[Federal Register Volume 59, Number 177 (Wednesday, September 14, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22525]


[[Page Unknown]]

[Federal Register: September 14, 1994]


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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     
------------------------------------------------------------------------
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.   
------------------------------------------------------------------------
\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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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