsuits. Clean Air Act section 176(c)(1)(B) clearly requires that it must be shown that individual projects do not adversely impact air quality. In this final rule, EPA addresses both the Clean Air Act's requirements for project-level conformity determinations and concerns over limited resources. To that end, the final rule requires hot-spot analyses for only those projects that have the likelihood of adversely impacting air quality rather than requiring an analysis for each non-exempt project, including those that EPA concludes would not represent an air quality concern.

Comment

A few commenters urged EPA to consider information that they had previously submitted on the costs of performing conformity analyses for the new standards in response to EPA's proposed November 25, 2003, Information Collection Request (ICR) and final January 5, 2004, ICR (69 FR 336).

Response

EPA believes that conformity procedures must first meet the Clean Air Act requirements contained in section 176(c) and that these procedures should be sensitive to the resource constraints of conformity implementers. EPA recognizes that both air quality agencies and metropolitan planning organizations are currently involved in 8-hour ozone and/or PM

2.5

SIP development, implementation of conformity requirements for these two air quality standards and MPOs are currently adapting to changes made by SAFETEA-LU to transportation planning and conformity requirements. The final requirements for PM

2.5

hot-spot analyses meet Clean Air Act conformity requirements and minimize the resource burden on state and local agencies by focusing these reviews on only those projects that are likely to adversely impact air quality rather than requiring analyses for every non-exempt project in PM

2.5

nonattainment and maintenance areas.

In addition, EPA has already considered the additional burden associated with implementing a PM

2.5

hot-spot requirement in the ICR that has been approved for implementing transportation conformity for the 8-hour ozone and PM

2.5

standards. EPA has already considered and responded to all comments that were made for this ICR, which has been approved and assigned OMB control number 2060-0561. In fact, this ICR actually overestimated the burden associated with implementing a PM

2.5

hot-spot requirement as compared to this final rule's requirements. For example, the ICR assumed that a PM

2.5

hot-spot analysis would be required for all non-exempt federally funded or approved projects in PM

2.5

nonattainment or maintenance areas, whereas this final rule only requires such analyses for projects of air quality concern.

F. When Are the PM

2.5

Hot-Spot Requirements Effective?

Clean Air Act section 176(c)(6) and 40 CFR 93.102(d) provide a one-year grace period before conformity applies in areas newly designated nonattainment for a new standard. On January 5, 2005 (70 FR 943), EPA designated areas as attainment and nonattainment for the PM

2.5

standards. These designations became effective on April 5, 2005. As a result, conformity for the PM

2.5

standards will apply to newly designated PM

2.5

nonattainment areas on April 5, 2006. Starting on that date, PM

2.5

hot-spot requirements for projects of air quality concern as detailed by this rulemaking must be met prior to any new Federal approvals for such projects.

Therefore, EPA finds good cause to determine that the final rule is effective on April 5, 2006. EPA normally issues final regulations with at least a 30-day effective date after

Federal Register

publication. However, state and local implementers are required by the Clean Air Act to meet conformity

requirements in PM

2.5

nonattainment areas for transportation plans, TIPs, and non-exempt projects as of April 5, 2006, the end of the PM

2.5

grace period. And since today's final rule describes how to meet statutory requirements for projects in PM

2.5

areas, it is imperative that conformity implementers be able to legally use the requirements in this final rule. Absent this determination of good cause, EPA would be placing conformity implementers in the unfortunate position of waiting until a 30-day effective date before conformity rule requirements could be used to proceed with any short-term project approvals. For these reasons, EPA believes it has good cause to expedite the effective date of this final rule in PM

2.5

nonattainment areas.

IV. PM

Hot-Spot Analyses

A. Background and Proposed Options

EPA proposed to revisit existing PM

hot-spot requirements in parallel with considering new PM

2.5

hot-spot requirements. As discussed in Section III., EPA originally established a PM

hot-spot requirement in the November 24, 1993 conformity rule, which required some type of hot-spot analysis—quantitative or qualitative—for all FHWA and FTA funded or approved non-exempt projects in PM

nonattainment and maintenance areas (40 CFR 93.116 and 93.123). These requirements applied for all project-level conformity determinations that occurred before and after a PM

SIP is submitted.

EPA established the PM

hot-spot requirements so that more rigorous quantitative hot-spot analyses would only be required for projects that have the potential to impact the PM

air quality standards (i.e., “projects of air quality concern”), once modeling guidance was released. More streamlined, qualitative hot-spot analyses were required for all other non-exempt projects, and for all non-exempt projects until EPA's modeling guidance was released. All hot-spot analyses were intended to demonstrate that a transportation project meets Clean Air Act conformity requirements.

EPA proposed several options to retain, revise, or delete existing PM

hot-spot analysis requirements for project-level conformity determinations in PM

nonattainment and maintenance areas. These options were proposed to apply during the time periods before and after a PM

SIP is submitted. EPA is repeating the previously proposed options to assist in discussing the final rule in today's action.

To that end, the following options were proposed for PM

hot-spot requirements prior to the submission of a PM

SIP:

•

Option 1:

Retain the existing conformity rule's PM

hot-spot analysis requirements in all PM

areas;

•

Option 2:

Apply the existing conformity rule's PM

hot-spot analysis requirements, unless the EPA Regional Administrator or state air agency finds that localized PM

violations are not a concern for a given PM

area;

•

Option 3:

Only apply the existing conformity rule's PM

hot-spot analysis requirements, if the EPA Regional Administrator or state air agency finds that localized PM

violations are a concern for a given PM

area; or

•

Option 4:

Delete the current PM

hot-spot analysis requirements from the conformity rule and impose no hot-spot analysis requirements.

EPA acknowledged in the December 2004 supplemental proposal that the above proposed options may impact only a small number of PM

areas, since most PM

areas already have submitted or approved PM

SIPs. EPA also requested information from commenters about whether sufficient local information was available to make findings under Options 2 and 3.

EPA proposed three PM

hot-spot options for project-level conformity determinations that occur after PM

SIP submission:

•

Option A:

Retain the existing conformity rule's PM

hot-spot analysis requirements for FHWA/FTA non-exempt projects in all PM

areas with one minor addition, as described below;

•

Option B:

Only require quantitative PM

hot-spot analyses for projects at those types of locations that the PM

SIP for a given area identifies as a localized PM

air quality concern. No quantitative or qualitative analyses would be required for projects in other types of locations, or in PM

areas where the SIP does not identify types of locations as a localized PM

air quality concern; or

•

Option C:

Do not apply any PM

hot-spot analysis requirements for any PM

area and delete the current PM

requirements from the conformity rule.

Under Option A, EPA proposed to add a new criterion that would require that quantitative analyses also be performed at those types of project locations that the PM

SIP identifies as a PM

hot-spot concern. Neither Option B nor C would require some type of hot-spot analysis for all projects in the PM

nonattainment or maintenance area, as had been required under the previous conformity rule's PM

hot-spot requirements. In addition, EPA noted in the December 2004 supplemental proposal that the majority of PM

areas already had an attainment demonstration or a maintenance plan in place; therefore, SIP revisions may be necessary under Option B to identify types of locations where quantitative analyses must be performed.

For all relevant options, EPA proposed to rely on the existing conformity rule provision in § 93.123(b)(4) that does not require any quantitative PM

hot-spot analyses until EPA releases quantitative modeling guidance and announces in the

Federal Register

that quantitative modeling requirements are in effect. EPA also proposed to retain the existing conformity rule's flexibility in § 93.123(b)(3) for FTA to make categorical hot-spot findings to streamline PM

hot-spot analyses as appropriate.

EPA requested comments on all of the proposed options, and invited commenters to submit any relevant data or other information, including whether state and local agencies would have information available to implement the proposed options. The December 2004 supplemental proposal included proposed regulatory text that combined various PM

2.5

and PM

hot-spot options as illustrative examples, and EPA noted that any combination of the proposed PM

2.5

or PM

hot-spot options could be finalized. See the November 2003 proposal (68 FR 62713-62714) and December 2004 supplemental proposal (69 FR 72149-72153) for more information on the proposed options.

B. Description of Final Rule

Consistent with PM

2.5

hot-spot requirements, EPA is finalizing a hybrid approach that retains aspects of the previous PM

hot-spot requirements while providing flexibility. The final rule requires quantitative PM

SIP as a localized concern.

Today's final rule does not require any hot-spot analysis—qualitative or quantitative—for all other projects that are not listed in § 93.123(b)(1) as an air quality concern. These projects are presumed to meet Clean Air Act requirements and 40 CFR 93.116

without any explicit hot-spot analysis, because EPA concludes based upon the available evidence that such projects would not have an impact on local air quality. State and local project sponsors should briefly document in their conformity documentation for such projects that an explicit PM

hot-spot analysis was not completed because Clean Air Act and 40 CFR 93.116 requirements were met without an explicit PM

hot-spot analysis.

This final rule requires PM

hot-spot analyses for projects of air quality concern in PM

nonattainment and maintenance areas at all times—both before and after a PM

SIP is submitted. These projects are anticipated to have the potential to increase local PM

concentrations, and as a result, PM

hot-spot analyses are needed to ensure that the local air quality impacts of such projects are considered prior to receiving federal funding or approval. Rather than finalize the proposed and previous rule's criteria for PM

analyses, EPA is finalizing more specific criteria about the types of projects that require such analyses based on our November 2003 and December 2004 proposals and comments received. See Section V. of this notice for further details regarding the regulatory criteria for projects of air quality concern and more information on the general requirements for performing hot-spot analyses. See Section IX. of today's action for further information regarding when today's change in PM

requirements would apply in PM

areas with and without approved conformity SIPs.

In addition, the final rule does not substantively change the existing conformity rule flexibility that allows DOT, in consultation with EPA, to make categorical hot-spot findings that would further streamline quantitative hot-spot analysis requirements in appropriate cases, as described further in Section VII.

This final rule also makes no change in how qualitative PM

hot-spot analyses are currently performed for projects of air quality concern, since the previous conformity rule has always required a qualitative PM

hot-spot analysis for all non-exempt projects in PM

nonattainment and maintenance areas (under the previous rule's § 93.123(b)(2)). As stated in Section III., quantitative PM

hot-spot analyses are not required for projects of air quality concern at this time since EPA has not yet required quantitative PM

hot-spot analyses under § 93.123(b)(4). Qualitative PM

hot-spot analyses should be completed according to joint EPA and DOT guidance, which will be posted on the Web site provided in Section I.B.2. of today's notice. Until this new guidance is available, FHWA's existing September 12, 2001 guidance, “Guidance for Qualitative Project-Level ‘Hot-Spot’ Analysis in PM

Nonattainment and Maintenance Areas,” can be used. See Section VI. of this final rule for more information regarding the timing of EPA's future quantitative hot-spot modeling guidance and application of quantitative requirements.

Finally, EPA notes that its future quantitative modeling guidance will address how the current 24-hour and annual PM

air quality standards are to be considered in quantitative hot-spot analyses. This future guidance will be consistent with how potential impacts on the PM

standards have historically been considered for SIP planning, monitoring, and other applicable requirements.

C. Rationale

EPA considered the following factors in developing the final rule's PM

hot-spot requirements:

• The Clean Air Act conformity requirements for individual transportation projects in PM

areas;

• The current scientific understanding of PM

hot-spots and public health effects;

• The feasibility of implementing proposed options; and

• The impact of proposed options on state and local resources.

EPA stated in its proposals that it was important to re-evaluate the need for hot-spot analyses for PM

nonattainment and maintenance areas, in conjunction with similar options considered for PM

2.5

hot-spot requirements. The following paragraphs outline how EPA considered the above factors in the final rule.

When the conformity rule was promulgated in 1993, EPA interpreted Clean Air Act section 176(c)(1)(B) to require PM

hot-spot analyses because of the requirement to ensure that transportation activities do not create new violations, worsen existing violations or delay timely attainment of the air quality standard (January 11, 1993, 58 FR 3776-3777). EPA continues to believe that this statutory provision is the applicable standard that applies for considering a final PM

hot-spot requirement, and that the final rule meets this legal standard.

Furthermore, the Clean Air Act requires that section 176(c)(1)(B) be met for all FHWA or FTA funded or approved projects, except for traffic signal synchronization projects; it does not distinguish that these requirements apply based on whether or not a SIP has been submitted. Through previous rulemaking, EPA has determined that the exempt projects listed in 40 CFR 93.126 have met section 176(c)(1)(B) without further hot-spot analyses. Through today's action, EPA is determining that projects not identified in the rule as projects of air quality concern have also met section 176(c)(1)(B) without further hot-spot analyses. The final rule requires that all projects of air quality concern be analyzed for localized impacts, regardless of whether or not the PM

SIP is submitted.

As indicated in Section III. of today's notice and above, EPA believes that Clean Air Act section 176(c)(1)(B) is the primary legal standard that applies for this final rule. This statutory provision requires that federally funded and approved projects not create or worsen air quality violations or delay timely attainment. Also, since projects of air quality concern have the potential to impact local PM

air quality, then a PM

hot-spot requirement is warranted for such projects in today's final rule at all times.

EPA also continues to believe it has discretion to establish the level of PM

hot-spot analysis that is necessary to meet statutory requirements. Therefore, EPA is retaining its previous rule's approach for requiring quantitative PM

hot-spot analyses only for projects of air quality concern once EPA's modeling guidance is available. EPA is revising some of the existing rule's criteria for when PM

analyses are required based on scientific information currently available on PM

hot-spots, and the Agency's experience in implementing CO and PM

hot-spot requirements since 1993 for what level of analysis is appropriate and worthwhile. The final rule's criteria for what projects require hot-spot analyses will ensure that all projects that have the potential to impact the air quality standards will be analyzed before they receive Federal funding or approval. EPA revised its proposed and previous rule's criteria for what projects of air quality concern require PM

analyses based on existing scientific information and comments received, as discussed further in this section and in Section V.

Furthermore, as stated in Section III., EPA is changing its precedent to date in no longer requiring qualitative hot-spot analyses for projects that are not of localized air quality concern. As stated previously, since the original 1993 conformity rule, some type of hot-spot analysis has been required to meet statutory requirements for all non-exempt FHWA and FTA projects in

nonattainment and maintenance areas. However, based on the history of implementation of this provision to date, EPA now believes that these projects do not represent a localized air quality concern and can be presumed to meet Clean Air Act requirements and 40 CFR 93.116 without any explicit hot-spot analysis because EPA concludes based on available data and experience that these projects will not have an impact on local air quality.

The Agency now believes that requiring qualitative hot-spot analyses for projects that are not a concern is also not a beneficial use of Federal, state, or local resources. This conclusion is based in part on a recent review by EPA and DOT field offices of project-level conformity determinations involving historical qualitative hot-spot analyses in PM

areas. See Section III.C. for further information on EPA and DOT's review of PM

qualitative hot-spot analyses and why EPA concludes that they are no longer necessary to meet statutory requirements for projects that are

not

an air quality concern.

However, EPA continues to believe that projects of air quality concern have the potential to impact PM

air quality standards and thus require explicit hot-spot analyses to determine if any such impacts will result in specific cases, based on existing scientific information and the Agency's historical understanding of PM

hot-spots. As stated in the December 2004 supplemental proposal, EPA continues to believe it is appropriate to focus conformity resources where air quality issues are significant and thus need to be in place to address Clean Air Act requirements.

In developing this final rule, EPA considered information that was available when the original 1993 conformity rule was developed, as well as new information that was submitted through the rulemaking process or has otherwise become available. For example, in 1993, EPA stated that direct PM

emissions would be capable of causing violations in conditions of unusually heavy diesel truck/bus traffic and limited dispersion, such as street canyons (January 11, 1993, 58 FR 3780). EPA has also acknowledged that the role of re-entrained road dust could be a major factor in contributing to potential PM

hot-spots, especially in PM

areas where road dust is a major component of the PM

motor vehicle emissions inventory.

EPA also considered in the final rule the impact of our new diesel fuel and engine standards (January 18, 2001, 66 FR 5002) for the necessity of applying any PM

hot-spot requirement. Such standards are expected to significantly impact the amount of particulate emissions that will be emitted by new diesel vehicles, and consequently may impact the potential for PM

transportation-related hot-spots. We considered the time frame over which these vehicle standards would phase in. According to the latest Vehicle Inventory and Use Survey from the Census Bureau, in 2002, vehicles three years of age and younger constituted only 32.3% of U.S. truck fleet. If the same age distribution holds for 2010, only about one third of trucks on the road will meet the heavy-duty engine emissions standards for 2007 and 2010. In this scenario, most trucks on the road will still be capable of producing elevated concentrations. As such, EPA's new emission standards do not eliminate the need for considering PM

As described further below, EPA also considered the feasibility and resource implications of implementing the proposed options and the final rule's requirements to meet statutory requirements before and after PM

SIP submission.

D. Response to Comments

EPA received comments from state and local transportation and air quality agencies, environmental groups, transportation advocates, and the general public with respect to the proposed options for PM

areas. Fewer comments were submitted for PM

options as compared to PM

2.5

options, and preferences were not as consistent for similar options before and after PM

SIPs are submitted, as compared to preferences for PM

2.5

options.

Comment

Several commenters supported finalizing PM

requirements that were generally consistent with the previous conformity rule's provisions for PM

areas (

i.e.

, Options 1 and A) because they believed these options were most protective of public health. Commenters also supported these options because they would promote consistency with EPA's past legal interpretations regarding how federally funded and approved transportation projects have historically met Clean Air Act section 176(c)(1)(B) requirements in PM

areas. These commenters believed that existing science and experience have shown that transportation projects can impact local PM

air quality, and therefore, previous PM

hot-spot requirements should be retained to meet statutory requirements.

These commenters generally did not support Options 4 and C since they required no PM

hot-spot analyses, and they believed that these options were inconsistent with current scientific evidence regarding the existence of PM

hot-spots. A few commenters indicated that these options also do not provide the same health protections as other options. Similarly, another commenter stated that it was not in the public's best interest to eliminate all analyses of potential PM

hot-spots, especially due to the commenter's experience with respect to the 24-hour PM

standard. Another commenter argued that hot-spot requirements should not be deleted because of the known relationship between PM

nonattainment areas and transportation-related sources.

Some of these commenters acknowledged that in practice, proposed options prior to a PM

SIP's submission would not impact most areas, but believed if any projects are approved for areas that have yet to submit a PM

SIP, those projects can only meet statutory conformity requirements through a PM

hot-spot analysis. One commenter believed that PM

areas that still do not have SIPs need to complete PM

hot-spot analyses because these SIPs are not reliable in protecting the public health of their citizens. Another commenter argued that consistency with existing PM

hot-spot requirements and procedures for conformity provides better support during environmental reviews from a NEPA and/or state environmental process perspective when determining local or project-level impacts.

Still other commenters supported options that would apply no PM

hot-spot requirements (

i.e.

, Options 4 and C), and some even preferred that EPA delay issuing a final rule until certain issues are addressed. Some of these commenters believed that there was insufficient evidence regarding the existence of PM

hot-spots. Some commenters also argued that PM

hot-spot requirements are not required by the Clean Air Act, and therefore, an option that required PM

hot-spot analyses should never be finalized.

These commenters were also opposed to requiring existing PM

hot-spot requirements (under Options 1 and A) because they believed these options

would require extensive analyses without comparable environmental benefits and flexibility. These commenters believed it was unnecessary to require hot-spot analyses for every project in every PM

area.

One of these commenters stated that they had never identified a transportation project that had a negative impact on PM

concentrations. This commenter noted that transportation projects usually reduce PM

emissions because most projects involve paving unpaved roads and/or shoulders or adding curbs or gutters. The commenter noted that in most mountainous western states, transportation-related PM

problems result from highway maintenance combined with winter air inversions rather than highway improvement projects. This commenter stated that these problems are addressed in the SIP through requirements for street sweeping, flushing and use of chemical de-icers, all of which reduce road dust. Finally the commenter indicated that eliminating PM

hot-spot requirements is preferable because state and local agencies can then focus their limited resources on other transportation and air quality efforts.

Response

As described above, EPA believes that today's final rule is the appropriate way for projects of air quality concern to meet Clean Air Act section 176(c)(1)(B) requirements in all PM

nonattainment and maintenance areas. EPA agrees that applying a hot-spot requirement prior to a PM

SIP being submitted is essential for meeting statutory requirements. EPA agrees that today's final rule is consistent with its past legal interpretations for applying hot-spot requirements for all projects of air quality concern.

EPA disagrees with commenters who argued that there is insufficient information or limited value in applying a PM

hot-spot requirement. Although some commenters noted limited value in performing qualitative PM

hot-spot analyses to date, EPA believes that this information further supports its decision to eliminate qualitative PM

hot-spot analyses for projects that are not an air quality concern, rather than eliminate all PM

hot-spot requirements.

Based on our review of scientific studies and information gathered during the rulemaking process, as described above, EPA believes that projects of air quality concern have the potential to impact PM

concentrations, and as a result, the PM

standards. Such impacts on communities surrounding a project would be contrary to the Clean Air Act's conformity requirements. Thus, EPA concludes that hot-spot analyses are necessary for projects of air quality concern. Furthermore, EPA does not agree that it is appropriate to delay finalizing a change to the PM

hot-spot requirements, for the reasons cited above. EPA has addressed state and local resource concerns by eliminating PM

qualitative hot-spot analyses for projects that are not an air quality concern.

Comment

EPA also proposed Option B that relied solely on the SIP to identify projects or project locations of potential PM

hot-spot concern. Under this option, quantitative PM

hot-spot analyses would only be required at types of project locations identified as a localized air quality concern in a given PM

SIP. No quantitative or qualitative analyses would be required for projects in other types of locations, or in PM

areas where the current or future SIP does not identify types of locations as a localized PM

air quality concern. Furthermore, no hot-spot analyses would be completed for any projects prior to PM

SIP submission, for the limited number of PM

areas without SIPs.

Several commenters supported Option B because they believed that the SIP process could assist in identifying what projects are of concern in a given area and what level of PM

hot-spot analysis is appropriate. Commenters believed that Option B would allow each PM

area to target potential PM

hot-spots, protect public health, and provide necessary flexibility. A few other commenters indicated support for Option B because they did not agree that there was evidence that transportation projects are a PM

hot-spot concern. Two other commenters even believed that this option should apply only once a SIP is approved, rather than when a SIP is submitted, unless EPA were establishing a process similar to its adequacy process for submitted SIPs with motor vehicle emissions budgets that involves sufficient notice and public review.

Other commenters opposed Option B because they believed it was not feasible, and therefore, would not meet statutory requirements or protect public health. Commenters noted that most PM

areas already have SIPs that were developed before EPA's proposed options, without consideration for implementing a conformity hot-spot requirement. If finalized, the commenters believed that Option B would result in new projects in most PM

areas not meeting statutory requirements, since no hot-spot requirement would exist (because no current PM

SIPs were designed to implement such a requirement).

Some commenters believed that Option B is also flawed because a state has no obligation under the Clean Air Act or conformity regulations to identify project locations of air quality concern in its SIP. Commenters argued that if states decline to designate such areas in their SIPs—whether from the lack of meaningful evidence of problems or out of a desire to avoid the application of conformity requirements—statutory requirements would not be met. If such a case occurred, this commenter was concerned that there would be no legal mechanism to challenge a SIP or enforce statutory conformity requirements.

A commenter who did not support Option B as proposed suggested a hybrid option where PM

areas could rely on Option B if the SIP addressed the potential for transportation-related hot-spots, but if this was not the case, the existing PM

requirements under Option A would apply.

Some commenters also provided information and thoughts on developing PM

SIPs to implement Option B. One commenter believed that revising existing SIPs to address transportation-related PM

hot-spots would allow state and local agencies to focus their resources on meaningful analyses. Some commenters believed that available local information and resources to develop SIPs to specify project locations of concern will vary among PM

areas. Still another commenter was concerned that Option B could be problematic if project locations are not identified during SIP development, but are subsequently determined through the consultation process to have a hot-spot concern. Other commenters believed that the consultation process could be used to identify new projects of concern, rather than revise existing SIPs.

Finally, a few commenters went on to state that EPA's proposed options that allow states to determine which projects would require hot-spot analyses conflict with a previous court decision. However, the commenters did not elaborate on what court decision was involved, or how Option B contradicted this judicial decision.

Response

EPA is not finalizing Option B because this option will not ensure that all federally funded and approved transportation projects in PM

areas are consistent with Clean Air Act section 176(c)(1)(B). As described by

commenters, most PM

areas already have SIPs that were established prior to EPA's proposed conformity options, and therefore, were not designed to implement Option B. Due to limited resources, it is doubtful that areas will revise SIPs solely to address PM

hot-spots, and even so, it is unclear whether SIPs could be developed with sufficient detail to consider the local impacts of current and future projects. Based on all of these considerations and the comments received, EPA does not believe that it is realistic or practical to expect that Option B can be sufficiently implemented to meet statutory requirements in all PM

areas. Further discussion on a similar option for PM

2.5

hot-spot analyses can be found in Section III. of today's action.

Comment

A few commenters supported Options 2 or 3 which would apply existing PM

hot-spot requirements depending on whether or not new or worsened local PM

violations could occur in a given area prior to PM

SIP submission. For example, one commenter believed Option 3—which would require PM

hot-spot analyses if EPA or the state air agency found there to be a hot-spot concern in a given area—would provide the ability to require analyses for certain projects. This commenter highlighted his area's experience that two types of projects listed in 40 CFR 93.126 (i.e., weight inspection stations and bus terminals) may be a PM

hot-spot concern due to a high concentration of diesel vehicles.

Response

EPA is not finalizing approaches such as Options 2 or 3 because it is unclear if they can be implemented in a manner that meets statutory requirements. See Section III. of today's action for further rationale regarding why such options are not being finalized. However, today's final rule provides some of the flexibility intended by these options, i.e., targeting PM

hot-spot analyses for projects that have the potential to impact PM

air quality.

Comment

A few commenters argued that EPA may not lawfully finalize options that defer PM

hot-spot analyses until after a SIP is submitted because such delays are inconsistent with Clean Air Act requirements. Commenters believed that Clean Air Act section 176(c)(1) does not require that a SIP for a given standard be established before conformity requirements for that standard apply. Section 176(c)(1) states that Federal and MPO approval actions cannot be done for “* * * any project * * * which does not conform to an implementation plan approved or promulgated under section 7410 of this title.”

Response

EPA agrees that it is not appropriate to defer project-level hot-spot analyses until PM

SIPs are developed, and thus has not chosen these proposed options in the final rule. See Section III. for more on EPA's response to a similar comment raised for PM

2.5

hot-spot analyses.

Comment

Some commenters were concerned that finalizing options that required PM

hot-spot analyses for all projects (Options 1 and A) could result in an inefficient use of state and local resources, and therefore, deleting or defining PM

hot-spot requirements through the SIP process was a more appropriate use of resources.

However, as stated above, other commenters believed that having no or only limited PM

hot-spot analyses did not meet statutory requirements or protect public health. Furthermore, they believed that implementing the previous PM

hot-spot requirements has not been burdensome, so continuing to do this under the final rule would be acceptable.

Response

EPA believes that the final rule will ensure that state and local resources are used in an efficient manner, since PM

hot-spot analyses will only be required for projects of air quality concern. Eliminating qualitative PM

hot-spot analyses for projects that are not an air quality concern will significantly reduce any resource challenges in implementing this final rule, since most projects should not be considered an air quality concern. As noted above, EPA concludes that this does comply with statutory requirements. EPA will continue to work with DOT to assist state and local agencies in implementing the final rule's requirements.

Comment

Other commenters were concerned that EPA has yet to issue PM

quantitative hot-spot analysis guidance and methods. Some commenters supported doing little or no PM

hot-spot analyses, in part because credible tools are not currently available. However, other commenters believed that all of the proposed options were insufficient since they would delay quantitative PM

hot-spot analyses for years, and in the interim, there would be no consideration of the public health impacts of projects currently under development.

Response

Today's final rule retains § 93.123(b)(4) of the existing conformity rule that requires quantitative PM

hot-spot analyses once EPA announces in the

Federal Register

that quantitative analysis requirements are in effect. EPA has not yet made such an announcement because the Agency believes that appropriate motor vehicle emissions factor models are not yet available for localized analyses, and EPA is in the initial stages of developing quantitative hot-spot modeling guidance to implement today's rule. Please see Section VI. of today's final rule for further information on the timing of quantitative hot-spot requirements. However, pending development of such guidance, the final rule does require qualitative PM

hot-spot analyses for all projects of air quality concern, so consideration of the public health impacts of proposed projects of air quality concern will not be delayed.

Comment

Some commenters stated that PM

hot-spot requirements should be suspended until (1) it can be demonstrated scientifically that re-entrained dust from induced traffic creates PM

hot-spots, and (2) there are more reliable techniques to quantify re-entrained PM

created by induced traffic on paved roads.

Another commenter stated that it is reasonable to expect that some projects would create localized impacts, especially due to the large amounts of re-entrained road dust generated from roadways. This commenter believed that EPA should develop criteria and guidance under which EPA, state or local air pollution control agencies would have the option of requiring project-level PM

hot-spot analyses. Another commenter went on to state that, while re-entrained road dust emissions can be a greater contributor to PM

concentrations than tailpipe emissions, most projects are done on paved roads where re-entrained road dust is less of an issue compared to unpaved roads.

Response

EPA believes based on the available evidence included in the docket for this rulemaking that certain transportation projects have the potential to impact PM

air quality standards, and therefore, a PM

hot-spot analysis for these projects is needed to meet statutory requirements. Furthermore,

sufficient scientific information exists to support the final rule's requirements, and EPA will consider whether additional information is warranted for modeling road dust in its future PM

2.5

and PM

quantitative hot-spot modeling guidance.

Comment

Some commenters believed that EPA could improve on its proposed options in the final rule, such as adopting a screening method or emissions threshold that would help define what projects require quantitative hot-spot analyses.

Response

EPA believes that today's action addresses this comment by further refining what projects are an air quality concern and need PM

hot-spot analyses. See Section V. for further information on the criteria for projects of air quality concern finalized in today's action. The elimination of qualitative hot-spot analyses for projects not of concern in part addresses the motivation for a screening method or emissions threshold—e.g., to focus more rigorous quantitative analyses on projects of air quality concern.

Comment

A few commenters argued that applying the previous PM

hot-spot requirements was not necessary due to unique circumstances of their individual PM

area. Several commenters stated that it is inefficient to direct resources to PM

hot-spot analysis when transportation projects may not be a significant contributor to the PM

problem in a given area, such as smaller areas or cities dominated by other PM sources.

One commenter said there were four PM

nonattainment and maintenance areas in their state where the operation of specific industries (e.g., quarries, cement plants, steel fabrication plants) is the primary source of direct PM

emissions. Monitors over the last ten years have shown attainment for the PM

standards, but the commenter's state had not submitted redesignation requests to maintenance for two of the areas due to local concerns for specific non-transportation sources. Therefore, this commenter supported the option of only requiring PM

hot-spot requirements if a SIP is submitted that identifies transportation sources as a significant contributor to the PM

air quality problem.

Another commenter believed its state needed flexibility to consider, through the SIP and consultation processes, the hot-spot concerns of its remote communities. The commenter believed the existing PM

hot-spot requirements resulted in a one-size-fits-all approach that is not appropriate for its PM

nonattainment and maintenance areas.

Response

EPA believes that the final rule's PM

hot-spot requirements along with the conformity rule's existing provisions concerning areas with insignificant emissions serve to protect air quality and public health in PM

nonattainment and maintenance areas. First, today's final hot-spot rule targets PM

hot-spot analyses only for projects that are likely to cause or contribute to new or worsened PM

violations. Specifically, the rule targets hot-spot analyses on those types of projects that result in significant increases in diesel vehicle traffic and emissions, which is likely to be a small subset of projects in many areas.

Second, 40 CFR 93.109(k) already allows PM

areas with insignificant regional motor vehicle emissions to demonstrate, when appropriate, that individual projects will not create new localized violations or make existing violations worse. Projects in such cases would not require PM

hot-spot analyses. Therefore, areas where other types of sources principally contribute to nonattainment problems (such

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