Clean Air Act Approval and Promulgation of PM-10 Implementation Plan for Colorado; Designation of Areas for Air Quality Planning Purposes

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[CO11-1-6532a, CO30-1-6533a, and CO36-2-6303a; FRL-5067-7]

Clean Air Act Approval and Promulgation of PM-10 Implementation

Plan for Colorado; Designation of Areas for Air Quality Planning

Purposes

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: In this document, the EPA is approving the State

implementation plan (SIP) and SIP revisions submitted by the State of

Colorado for the purpose of bringing about the attainment of the

national ambient air quality standards (NAAQS) for particulate matter

with an aerodynamic diameter less than or equal to a nominal 10

micrometers (PM-10) in Aspen, Colorado. The SIP was initially submitted

by the State on January 15, 1992, with revisions submitted on March 17,

1993 and December 9, 1993. EPA proposed to grant limited approval of

the January 1992 and March 1993 submittals in a December 23, 1993

Federal Register notice. The State's December 9, 1993 SIP revision

adequately addressed the deficiencies which had been the basis for

EPA's decision to propose limited approval of the previous submittals.

Therefore, EPA is withdrawing the limited approval and now approving

the Aspen submittals as meeting the PM-10 SIP requirements due November

15, 1991. EPA is also approving the PM-10 contingency measures for

Aspen which were included in the December 1993 submittal, and EPA is

amending the Aspen PM-10 nonattainment area boundary.

DATES: This final rule will become effective on November 14, 1994

unless adverse or critical comments are received by October 14, 1994.

If the effective date is delayed, timely notice will be published in

the Federal Register.

ADDRESSES: Comments should be addressed to Vicki Stamper, 8ART-AP, at

the EPA Region VIII Office listed. Copies of the State's submittal and

other information are available for inspection during normal business

hours at the following locations: Air Programs Branch, Environmental

Protection Agency, Region VIII, 999 18th Street, suite 500, Denver,

Colorado 80202-2405; and Air Pollution Control Division, Colorado

Department of Health, 4300 Cherry Creek Drive South, Denver, Colorado

80222-1530.

FOR FURTHER INFORMATION CONTACT: Vicki Stamper, 8ART-AP, Environmental

Protection Agency, Region VIII, 999 18th Street, suite 500, Denver,

Colorado 80202-2466, (303) 293-1765.

SUPPLEMENTARY INFORMATION:

I. Background

Aspen, Colorado was designated nonattainment for PM-10 and

classified as moderate under sections 107(d)(4)(B) and 188(a) of the

Act upon enactment of the Clean Air Act Amendments of 1990.1 (See

56 FR 56694, November 6, 1991; 40 CFR 81.306 (specifying nonattainment

designation for Aspen.)) The air quality planning requirements for

moderate PM-10 nonattainment areas are set out in subparts 1 and 4 of

part D of title I of the Act. The EPA has issued a ``General Preamble''

describing EPA's preliminary views on how EPA intends to review SIPs

and SIP revisions submitted under title I of the Act, including those

State submittals containing moderate PM-10 nonattainment area SIP

requirements (see generally 57 FR 13498 (April 16, 1992) and 57 FR

18070 (April 28, 1992)). Because EPA is describing its interpretations

here only in broad terms, the reader should refer to the General

Preamble for a more detailed discussion of the interpretations of title

I advanced in this rulemaking and the supporting rationale. In this

document on the Colorado moderate PM-10 SIP for the Aspen nonattainment

area, EPA has applied its interpretations taking into consideration the

specific factual issues presented.

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\1\The 1990 Amendments to the Clean Air Act made significant

changes to the Act. See Pub. L. No. 101-549, 104 Stat. 2399.

References herein are to the Clean Air Act, as amended (``the

Act''). The Clean Air Act is codified, as amended, in the U.S. Code

at 42 U.S.C. 7401 et. seq.

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Those states containing initial moderate PM-10 nonattainment areas

were required to submit, among other things, the following provisions

by November 15, 1991:

1. Provisions to assure that reasonably available control measures

(RACM) (including such reductions in emissions from existing sources in

the area as may be obtained through the adoption, at a minimum, of

reasonably available control technology (RACT)) shall be implemented no

later than December 10, 1993;

2. Either a demonstration (including air quality modeling) that the

plan will provide for attainment as expeditiously as practicable but no

later than December 31, 1994 or a demonstration that attainment by that

date is impracticable;

3. Quantitative milestones which are to be achieved every 3 years

and which demonstrate reasonable further progress (RFP) toward

attainment by December 31, 1994; and

4. Provisions to assure that the control requirements applicable to

major stationary sources of PM-10 also apply to major stationary

sources of PM-10 precursors except where the Administrator determines

that such sources do not contribute significantly to PM-10 levels which

exceed the NAAQS in the area. See sections 172(c), 188, and 189 of the

Act.

Some provisions were due at a later date. States with initial

moderate PM-10 nonattainment areas were required to submit a permit

program for the construction and operation of new and modified major

stationary sources of PM-10 by June 30, 1992. See section 189(a) of the

Act. Revisions to satisfy these requirements were submitted by the

State on January 14, 1993, and EPA will be taking action on these

requirements in a separate Federal Register document. Such States were

also required to submit contingency measures by November 15, 1993 which

become effective without further action by the State or EPA, upon a

determination by EPA that the area has failed to achieve RFP or to

attain the PM-10 NAAQS by the applicable statutory deadline. See

section 172(c)(9) of the Act and 57 FR 13543-13544. The State adopted

PM-10 contingency measures for Aspen in November of 1993, and those

measures were included in the State's December 9, 1993 SIP submittal.

Along with taking action on the moderate PM-10 nonattainment area SIP

requirements which were due to EPA on November 15, 1991, EPA is also

taking action on these contingency measures in this document.

II. This Action

On December 23, 1993, EPA proposed to grant limited approval of the

Aspen PM-10 SIP submitted on January 15, 1992 and revised on March 17,

1993 (see 58 FR 68094-68101). Because the State could not demonstrate

that the control measures included in the January 1992 and March 1993

SIP submittals were adequate to demonstrate timely attainment and

maintenance of the PM-10 NAAQS in Aspen, EPA was unable to propose full

approval at that time. EPA thus proposed to grant limited approval of

the submittals for the purpose of strengthening the SIP and to make the

control measures included in those submittals Federally enforceable. In

that document, EPA also proposed to fully approve those few elements of

the SIP submittals which were separable and independent of the

inadequate demonstration of attainment. EPA's proposed approval did not

include the State's voluntary no-drive day control measure, on which

EPA did not propose to take action.

The State subsequently adopted additional PM-10 control measures

for Aspen in November of 1993 and submitted the revised control

measures for approval in the SIP on December 9, 1993, along with a

revised demonstration showing that the control measures adopted and

submitted for the Aspen moderate PM-10 nonattainment area would result

in timely attainment and maintenance of the PM-10 NAAQS.

Section 110(k) of the Act sets out provisions governing EPA's

review of SIP submittals (see 57 FR 13565-13566). In this action, EPA

is withdrawing its proposal to grant limited approval published in the

December 23, 1993 Federal Register (58 FR 68094) and is, instead, fully

approving the Aspen PM-10 plan which was due to EPA on November 15,

1991 and submitted by the State on January 15, 1992, March 17, 1993,

and December 9, 1993. Note that EPA's approval does not include the

voluntary no-drive day provision submitted by the State; EPA is not

taking action on that provision at this time. Also, EPA is approving

the PM-10 contingency measures for Aspen, which were due to EPA on

November 15, 1993 and which were submitted with the additional control

measures in the State's December 9, 1993 SIP revision.

Lastly, EPA is amending the nonattainment area boundary for the

Aspen nonattainment area to include some of the area surrounding Aspen.

The revised boundary is based on information submitted with the January

1992 SIP submittal which provided a SIP equivalent demonstration

persuasively showing that the revised boundary more accurately

represents the Aspen airshed. (See section 110(k)(6) of the Act.)

Since the Aspen PM-10 SIP was not submitted by November 15, 1991 as

required, EPA made a finding, pursuant to section 179 of the Act, that

the State failed to submit the SIP and notified the Governor in a

letter dated December 16, 1991. See 57 FR 19906 (May 8, 1992). After

the Aspen PM-10 SIP was submitted on January 15, 1992, EPA found the

submittal to be complete pursuant to section 110(k)(1) of the Act and

notified the Governor accordingly in a letter dated March 16, 1992.

This completeness determination corrected the State's deficiency and,

therefore, terminated the 18-month sanctions clock under section 179 of

the Act.

A. Analysis of State Submittals

1. Procedural Background

The Act requires States to observe certain procedural requirements

in developing implementation plans and plan revisions for submission to

EPA. Section 110(a)(2) of the Act provides that each implementation

plan submitted by a State must be adopted after reasonable notice and

public hearing.2 Section 110(l) of the Act similarly provides that

each revision to an implementation plan submitted by a State under the

Act must be adopted by such State after reasonable notice and public

hearing. The EPA also must determine whether a submittal is complete

and therefore warrants further EPA review and action (see section

110(k)(1) of the Act and 57 FR 13565). The EPA's completeness criteria

for SIP submittals are set out at 40 CFR part 51, appendix V (1992).

The EPA attempts to make completeness determinations within 60 days of

receiving a submission. However, a submittal is deemed complete by

operation of law if a completeness determination is not made by EPA 6

months after receipt of the submission.

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\2\Also section 172(c)(7) of the Act requires that plan

provisions for nonattainment areas meet the applicable provisions of

section 110(a)(2).

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As discussed in the December 23, 1993 Federal Register document,

the State met the procedural requirements of the Act for the adoption

of the January 15, 1992 and March 17, 1993 SIP submittals, and EPA

found these submittals to be complete in letters dated March 16, 1992

and May 18, 1993, respectively.

After providing more than 30 days of prior public notice for the

December 1993 SIP revision, the State of Colorado held a public hearing

on November 12, 1993 to entertain public comment on the revision to the

implementation plan for Aspen. The plan for Aspen was subsequently

adopted by the State and submitted by the Governor to EPA on December

9, 1993 as a revision to the SIP. Along with the additional PM-10

controls and contingency measures for Aspen, the SIP submittal also

contained the PM-10 contingency measures for the State's other PM-10

nonattainment areas and additional PM-10 control measures for Pagosa

Springs. EPA will act on those portions of the submittal in separate

Federal Register documents.

The SIP revision was reviewed by EPA to determine completeness

shortly after its submittal, in accordance with the completeness

criteria set out at 40 CFR part 51, appendix V (1992). The submittal

was found to be complete, and a letter dated February 15, 1994 was

forwarded to the Governor indicating the completeness of the submittal

and the next steps to be taken in the review process. In this action,

EPA approves these PM-10 SIP submittals for Aspen as meeting those

moderate PM-10 nonattainment area SIP requirements due November 15,

1991 and as meeting the PM-10 contingency measure requirement due

November 15, 1993. EPA's approval does not include the voluntary no-

drive day provision which the State submitted as a PM-10 control

measure; EPA is not taking action on this control measure at this time.

Since this measure is not needed for the Aspen area to demonstrate

timely attainment or maintenance of the PM-10 NAAQS, EPA's decision not

to take action at this time on this measure does not impact the overall

approvability of the Aspen SIP submittals as meeting those moderate PM-

10 nonattainment area SIP requirements due November 15, 1991.

2. Accurate Emissions Inventory

Section 172(c)(3) of the Act requires that nonattainment plan

provisions include a comprehensive, accurate, and current inventory of

actual emissions from all sources of relevant pollutants in the

nonattainment area. Because the submission of this inventory is a

necessary adjunct to an area's attainment demonstration (or

demonstration that the area cannot practicably attain), the emissions

inventory must be received prior to or with the submission (see 57 FR

13539). An initial emissions inventory was submitted with the January

15, 1992 SIP submittal, and technical revisions to the emissions

inventory were submitted on September 20, 1993 in response to EPA

comments on the initial emissions inventory. The resulting emissions

inventory identified area sources as the primary cause of high PM-10

concentrations, with re-entrained road dust contributing 97.6 percent,

residential wood combustion contributing 2 percent, restaurant

charbroiler grills contributing 0.2 percent, and tailpipe emissions

contributing 0.2 percent. No stationary sources were identified in the

Aspen area.

In the December 23, 1993 Federal Register document, EPA proposed to

approve the emissions inventory for the Aspen, as revised on September

20, 1993 (see 58 FR 68096). This component of the State's PM-10

nonattainment area plan was considered to be separable and independent

of the deficiencies which prohibited EPA from granting full approval of

the January 1992 and March 1993 PM-10 SIP submittals. The emissions

inventory represents an assessment of PM-10 emissions in an area prior

to the adoption of control measures, and EPA did not expect the Aspen

PM-10 emissions inventory to change as a result of any additional

control measures adopted. No comments were received on EPA's December

23, 1993 proposed approval of the emissions inventory, and the

emissions inventory was not changed in the State's December 9, 1993

submittal. Therefore, EPA is finalizing its approval of the emissions

inventory. EPA believes the emissions inventory is accurate and

comprehensive and provides a sufficient basis for determining the

adequacy of the attainment demonstration for this area consistent with

the requirements of section 172(c)(3) of the Act.3 For further

information, please refer to the December 23, 1993 Federal Register

document (58 FR 68096-68097) and the Technical Support Document (TSD)

associated with this action, which is available at the EPA office

identified at the beginning of this document.

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\3\The EPA issued guidance on PM-10 emissions inventories prior

to the enactment of the Clean Air Act Amendments in the form of the

1987 PM-10 SIP Development Guideline. The guidance provided in this

document appears to be consistent with the revised Act. See section

193 of the Act.

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Under EPA's transportation conformity regulations promulgated on

November 24, 1993 (58 FR 62188-62253), a State's nonattainment area

plan should define the motor vehicle emissions budget for which Federal

transportation plans must demonstrate conformity. However, for the

Aspen PM-10 nonattainment area, the motor vehicle emissions budget was

not explicitly stated in the SIP, as the SIP was developed and

submitted prior to the promulgation of the transportation conformity

rules. To reduce future misinterpretation on this issue, EPA, with

concurrence from the State, has calculated the motor vehicle emissions

budget based on the motor vehicle emissions inventory and the

attainment demonstration presented in the SIP. Using the SIP's estimate

of motor vehicle related emissions (including tailpipe and re-entrained

road dust emissions) in the attainment year of 1994, accounting for the

effect of the motor vehicle related control measures that will be

implemented in 1994, the motor vehicle emissions budget was calculated

to be 14,312 pounds per day.

States also have the option of developing motor vehicle emissions

budgets for other years. In an August 26, 1994 letter of concurrence on

the attainment year motor vehicle emissions budget, the State

acknowledged its intent to establish an emissions budget for 1997

pursuant to its 1997 maintenance demonstration for the Aspen PM-10

nonattainment area. The 1997 motor vehicle emissions budget was thus

calculated by the State (based on the 1997 information from the SIP as

discussed above) to be 13,974 pounds per day (excluding the emissions

reductions from the voluntary no-drive day, on which EPA is not taking

action at this time). For further details, please refer to the State's

submittals and the TSD.

3. RACM (Including RACT)

As noted, the initial moderate PM-10 nonattainment areas must

submit provisions to assure that RACM (including RACT) are implemented

no later than December 10, 1993 (see sections 172(c)(1) and

189(a)(1)(C) of the Act). The General Preamble contains a detailed

discussion of EPA's interpretation of the RACM (including RACT)

requirement (see 57 FR 13539-13545 and 13560-13561).

In broad terms, the State should identify available control

measures, evaluating them for their reasonableness in light of the

feasibility of the controls and the attainment needs of the area. A

State may reject an available control measure if the measure is

technologically infeasible or the cost of the control is unreasonable.

In addition, RACM does not require controls on emissions from sources

that are insignificant (i.e., de minimis) and does not require the

implementation of all available control measures where an area

demonstrates timely attainment and the implementation of additional

controls would not expedite attainment.

Colorado's moderate PM-10 SIP revision for Aspen targeted three

source categories for emissions reductions: re-entrained road dust,

residential wood combustion, and charbroiler grill emissions.

Specifically, the State adopted transportation control measures, street

sweeping and sanding provisions, a voluntary wood burning curtailment

program, limits on installation of new wood stoves and fireplaces, and

requirements for new restaurant charbroiler grills to control PM-10

emissions. The following table represents the benefits that these

control measures are projected to resulting towards attaining the PM-10

NAAQS in Aspen:

------------------------------------------------------------------------

Benefit towards reducing

Source Control PM-10 emissions

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Re-entrained road Transit expansion, No credit taken for these

dust. 400 park-n-ride strategies.

spaces.

Crosstown shuttle Reduction of 400 vehicle

service. miles of travel (VMT)/

day.\1\

Paid parking......... No credit taken in 1994

attainment demo;

reduction of 13,070 VMT/

day expected during

maintenance years (1994-

1997).\1\

250 space intercept No credit taken in 1994

lot and shuttle. attainment demo;

reduction of 2,640 VMT/

day expected during

maintenance years (1994-

1997).\1\

Peak hrs bus priority Reduction of 1,020 VMT/

lane. day.\1\

Event strategies..... No credit taken for these

provisions.

Specs for sanding 58 percent reduction in re-

materials. entrained road dust from

minor arterial roadways.

Street sweeping...... 19 percent reduction in re-

entrained road dust

emissions from Hwy 82.

Residential wood Voluntary wood 10 percent reduction in

combustion. burning curtailment. residential wood

combustion emissions.

Limitations on new Effectiveness incorporated

wood stoves and into future year

fireplaces. emissions inventories.

Charbroiler grills... Requires PM-10 Effectiveness incorporated

controls on grills. into future year

emissions inventories.

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\1\The reductions in vehicle-miles-travelled (i.e., VMT) will ultimately

result in an emissions decrease from re-entrained road dust emissions.

Note that the credit listed in this table for the 250 space

intercept lot has been changed from the original credit requested by

the State for this control measure in its December 1993 SIP submittal

because the original credit was calculated incorrectly by the State

(the State based the credit on 300 parking spaces, rather than 250).

The pounds per day emission reduction expected from the specifications

for sanding materials was also calculated incorrectly by the State in

its December 1993 SIP submittal. The State corrected these calculations

and adjusted the attainment and maintenance demonstrations accordingly

in a June 1, 1994 submittal. See the TSD for further information.

The State did not take credit for the mass transit service

expansion and provision of 400 park-n-ride spaces because these

measures are needed to meet the increased demand in ridership expected

due to the other transportation control measures in Aspen. Also, the

State did not request any credit for the event strategies, which

consist of additional strategies to be implemented during the 10-day

period prior to and including President's Day in February of each year.

The State adopted these event strategies because the majority of PM-10

exceedances in Aspen have occurred during this timeframe due to an

influx of visitors to the Aspen area, and the State wanted to provide

extra assurance that there would be no future PM-10 exceedances during

this timeframe.

The State did not take credit for the paid parking requirements or

for the provision of the 250 space intercept lot and shuttle into Aspen

in the 1994 attainment demonstration because the State's regulation

does not require these measures to be implemented until June 1, 1994.

Thus, the State only took the credit requested for these measures in

its 1997 maintenance demonstration.

The State also requested credit for a voluntary no-drive day in its

maintenance demonstration (1994-1997), but not in the attainment

demonstration, for the Aspen nonattainment area. EPA is not taking

action on this control measure at this time. Declining to take action

at this time on this measure does not impact the approvability of the

SIP submittals as meeting RACM, since the combination of the other

control measures adopted and submitted is adequate to demonstrate

timely attainment and maintenance of the PM-10 NAAQS in the Aspen

nonattainment area.

The requirements described in the table will be implemented through

Section III of the Colorado regulation entitled ``Nonattainment Areas''

(effective 3/2/93, with revisions effective 12/30/93). Except for the

paid parking and 250 space intercept lot and shuttle measures described

above, this State regulation requires implementation of these control

measures by December 10, 1993. These control measures are expected to

result in an estimated overall reduction of 3987 lb/day of PM-10

emissions in the Aspen area by the end of 1994.

In order to comply with the State's Administrative Procedures Act,

the revisions to this regulation adopted on November 12, 1993 did not

become effective until December 30, 1993. However, the State adopted an

emergency rule on November 12, 1993 to make the new provisions in the

State's nonattainment area regulation effective December 1, 1993. Until

the State's regulation became effective, the emergency rule (which is

identical to the State nonattainment area regulation) applied beginning

December 1, 1993.

For an area that demonstrates attainment by the applicable

attainment date, the implementation of otherwise available control

measures is not ``reasonably'' required by RACM if such control

measures would not expedite attainment. (See 57 FR 13543.) Control of

other PM-10 emissions in the area, such as tailpipe emissions and coal

burning stoves, was not required because the implementation of such

controls would not have further advanced the attainment date in the

area.

Similarly, RACM (including RACT) did not require the adoption of

otherwise available control measures for stationary sources in the

Aspen nonattainment area because point source emissions in the Aspen

area are de minimis (see 57 FR 13540) and control of such sources would

not expedite attainment of the PM-10 NAAQS.

A more detailed discussion of the individual source contributions,

their associated control measures, and an explanation as to why certain

available control measures were not implemented can be found in the

TSD. The EPA has reviewed the State's explanation and associated

documentation and has concluded that it adequately justifies the

control measures to be implemented. The implementation of Aspen's PM-10

control strategy is projected to result in the attainment of the PM-10

NAAQS by December 31, 1994. Therefore, by this document, EPA is

approving Colorado's SIP submittals for the Aspen nonattainment area as

meeting the RACM including RACT requirement. However, as discussed

above, EPA is not taking any action on the voluntary no-drive day

provision at this time.

4. Demonstration

As noted, the initial moderate PM-10 nonattainment areas must

submit a demonstration (including air quality modeling) showing that

the plan will provide for attainment as expeditiously as practicable

but no later than December 31, 1994 (see section 189(a)(1)(B) of the

Act). Alternatively, the State must show that attainment by December

31, 1994 is impracticable.

EPA regulations provide that attainment be demonstrated by means of

a proportional model or dispersion model or other procedure shown to be

adequate and appropriate for such purposes. (See 40 CFR 51.112(a).) In

general, EPA policy recommends that the preferred approach for

estimating the air quality impacts of emissions of PM-10 is to use

receptor modeling in combination with dispersion modeling. On July 5,

1990, EPA issued guidance providing that, in certain situations, it may

be more appropriate to rely on a receptor modeling demonstration alone

as the basis for the attainment demonstration (see July 5, 1990 memo to

Regional Air Branch Chiefs from Robert D. Bauman, Chief of SO2/

Particulate Matter Programs Branch and Joseph Tikvart, Chief of Source

Receptor Analysis Branch). Aspen meets the criteria discussed in the

July 5, 1990 memo to justify using receptor modeling alone and,

therefore, the State utilized receptor modeling in the attainment and

maintenance demonstrations provided for the Aspen moderate PM-10

nonattainment area.

The attainment and maintenance demonstrations presented in the

December 9, 1993 submittal (as amended by the State's June 1, 1994

letter correcting errors in the original control measure credits)

indicated that the NAAQS for PM-10 in the Aspen area would be attained

in 1994 and maintained through December 31, 1997. The 24-hour PM-10

NAAQS is 150 g/m3, and the standard is attained when the

expected number of days per calendar year with a 24-hour average

concentration above 150 g/m3 is equal to or less than one

(see 40 CFR 50.6). The annual PM-10 NAAQS is 50 g/m3, and

the standard is attained when the expected annual arithmetic mean

concentration is less than or equal to 50 g/m3 (id.) The

demonstration provided by the State predicted a 24-hour design

concentration in the attainment year of 1994 of 136 g/m3.

The demonstration also predicted a 24-hour design concentration of 133

g/m3 in 1997 (excluding the credit requested for the

voluntary no-drive day on which EPA is not taking action at this time).

Thus, the State's attainment and maintenance demonstrations showed that

the control measures adopted for the Aspen area would adequately result

in attainment and maintenance of the 24-hour PM-10 NAAQS. Since the

demonstration provided by the State for Aspen clearly shows attainment

and maintenance of the 24-hour PM-10 NAAQS, it is reasonable and

adequate to assume that the protection of the 24-hour standard will be

sufficient to protect the annual standard as well. The control

strategies used to achieve these design concentrations are summarized

in Section II.A.C. of this document entitled ``RACM (including RACT).''

For a more detailed description of the attainment demonstration and the

control strategy used, see the TSD.

5. PM-10 Precursors

The control requirements which are applicable to major stationary

sources of PM-10 also apply to major stationary sources of PM-10

precursors, unless EPA determines such sources do not contribute

significantly to PM-10 levels in excess of the NAAQS (see section

189(e) of the Act).

An analysis of the State's submittal of air quality and emissions

data, as revised on September 20, 1993, for the Aspen nonattainment

area indicates that exceedances of the NAAQS are attributable chiefly

to particulate matter emissions from area sources, mainly re-entrained

road dust from paved and unpaved roads and residential wood combustion.

In addition, the emissions inventory for this area did not reveal any

major stationary sources of PM-10 precursors. In its December 23, 1993

notice of proposed rulemaking, EPA proposed to find that major

stationary sources of PM-10 precursors do not contribute significantly

to PM-10 levels in excess of the NAAQS in Aspen (see 58 FR 68098). EPA

received no comments on that finding, and the State's December 9, 1993

SIP revision did not include any information that would impact EPA's

proposed finding. Therefore, EPA is finalizing its finding that major

stationary sources of precursors of PM-10 do not contribute

significantly to PM-10 levels in excess of the NAAQS in Aspen. On

August 18, 1994, EPA partially approved the State's nonattainment new

source review (NSR) permitting regulations for the Aspen moderate PM-10

nonattainment area (among others) because the State did not submit NSR

permitting regulations for sources of PM-10 precursors in Aspen and

because EPA had not yet found that such sources did not contribute

significantly in Aspen (see 59 FR 42500). The consequence of this

finding is to exclude major stationary sources of PM-10 precursors in

Aspen from the applicability of PM-10 nonattainment area control

requirements, including nonattainment NSR permitting requirements.

Thus, the State's nonattainment NSR regulations for Aspen are

considered fully approved.

Further discussion of the analyses and supporting rationale for

EPA's finding are contained in the TSD accompanying this document. Note

that while EPA is making a general finding for this area, this finding

is based on the current character of the area including, for example,

the existing mix of sources in the area. It is possible, therefore,

that future growth could change the significance of precursors in the

area. The EPA intends to issue future guidance addressing such

potential changes in the significance of precursor emissions in an

area.

6. Quantitative Milestones and Reasonable Further Progress

The PM-10 nonattainment area plan revisions demonstrating

attainment must contain quantitative milestones which are to be

achieved every 3 years until the area is redesignated attainment and

which demonstrate RFP, as defined in section 171(1), toward attainment

by December 31, 1994 (see section 189(c) of the Act). RFP is defined in

section 171(1) of the Act as such annual incremental reductions in

emissions of the relevant air pollutant as are required by part D or

may reasonably be required by the Administrator for the purpose of

ensuring attainment of the applicable NAAQS by the applicable date.

While section 189(c) of the Act plainly provides that quantitative

milestones are to be achieved until an area is redesignated to

attainment, it is silent in indicating the starting point for counting

the first 3-year period or how many milestones must be initially

addressed. In the General Preamble, EPA addressed the statutory gap in

the starting point for counting the 3-year milestones, indicating that

it would begin from the due date for the applicable implementation plan

revision containing the control measures for the area (i.e., November

15, 1991 for initial moderate PM-10 nonattainment areas). (See 57 FR

13539.) As to the number of milestones, EPA believes that at least two

milestones must be initially addressed. Thus, submittals to address the

SIP revisions due on November 15, 1991 for the initial moderate PM-10

nonattainment areas must demonstrate that two milestones will be

achieved (first milestone: November 15, 1991 through November 15, 1994;

second milestone: November 15, 1994 through November 15, 1997). For

areas that demonstrate timely attainment of the PM-10 NAAQS, the second

milestone should, at a minimum, provide for continued maintenance of

the standards.\4\

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\4\Section 189(c) provides that quantitative milestones are to

be achieved ``until the area is redesignated attainment.'' However,

this endpoint for quantitative milestones is speculative because

redesignation of an area as attainment is contingent upon several

factors and future events.

EPA believes it is unreasonable to require planning for each

nonattainment area to cover quantitative milestones years into the

future because of the possibility that such time may elapse before

an area is in fact redesignated attainment. On the other hand, EPA

believes it is reasonable for States initially to submit a

sufficient number of milestones to ensure that there is on-going air

quality protection beyond the attainment deadline. Addressing two

milestones will ensure that the State continues to maintain the

NAAQS beyond the attainment date for at least some period during

which an area could be redesignated attainment. However, in all

instances, additional milestones must be addressed if an area is not

redesignated attainment within the time period covered by the

initial milestones submitted.

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In implementing the quantitative milestone and RFP provisions for

this initial moderate area, EPA has reviewed the attainment

demonstration and control strategy for the area to assess whether the

initial milestones have been satisfied and to determine whether annual

incremental reductions different from those provided in the SIP

submittals should be required in order to ensure attainment of the PM-

10 NAAQS by December 31, 1994 (see section 171(1) of the Act). The

State of Colorado's PM-10 SIP submittals for Aspen indicate that the

control measures adopted will result in a reduction of 3987 lb/day of

PM-10, and the State demonstrated that this annual incremental

reduction will result in attainment of the PM-10 NAAQS by December 31,

1994. This satisfies the first quantitative milestone.\5\ The State has

also demonstrated that the plan will provide for maintenance of the PM-

10 NAAQS through the end of 1997. This satisfies the second milestone

due for the area. Therefore, EPA approves the Aspen PM-10 SIP

submittals as satisfying the initial quantitative milestones and RFP

requirements.

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\5\For areas that demonstrate timely attainment of the PM-10

NAAQS, the emissions reduction progress made prior to the attainment

date of December 31, 1994 (only 46 days beyond the November 15, 1994

milestone achievement date) will satisfy the first milestone

requirement (57 FR 13539). The de minimis timing differential makes

it administratively impracticable to require separate milestone and

attainment demonstrations.

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7. Enforceability Issues

All measures and other elements in the SIP must be enforceable by

the State and EPA (see sections 172(c)(6), 110(a)(2)(A) of the Act and

57 FR 13556). The EPA criteria addressing the enforceability of SIPs

and SIP revisions were stated in a September 23, 1987 memorandum (with

attachments) from J. Craig Potter, Assistant Administrator for Air and

Radiation, et al. (see 57 FR 13541). Nonattainment area plan provisions

must also contain a program that provides for enforcement of the

control measures and other elements in the SIP (see section

110(a)(2)(C) of the Act).

The control measures contained in the SIP are addressed above under

Section II.A.3. entitled ``RACM (Including RACT).'' These control

measures, which are included in Section III. of the State Regulation

entitled ``Nonattainment Areas'' (effective 3/2/93, with revisions

effective 12/30/93), apply to the types of activities identified in

that discussion, including emissions from re-entrained road dust and

residential wood combustion. The State regulation provides that these

control measures apply throughout the Aspen PM-10 nonattainment area.

The only exemptions provided in the regulation are from the wood

burning curtailment program: EPA Phase II wood burning devices are

exempt from the wood burning curtailment program in order to encourage

conversions to cleaner wood burning devices. This is consistent with

the recommendations for voluntary wood burning curtailment programs

provided in EPA's Guidance Document for Residential Wood Combustion

Emission Control Measures.

Consistent with the attainment demonstration previously described,

the SIP submittals and State regulation require that all affected

activities for which the State is taking credit towards demonstrating

attainment must be in full compliance with the applicable SIP

provisions by December 10, 1993. In addition to the applicable control

measures, this includes the applicable recordkeeping requirements which

are addressed in the supporting information. (As discussed in Section

II.A.3., two of the control measures which pertain to parking fees and

implementation of an intercept lot and shuttle service are not required

to be implemented until June 1, 1994. Accordingly, the State did not

take credit for these measures in the 1994 attainment demonstration for

Aspen.) Compliance with certain measures, such as the 1 percent fines

limit with regard to street sanding material used, must be determined

in accordance with appropriate test methods. The regulation provides

that compliance with the 1 percent fines limit will be determined in

accordance with the American Society for Testing Materials (ASTM)

``Standard Method for Sieve Analysis of Fine and Coarse Aggregate.''

EPA believes this method is appropriate for determining compliance with

this provision.

The TSD associated with this action contains further information on

enforceability requirements including: a description of the rules

contained in the SIP and the source types subject to them, test

methods, and reporting and recordkeeping requirements. EPA has reviewed

the State's nonattainment area regulation, as revised in the State's

December 9, 1993 SIP submittal, for enforceability and has determined

that it meets all of the criteria included in the September 23, 1987

Potter Memorandum.

The State of Colorado has a program that will ensure that the

measures contained in the SIP submittals for Aspen are adequately

enforced. The Colorado Air Pollution Control Division (APCD) has the

authority to implement and enforce all emission limitations and control

measures adopted by the Colorado Air Quality Control Commission (AQCC).

In addition, Colorado statute provides that the APCD shall enforce

against any ``person'' who violates the emission control regulations of

the AQCC, the requirements of the SIP, or the requirements of any

permit. The definition of ``person'' includes, among other things, any

``municipal corporation, county, city and county or other political

subdivision of the State,'' such as the City of Aspen. Many of the

control measures adopted by the AQCC in the State nonattainment

regulation require the City of Aspen and Pitkin County to implement the

measures. This is allowed under section 110(a)(2)(E) of the Act, as

long as the State provides the necessary assurances that the State has

the responsibility for ensuring adequate implementation of the plan

provisions. Since State statute allows for the enforcement against any

county or city and since the State regulation containing the control

measures was adopted by the AQCC, the APCD has adequate authority to

ensure implementation of the control measures at the local level. State

statute provides for civil penalties of up to $15,000 per day per

violation for any person in violation of these requirements, and

criminal penalties are also provided for in the State statute. Thus,

the APCD has adequate enforcement capabilities to ensure compliance

with the Aspen PM-10 regulations. The TSD contains further information

on the State-wide regulations, enforceability requirements, and a

discussion of the personnel and funding intended to support effective

implementation of the control measures.

8. Contingency Measures

As provided in section 172(c)(9) of the Act, all moderate

nonattainment area SIPs that demonstrate attainment must include

contingency measures. See generally 57 FR 13510-13512 and 13543-13544.

These measures were required to be submitted by November 15, 1993 for

the initial moderate PM-10 nonattainment areas. Contingency measures

should consist of other available measures that are not part of the

area's core attainment control strategy. These measures must take

effect without further action by the State or EPA, upon a determination

by EPA that the area has failed to make RFP or attain the PM-10 NAAQS

by the applicable statutory deadline. The State's December 9, 1993

revision to the Aspen PM-10 SIP included the following contingency

measures: Section III.D. of the State regulation entitled

``Nonattainment Areas'' requires that (1) each user of street sanding

material in the Aspen PM-10 nonattainment area reduce the amount of

street sanding materials applied by 20 percent from the base sanding

amount; and (2) Pitkin County pave 3 bus pullouts on Highway 82 (which

is the main highway through the City) and pave the Highway 82 road

shoulder at the Owl Creek turnoff establishing a new paved lane at this

intersection. The State's regulation provides that, upon a

determination by EPA that the area failed to make RFP or attain the

NAAQS by the December 31, 1994 statutory deadline, the reduction in

sanding materials applied must be implemented within 60 days of EPA's

determination and that the paving is to be completed as soon as

possible, but no later than the end of the first complete paving season

after EPA's determination. These provisions will become legally

effective immediately upon EPA's determination that the Aspen area

failed to make RFP or attain the NAAQS by the December 31, 1994

statutory deadline. EPA believes the regulation provides adequate

timeframes for implementation.

After review of the contingency measures described above, EPA

believes they are adequate to meet the requirements of section

172(c)(9) of the Act. Therefore, EPA is approving the PM-10 contingency

measures for the Aspen PM-10 nonattainment area. For further

information, see the TSD accompanying this document.

9. Revisions to the Nonattainment Area Boundary

The Aspen nonattainment area boundary as announced on November 6,

1991 (see 56 FR 56736) is currently defined as the city limits of Aspen

in 40 CFR 81.306. However, on June 20, 1991, the State adopted a more

inclusive boundary for the Aspen PM-10 nonattainment area, which

included some of the area surrounding the City of Aspen. This revised

boundary was submitted with the Aspen PM-10 SIP in January of 1992. As

discussed in the December 23, 1993 Federal Register document, the SIP

provided a demonstration showing that the revised boundary represented

the reasonable Aspen airshed by considering the local topography,

meteorology, and land use practices (see 58 FR 68100). EPA proposed to

amend the Aspen PM-10 nonattainment area boundary in its December 23,

1993 Federal Register documet, and no comments were received on that

proposed action. Therefore, EPA is finalizing the amendments to the

Aspen PM-10 nonattainment area boundary in this document. Pursuant to

section 110(k)(6) of the Act, EPA is correcting the Aspen PM-10

nonattainment area boundary in 40 CFR 81.306 to include some of the

additional area surrounding the city of Aspen. The legal definition of

the revised Aspen nonattainment area submitted by the State is as

follows:

The area encompassed by the following Parcel ID numbers, as defined

by the Pitkin County Planning Department: 2737-29, 2737-28, 2737-21,

2737-20, 2737-19, 2737-18, 2737-17, 2737-08, 2737-07, 2737-06, 2735-22,

2735-15, 2735-14, 2735-13, 2735-12, 2735-11, 2735-10, 2735-03, 2735-02,

2735-01, 2641-31, 2643-36, 2643-35, 2643-34, 2643-27, 2643-26.

A map displaying these Parcel ID numbers can be obtained by calling

or writing the Pitkin County Planning Department at 130 South Galena

Road, Aspen, Colorado 81611; (303) 920-5090.

Final Action

EPA is approving the State of Colorado's PM-10 SIP for the Aspen

PM-10 nonattainment area, which was submitted by the State on January

15, 1992, March 17, 1993, and December 9, 1993, as meeting those

moderate PM-10 SIP requirements which were due to be submitted November

15, 1991. Among other things, the State of Colorado has adequately

demonstrated that the Aspen moderate PM-10 nonattainment area will

attain the PM-10 NAAQS by December 31, 1994. As discussed above, EPA's

approval does not include the State's voluntary no-drive day provision,

on which EPA is not taking action at this time. EPA's approval also

includes the PM-10 contingency measures for Aspen, which were included

with the State's December 9, 1993 SIP revision.

As noted, on January 14, 1993, the State submitted revisions to its

permit program for the construction and operation of new and modified

major stationary sources of PM-10 to comply with the amended Act. EPA

will be taking action on these requirements in a separate Federal

Register document.

Lastly, EPA is amending the nonattainment area boundary for the

Aspen nonattainment area to include some of the area surrounding the

City of Aspen.

The EPA is publishing this action without prior proposal because

the Agency views this as a noncontroversial action and anticipates no

adverse comments. However, in a separate document in this Federal

Register publication, the EPA is proposing to approve the SIP revision

should adverse or critical comments be filed. Under the procedures

established in the May 10, 1994 Federal Register, this action will be

effective on November 14, 1994 unless, by October 14, 1994, adverse or

critical comments are received.

If the EPA receives such comments, this action will be withdrawn

before the effective date by publishing a subsequent notice that will

withdraw the final action. All public comments received will then be

addressed in a subsequent final rule based on this action serving as a

proposed rule. The EPA will not institute a second comment period on

this action. Any parties interested in commenting on this action should

do so at this time. If no such comments are received, the public is

advised that this action will be effective on November 14, 1994.

Nothing in this action should be construed as permitting or

allowing or establishing a precedent for any future request for a

revision to any SIP. Each request for a revision to the SIP shall be

considered separately in light of specific technical, economic, and

environmental factors, and in relation to relevant statutory and

regulatory requirements.

This action has been classified as a Table 2 action by the Regional

Administrator under the procedures published in the Federal Register on

January 19, 1989 (54 FR 2214-2225), as revised by an October 4, 1993

memorandum from Michael H. Shapiro, Acting Assistant Administrator for

Air and Radiation. The Office of Management and Budget (OMB) has

exempted this regulatory action from Executive Order 12866 review.

Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA

must prepare a regulatory flexibility analysis assessing the impact of

any proposed or final rule on small entities. 5 U.S.C. 603 and 604.

Alternatively, EPA may certify that the rule will not have a

significant economic impact on a substantial number of small entities.

Small entities include small businesses, small not-for-profit

enterprises, and government entities with jurisdiction over populations

of less than 50,000.

SIP approvals under section 110 and subchapter I, part D of the Act

do not create any new requirements, but simply approve requirements

that the State is already imposing. Therefore, because the Federal SIP-

approval does not impose any new requirements, I certify that it does

not have a significant impact on small entities affected. Moreover, due

to the nature of the Federal-state relationship under the Act,

preparation of a regulatory flexibility analysis would constitute

Federal inquiry into the economic reasonableness of state action. The

Act forbids EPA to base its actions concerning SIPs on such grounds.

Union Electric Co. v. U.S. E.P.A. , 427 U.S. 246, 256-66 (S.Ct. 1976);

42 U.S.C. section 7410(a)(2).

Under section 307(b)(1) of the Clean Air Act, petitions for

judicial review of this action must be filed in the United States Court

of Appeals for the appropriate circuit by November 14, 1994. Filing a

petition for reconsideration by the Administrator of this final rule

does not affect the finality of this rule for the purposes of judicial

review nor does it extend the time within which a petition for judicial

review may be filed, and shall not postpone the effectiveness of such

rule or action. This action may not be challenged later in proceedings

to enforce its requirements. (See section 307(b)(2).)

List of Subjects

40 CFR Part 52

Air pollution control, Hydrocarbons, Incorporation by reference,

Nitrogen dioxide, Particulate matter, Reporting and recordkeeping

requirements, Sulfur dioxide, Volatile organic compounds.

40 CFR Part 81

Air pollution control, National parks, Wilderness areas.

Dated: August 31, 1994.

Jack W. McGraw,

Acting Regional Administrator.

Chapter I, title 40 of the Code of Federal Regulations is amended

as follows:

PART 52--[AMENDED]

1. The authority citation for part 52 continues to read as follows:

Authority: 42 U.S.C. 7401-7671q.

Subpart G--Colorado

2. Section 52.320 is amended by adding paragraph (c)(65) to read as

follows:

Sec. 52.320 Identification of plan.

* * * * *

(c) * * *

(65) On January 15, 1992, March 17, 1993, and December 9, 1993, the

Governor of Colorado submitted revisions to the Colorado State

implementation plan (SIP) to satisfy those moderate PM-10 nonattainment

area SIP requirements for Aspen, Colorado due to be submitted by

November 15, 1991. Included in the December 9, 1993 submittal were PM-

10 contingency measures for Aspen to satisfy the requirements of

section 172(c)(9) of the Act due to be submitted by November 15, 1993.

(i) Incorporation by reference.

(A) Colorado Air Quality Control Commission Nonattainment Areas

regulation, all of Section III. ``Aspen/Pitkin County PM-10

Nonattainment Area'' except Section III.C.6., adopted on January 21,

1993 effective on March 2, 1993, with revisions adopted on November 12,

1993, effective on December 30, 1993.

3. Section 52.332 is amended by adding paragraph (e) to read as

follows:

Sec. 52.332 Moderate PM-10 Nonattainment Area Plans.

* * * * *

(e) On January 15, 1992, March 17, 1993, and December 9, 1993, the

Governor of Colorado submitted the moderate PM-10 nonattainment area

plan for the Aspen area. The submittals were made to satisfy those

moderate PM-10 nonattainment area SIP requirements which were due for

Aspen on November 15, 1991. The December 9, 1993 submittal was also

made to satisfy the PM-10 contingency measure requirements which were

due for Aspen on November 15, 1993.

PART 81--[AMENDED]

4. In Sec. 81.306, the Colorado PM-10 Nonattainment Areas table is

amended under Pitkin County by revising the entry for ``Aspen'' to read

as follows:

Sec. 81.306 Colorado.

* * * * *

Colorado--PM-10 Nonattainment Areas

----------------------------------------------------------------------------------------------------------------

Designation Classification

Designated area -----------------------------------------------------------------

Date Type Date Type

----------------------------------------------------------------------------------------------------------------

* * * * * * *

Pitkin County:

Aspen/Pitkin County Area.................. 11/15/90 Nonattainment........ 11/15/90 Moderate.

The area encompassed by the following

Parcel ID numbers, as defined by the

Pitkin County Planning Department:

2737-29, 2737-28, 2737-21, 2737-20,

2737-19, 2737-18, 2737-17, 2737-08,

2737-07, 2737-06, 2735-22, 2735-15,

2735-14, 2735-13, 2735-12, 2735-11,

2735-10, 2735-03, 2735-02, 2735-01,

2641-31, 2643-36, 2643-35, 2643-34,

2643-27, 2643-26.

* * * * * * *

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* * * * *

[FR Doc. 94-22525 Filed 9-13-94; 8:45 am]

BILLING CODE 6560-50-P