Skip to Content

Proposed Rule

Approval and Promulgation of Air Quality Implementation Plans; State of Colorado; Second Ten-Year PM10

Document Details

Information about this document as published in the Federal Register.

Document Statistics
Document page views are updated periodically throughout the day and are cumulative counts for this document including its time on Public Inspection. Counts are subject to sampling, reprocessing and revision (up or down) throughout the day.
Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble


Environmental Protection Agency (EPA).


Proposed rule.


The Environmental Protection Agency (EPA) is proposing to approve State Implementation Plan (SIP) revisions submitted by the State of Colorado. On May 13, 2013, the Governor of Colorado's designee submitted to the EPA a revised maintenance plan for the Lamar area for the National Ambient Air Quality Standards (NAAQS) for particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10). EPA is proposing to approve the revised maintenance plan with the exception of one aspect of the plan's contingency measures.


Written comments must be received on or before July 1, 2016.


Submit your comments, identified by Docket ID No. EPA-R08-OAR-2015-0042 at Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.,) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit​dockets/​commenting-epa-dockets.

Start Further Info


James Hou, Air Program, U.S. Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6210,

End Further Info End Preamble Start Supplemental Information


Table of Contents

I. General Information

II. Background

III. What was the State's process?

IV. EPA's Evaluation of the Revised Lamar PM10 Maintenance Plan

V. Proposed Action

VI. Statutory and Executive Order Reviews

I. General Information

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

1. Submitting Confidential Business Information (CBI). Do not submit CBI to EPA through or email. Clearly mark the part or all of the information that you claim to be CBI. For CBI information on a disk or CD ROM that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

2. Tips for preparing your comments. When submitting comments, remember to:

  • Identify the rulemaking by docket number and other identifying information (subject heading, Federal Register volume, date, and page number);
  • Follow directions and organize your comments;
  • Explain why you agree or disagree;
  • Suggest alternatives and substitute language for your requested changes;
  • Describe any assumptions and provide any technical information and/or data that you used;
  • If you estimate potential costs or burdens, explain how you arrived at your estimate in sufficient detail to allow for it to be reproduced;
  • Provide specific examples to illustrate your concerns, and suggest alternatives;
  • Explain your views as clearly as possible, avoiding the use of profanity or personal threats; and,
  • Make sure to submit your comments by the comment period deadline identified.

II. Background

The Lamar area was designated nonattainment for PM10 and classified as moderate by operation of law upon enactment of the CAA Amendments of 1990. See 56 FR 56694, 56705, 56736 (November 6, 1991). EPA approved Colorado's nonattainment area SIP for the Lamar PM10 nonattainment area on June 9, 1994 (59 FR 29732).

On July 31, 2002, the Governor of Colorado submitted a request to EPA to redesignate the Lamar moderate PM10 nonattainment area to attainment for the 1987 PM10 NAAQS. Along with this request, the State submitted a maintenance plan, which demonstrated that the area was expected to remain in attainment of the PM10 NAAQS through 2015. EPA approved the Lamar maintenance plan and redesignation to attainment on October 25, 2005 (70 FR 61563).

Eight years after an area is redesignated to attainment, the CAA section 175A(b) requires the state to submit a subsequent maintenance plan to the EPA, covering a second 10-year period.[1] This second 10-year maintenance plan must demonstrate continued maintenance of the applicable NAAQS during this second 10-year period. To fulfill this requirement of the Act, the Governor of Colorado's designee submitted the second 10-year update of the PM10 maintenance plan to the EPA on May 13, 2013 (hereafter, “revised Lamar PM10 Maintenance Plan”).

As described in 40 CFR 50.6, the level of the national primary and secondary 24-hour ambient air quality standards for PM10 is 150 micrograms per cubic meter (μg/m[3] ). An area attains the 24-hour PM10 standard when the expected number of days per calendar year with a 24-hour concentration in excess of the standard (referred to herein as Start Printed Page 34936“exceedance”), as determined in accordance with 40 CFR part 50, appendix K, is equal to or less than one, averaged over a three-year period.[2] See 40 CFR 50.6 and 40 CFR part 50, appendix K.

Table 1 below shows the maximum monitored 24-hour PM10 values for the Lamar PM10 maintenance area for 2001 through 2015, excluding 34 values the State flagged as being caused by exceptional events. The table reflects that most of the values for the Lamar area were below the PM10 NAAQS of 150 μg/m3. In 2008 the area experienced an exceedance measured at 367 μg/m3; in 2009 exceedances measured at 233 μg/m3 and 171 μg/m3; and in 2015 an exceedance measured at 423μg/m3. Notably, the 2015 exceedance was flagged as an exceptional event due to natural high winds, but concurrence was not requested by Colorado at the time of this proposal. This exceedance did not cause a violation of the PM10 NAAQS.

Table 1—Lamar PM10 Maximum 24-Hour Values

[Based on data from power plant and municipal complex sites, AQS identification number 08-099-0001 and 08-099-0002]

YearMaximum concentration (μg/m3)2nd maximum concentration (μg/m3)Monitoring site
2001133111Power Plant.
2002141125Power Plant.
2003132120Power Plant.
20049382Municipal Complex.
2005116110Power Plant.
2006136127Power Plant
20079382Power Plant.
2008367123Power Plant.
2009233171Power Plant.
2010136131Power Plant.
2011122115Municipal Complex.
2012147133Power Plant.
2013147141Municipal Complex.
2014129102Municipal Complex.
201542394Municipal Complex.

40 CFR 50.1(j) defines an exceptional event as an event which affects air quality, is not reasonably controllable or preventable, is an event caused by human activity that is unlikely to recur at a particular location or a natural event, and is determined by the Administrator in accordance with 40 CFR 50.14 to be an exceptional event. Exceptional events do not include stagnation of air masses or meteorological inversions, meteorological events involving high temperatures or lack of precipitation, or air pollution relating to source noncompliance. 40 CFR 50.14(b) states that the EPA shall exclude data from use in determinations of exceedances and NAAQS violations where a state demonstrates to the EPA's satisfaction that an exceptional event caused a specific air pollution concentration in excess of one or more NAAQS at a particular air quality monitoring location and otherwise satisfies the requirements of section 50.14.

Throughout the years 2001 to 2014, the Lamar area monitors have recorded several exceedances of the PM10 NAAQS that have resulted from natural high wind exceptional events. The Colorado Air Pollution Control Division (APCD) flagged a total of 55 exceedances as exceptional events in the EPA's Air Quality System, which is the EPA's repository for ambient air quality data. Of these 55 flagged exceedances, the EPA has concurred on 34. Table 2 summarizes the exceptional events exceedances that the EPA has concurred on, due to the State's successful demonstrations that the exceedances were caused by natural high wind exceptional events. Thus, we are proposing to exclude 34 flagged exceedances from use in determining that Lamar continues to attain the 24-hour PM10 NAAQS. See 40 CFR 50.14(b) and (c)(2)(ii).

Table 2—Lamar PM10 EPA Approved Exceptional Events

[Based on data from power plant and municipal complex sites, AQS identification number 08-099-0001 and 08-099-0002]

Event dateMonitoring site24-hr PM10 Value (μg/m3)Data flag
02/09/02Power Plant246High Wind.
03/07/02Power Plant246High Wind.
05/21/02Power Plant196High Wind.
05/21/02Municipal183High Wind.
06/20/02Power Plant181High Wind.
06/20/02Municipal162High Wind.
04/05/05Power Plant203High Wind.
04/05/05Municipal164High Wind.
Start Printed Page 34937
05/22/08Power Plant227High Wind.
01/19/09Power Plant174High Wind.
01/19/09Municipal173High Wind.
04/03/11Power Plant169High Wind.
11/05/11Power Plant192High Wind.
03/18/12Municipal242High Wind.
04/2/12Municipal163High Wind.
02/08/13Municipal159High Wind.
04/09/13Municipal1220High Wind.
05/01/13Municipal207High Wind.
05/24/13Municipal406High Wind.
05/25/13Municipal168High Wind.
05/28/13Municipal201High Wind.
12/24/13Municipal168High Wind.
02/16/14Municipal153High Wind.
03/11/14Municipal387High Wind.
03/15/14Municipal173High Wind.
03/18/14Municipal299High Wind.
03/29/14Municipal263High Wind.
03/30/14Municipal264High Wind.
03/31/14Municipal223High Wind.
04/23/14Municipal350High Wind.
04/29/14Municipal321High Wind.
11/10/14Municipal298High Wind.
04/01/15Municipal253High Wind.
04/02/15Municipal419High Wind.

Table 3 below shows the estimated number of exceedances for the Lamar PM10 maintenance area for the three-year periods of 2001 through 2003, 2002 through 2004, 2003 through 2005, 2004 through 2006, 2005 through 2007, 2006 through 2008, 2007 through 2009, 2008 through 2010, 2009 through 2011, 2010 through 2012, 2010 through 2013, 2012 through 2014, and 2013 through 2015. To attain the standard, the three-year average number of expected exceedances (values greater than 150 μg/m3) must be less than or equal to one. The table reflects continuous attainment of the PM10 NAAQS.

Table 3—Lamar PM10 Estimated Exceedances

[Based on data from power plant and municipal complex sites, AQS identification number 08-099-0001 and 08-099-0002]

Design value period3-Year estimated number of exceedances at power plant monitor3-Year estimated number of exceedances at municipal complex monitor
2011-2013 3NA0
2012-2014 3NA0
2013-2015 3NA0.4

III. What was the State's process?

Section 110(a)(2) of the CAA requires that a state provide reasonable notice and public hearing before adopting a SIP revision and submitting it to the EPA.

The Colorado Air Quality Control Commission (AQCC) held a public hearing for the revised Lamar PM10 Maintenance Plan on December 20, 2012. The AQCC approved and adopted Start Printed Page 34938the revised Lamar PM10 Maintenance Plan during this hearing. The Governor's designee submitted the revised plan to the EPA on May 13, 2013.

We have evaluated the revised maintenance plan and have determined that the State met the requirements for reasonable public notice and public hearing under section 110(a)(2) of the CAA. On November 13, 2013, by operation of law under CAA section 110(k)(1)(B), the revised maintenance plan was deemed to have met the minimum “completeness” criteria found in 40 CFR part 51, appendix V.

IV. EPA's Evaluation of the Revised Lamar PM10 Maintenance Plan

The following are the key elements of a maintenance plan for PM10: Emission Inventory, Maintenance Demonstration, Monitoring Network/Verification of Continued Attainment, Contingency Plan, and Transportation Conformity Requirements/Motor Vehicle Emission Budget for PM10. Below, we describe our evaluation of these elements as they pertain to the revised Lamar PM10 Maintenance Plan.

A. Emission Inventory

The revised Lamar PM10 Maintenance Plan includes three inventories of daily PM10 emissions for the Lamar area, one for 2010 as the base year, one interim inventory for 2020, and one inventory for 2025 as the maintenance year. The APCD developed these emission inventories using the EPA-approved emissions modeling methods and updated transportation and demographics data. Each emission inventory lists estimated PM10 emissions for individual source categories within the Lamar PM10 maintenance area. A more detailed description of the 2010, 2020 and 2025 inventories and information on model assumptions and parameters for each source category are contained in the State's PM10 maintenance plan Technical Support Document (TSD). The inventories include the following source categories: Helicopters, construction, fuel combustion, railroads, structure fires, wood burning, paved road dust, unpaved road dust, non-road commercial equipment, non-road construction and mining equipment, non-road industrial equipment, non-road lawn and garden equipment (commercial), non-road lawn and garden equipment (residential), non-road railroad equipment, and highway vehicles. We find that Colorado has prepared adequate emission inventories for the area.

B. Maintenance Demonstration

The revised Lamar PM10 Maintenance Plan uses emissions roll-forward modeling to demonstrate maintenance of the 24-hour PM10 NAAQS through 2025. Using assumptions about the inventory source categories, the State applied the percent change in emissions for the relevant inventory source categories between 2010 and 2025 to “roll-forward” the baseline PM10 concentration. For example, the State determined that the projected growth of the emissions inventory from 2010 to 2025 is 4.8%. The growth factor was applied to the baseline design day PM10 concentration, less the background PM10 concentration, to obtain a projected PM10 concentration for the maintenance year. Using 2009 to 2011 data from the Power Plant Monitor and the Municipal Complex Monitor, the calculated PM10 maintenance concentration in the year 2025 are 140.2 μg/m3 and 125.6 μg/m3, respectively.

To account for new data acquired since the submission of the State's Plan, we evaluated the 2012-2014 data in AQS to determine whether maintenance would be demonstrated using a more recent design value as a starting point. Excluding the exceedances in 2012, 2013 and 2014 that were caused by high wind exceptional events, the EPA employed an upper tail data distribution curve fit method [4] and determined the 2012-2014 design value to be 137.7 μg/m3. As noted, the State's emissions inventories contain emissions estimates for 2010, 2020, and 2025. An examination of these inventories reveals that total emissions in 2020 represent a point on a line of near linear growth from 2015 to 2025.

Acknowledging that the State's analysis is complete, we used a roll-forward analysis in order to estimate emissions growth from 2014 to 2025 and ensure that growth in emissions would result in PM10 remaining below the NAAQS. We did this to evaluate future maintenance in light of the somewhat higher 2012-2014 design value, compared to the 2009-2011 design value Colorado evaluated. Following the same approach as Colorado, we first removed the 21 μg/m[3] background concentration from the 137.7 μg/m[3] design value, which left 116.7 μg/m[3] . Next, relying on the linear growth in emissions, we estimated 2014 emissions would grow 3.5 percent by 2025.[5] Using this factor, we projected the 116.7 μg/m3 from 2014 forward to 2025 to arrive at a concentration of 120.8 μg/m3. We then added the 21 μg/m3 of background to this value to predict a total concentration in 2025 of 141.8 μg/m3. This value is below the PM10 NAAQS of 150 μg/m3 and, thus, is consistent with maintenance.

C. Monitoring Network/Verification of Continued Attainment

In the revised Lamar PM10 Maintenance Plan, the State commits to continue to operate an air quality monitoring network in accordance with 40 CFR part 58 and the EPA-approved Colorado Monitoring SIP Element to verify continued attainment of the PM10 NAAQS. This includes the continued operation of a PM10 monitor in the Lamar area, which the State will rely on to track PM10 emissions in the maintenance area. At the time of the State's submittal, the EPA had not approved the November 21, 2011 request for removal of the Lamar Power Plant monitoring site. On August 28, 2012, EPA approved this request, and the Lamar Power Plant monitoring site ceased operations on December 31, 2012. We are proposing to approve the State's commitment as satisfying the relevant requirements.

D. Contingency Plan

Section 175A(d) of the CAA requires that a maintenance plan include contingency provisions to promptly correct any violation of the NAAQS that occurs after redesignation of an area. To meet this requirement the State has identified contingency measures along with a schedule for the development and implementation of such measures. The revised Lamar PM10 Maintenance Plan indicates that, upon notification of an exceedance of the PM10 NAAQS, the APCD and local government staff in the Lamar area will develop appropriate contingency measures intended to prevent or correct a violation of the PM10 standard. Upon a violation, a public hearing process at the State and Start Printed Page 34939local level will begin. The AQCC may endorse or approve local measures, or it may adopt State enforceable measures. The revised Lamar PM10 Maintenance Plan states that contingency measures will be adopted and fully implemented within one year of a violation.

The State identifies the following as potential contingency measures in the revised Lamar PM10 Maintenance Plan: (1) Increased street sweeping requirements; (2) additional road paving requirements; (3) more stringent street sand specifications; (4) wood burning restrictions; (5) expanded use of alternative de-icers; (6) re-establishing new source review permitting requirements for stationary sources; (7) controls at existing stationary sources; (8) transportation control measures designed to reduce vehicle miles traveled; and (9) other emission control measures appropriate for the area based on the following considerations: Cost effectiveness, PM10 emission reduction potential, economic and social concerns, and/or other factors.

We find that the contingency measures provided in the revised Lamar PM10 Maintenance Plan are sufficient and meet the requirements of section 175A(d) of the CAA.

E. Transportation Conformity Requirements: Motor Vehicle Emission Budget for PM 10

Transportation conformity is required by section 176(c) of the CAA. EPA's conformity rule at 40 CFR part 93 requires that transportation plans, programs, and projects conform to SIPs and establishes the criteria and procedures for determining whether or not they conform. Conformity to a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the NAAQS. To effectuate its purpose, the conformity rule requires a demonstration that emissions from the Regional Transportation Plan (RTP) and the Transportation Improvement Program (TIP) are consistent with the motor vehicle emissions budget(s) (MVEB(s)) contained in a control strategy SIP revision or maintenance plan (40 CFR 93.101, 93.118, and 93.124). An MVEB is defined as the level of mobile source emissions of a pollutant relied upon in the attainment or maintenance demonstration to attain or maintain compliance with the NAAQS in the nonattainment or maintenance area. Further information concerning the EPA's interpretations regarding MVEBs can be found in the preamble to the EPA's November 24, 1993, transportation conformity rule (see 58 FR 62193-62196).

The revised Lamar PM10 Maintenance Plan contains a single MVEB of 764 lbs/day of PM10 for the year 2025, the maintenance year. Once the State submitted the revised plan with the 2025 MVEB to the EPA for approval, 40 CFR 93.118 required that the EPA determine whether the MVEB was adequate.

Our criteria for determining whether a SIP's MVEB is adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4), which was promulgated August 15, 1997 (see 62 FR 43780). Our process for determining adequacy is described in our July 1, 2004 Transportation Conformity Rule Amendments (see 69 FR 40004) and in relevant guidance.[6] We used these resources in making our adequacy determination described below.

On November 15, 2013 EPA announced the availability of the revised Lamar PM10 Maintenance Plan, and the PM10 MVEB, on the EPA's transportation conformity adequacy Web site. The EPA solicited public comment on the MVEB, and the public comment period closed on December 16, 2013. We did not receive any comments. This information is available at the EPA's conformity Web site:​otaq/​stateresources/​transconf/​currsips.htm#lamar-co.

By letter to the Colorado Department of Public Health and Environment dated January 23, 2014, the EPA found that the revised Lamar PM10 Maintenance Plan and the 2025 PM10 MVEB were adequate for transportation conformity purposes.[7]

According to 40 CFR 93.118(e)(1), the EPA-approved 2015 PM10 MVEB must continue to be used for analysis years 2015 through 2024 (as long as such years are within the timeframe of the transportation plan), unless the State elects to submit a SIP revision to revise the 2015 PM10 MVEB and the EPA approves the SIP revision. The revised Lamar PM10 Maintenance Plan did not revise the previously-approved 2015 PM10 MVEB nor establish a new MVEB for 2015. Accordingly, the MVEB “. . . for the most recent prior year . . .” (i.e., 2015) from the original maintenance plan must continue to be used (see 40 CFR 93.118(b)(1)(ii) and (b)(2)(iv)).

We note that there is a considerable difference between the 2025 and 2015 budgets—764 lbs/day versus 7,534 lbs/day. This is largely an artifact of changes in the methods, models, and emission factors used to estimate mobile source emissions. The 2025 MVEB is consistent with the State's 2025 emissions inventory for vehicle exhaust and road dust, and, thus, is consistent with the State's maintenance demonstration for 2025.

The discrepancy between the 2015 and 2025 MVEBs is not a significant issue for several reasons. As a practical matter, the 2025 MVEB of 764 lbs/day of PM10 would be controlling for any conformity determination involving the relevant years because conformity would have to be shown to both the 2015 MVEB and the 2025 MVEB. Also, for any maintenance plan like the revised Lamar PM10 Maintenance Plan that only establishes a MVEB for the last year of the maintenance plan, 40 CFR 93.118(b)(2)(i) requires that the demonstration of consistency with the budget be accompanied by a qualitative finding that there are no factors that would cause or contribute to a new violation or exacerbate an existing violation in the years before the last year of the maintenance plan. Therefore, when a conformity determination is prepared which assesses conformity for the years before 2025, the 2025 MVEB and the underlying assumptions supporting it would have to be considered. Finally, 40 CFR 93.110 requires the use of the latest planning assumptions in conformity determinations. Thus, the most current motor vehicle and road dust emission factors would need to be used, and we expect the analysis would show greatly reduced PM10 motor vehicle and road dust emissions from those calculated in the first maintenance plan. In view of the above, the EPA is proposing to approve the 2025 PM10 MVEB of 764 lbs/day.

V. Proposed Action

We are proposing to approve the revised Lamar PM10 Maintenance Plan that was submitted to us on May 13, 2013, with one exception. We are not acting on the submitted update to the Natural Events Action Plan (NEAP), as the NEAP is not part of the SIP. We are proposing to approve the remainder of the revised maintenance plan because it demonstrates maintenance through 2025 as required by CAA section 175A(b), retains the control measures from the initial PM10 maintenance plan that EPA approved on October 25, 2005, and meets other CAA requirements for a section 175A maintenance plan. We are Start Printed Page 34940proposing to exclude from use in determining that Lamar continues to attain the PM10 NAAQS, exceedances of the PM10 NAAQS that were recorded at the Lamar Power Plant PM10 monitor on February 9, 2002; March 7, 2002; May 21, 2002; June 20, 2002; April 5, 2002; May 22, 2008; Jan 19, 2009; April 3, 2011; and November 5, 2011 because the exceedances meet the criteria for exceptional events caused by high wind natural events. Additionally, the EPA is proposing to exclude from use in determining that Lamar continues to attain the PM10 NAAQS, exceedances of the PM10 NAAQS that were recorded at the Municipal Complex PM10 monitor on May 21, 2002; June 20, 2002; April 5, 2005; January 19, 2009; February 8, 2013; March 18, 2012; April 2, 2012; April 9, 2013; May 1, 2013; May 24, 2013; May 25, 2013; May 28, 2013; December 24, 2013; February 16, 2014; March 11, 2014; March 15, 2014; March 18, 2014; March 29, 2014; March 30, 2014; March 31, 2014; April 23, 2014; April 29, 2014; November 10, 2014; April 1, 2015; and April 2, 2015 because the exceedances meet the criteria for exceptional events caused by high wind natural events. We are also proposing to approve the revised maintenance plan's 2025 transportation conformity MVEB for PM10 of 764 lbs/day.

VI. Statutory and Executive Orders Review

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable federal regulations (42 U.S.C. 7410(k), 40 CFR 52.02(a)). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. This proposed action merely proposes to approve state law as meeting federal requirements and does not propose to impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

  • Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);
  • does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
  • is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
  • does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Public Law 104-4);
  • does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
  • is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
  • is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
  • is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and,
  • does not provide the EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

The SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian Country, the rule does not have tribal implications and will not impose s ubstantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Start List of Subjects

List of Subjects in 40 CFR Part 52

  • Environmental protection
  • Air pollution control
  • Incorporation by reference
  • Intergovernmental relations
  • Nitrogen dioxide
  • Ozone
  • Particulate matter
  • Reporting and recordkeeping requirements
  • Volatile Organic Compounds
End List of Subjects Start Authority

Authority: 42 U.S.C. 7401 et seq.

End Authority Start Signature

Dated: May 19, 2016.

Shaun L. McGrath,

Regional Administrator, Region 8.

End Signature End Supplemental Information


1.  In this case, the initial maintenance period described in CAA section 175A(a) was required to extend for at least 10 years after the redesignation to attainment, which was effective on November 25, 2005. See 70 FR 61563. Therefore, the first maintenance plan was required to show maintenance through 2015. CAA section 175A(b) requires that the second 10-year maintenance plan maintain the NAAQS for “10 years after the expiration of the 10-year period referred to in [section 175A(a)].” Thus, for the Lamar area, the second 10-year period ends in 2025.

Back to Citation

2.  An exceedance is defined as a daily value that is above the level of the 24-hour standard, 150 μg/m3. , after rounding to the nearest 10 μg/m3. (i.e., values ending in five or greater are to be rounded up). Thus, a recorded value of 154 μg/m3. would not be an exceedance since it would be rounded to 150 μg/m3. ; whereas, a recorded value of 155 μg/m3. would be an exceedance since it would be rounded to 160 μg/m3. . See 40 CFR part 50, appendix K, section 1.0.

Back to Citation

3.  On November 21, 2011, the State of Colorado requested the removal of the Power Plant monitor due to poor citing conditions, as well as serving as a redundant monitor to the Lamar Municipal PM10 monitoring site, which is located 0.5 miles to the southeast. On August 28, 2012 the EPA concurred with the request for removal of the Lamar Power Plant PM10 SLAMS site/sampler AQS ID:08-099-0001.

Back to Citation

4.  The PM10 SIP Development Guideline indicates that the table look-up method only provides an estimation of the PM10 design value, and that more accurate design values can be obtained through the upper tail data distribution curve fit method. Further information regarding the determination of the 2012-2014 design value can be found in the March 25, 2016 memo from Richard M. Payton to the Lamar PM10 Maintenance Plan Approval Docket.

Back to Citation

5.  Total emissions in 2010 were 248.0 tons/year, while total emissions were projected to be 253.7 tons/year in 2020 and 259.9 tons/year in 2025; these values are nearly collinear. Updating the roll forward for growth from a 2014 monitored value to 2025 requires a projection of the growth in emissions from 2014 to 2025. Linear emissions growth from 2010 to 2014 is (259.9 tons/year−248.0 tons/year)*(2014-2010)/(2025-2010), or 3.2 tons/year, bringing 2014 emissions to (248.0 + 3.2) = 251.2 tons/year. Growth from 2014 to 2025, therefore, is (259.9 tons/year−251.2 tons/year)/251.2 tons/year * 100% = 3.5%.

Back to Citation

6.  “Companion Guidance for the July 1, 2004 Final Transportation Conformity Rule, Conformity Implementation in Multi-Jurisdictional Nonattainment and Maintenance Areas for Existing and New Air Quality Standards” (EPA420-B-04-012 July, 2004).

Back to Citation

7.  In a Federal Register notice dated October 3, 2014, we notified the public of our finding (see 79 FR 59767). This adequacy determination became effective on October 20, 2014.

Back to Citation

[FR Doc. 2016-12804 Filed 5-31-16; 8:45 am]