Document ID: EPA-R08-OAR-2015-0042-0001
Agency: epa
Document Type: Proposed Rule
Title: Air Quality State Implementation Plans; Approvals and Promulgations: State of Colorado; Second Ten-Year PM10 Maintenance Plan for Lamar
Posted Date: 2016-06-01T04:00Z

[Federal Register Volume 81, Number 105 (Wednesday, June 1, 2016)]
[Proposed Rules]
[Pages 34935-34940]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-12804]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2015-0042; FRL-9947-09-Region 8]

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: 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.

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

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2015-0042 at http://www.regulations.gov. Follow the online 
instructions for submitting comments. Once submitted, comments cannot 
be edited or removed from regulations.gov. 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 http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: James Hou, Air Program, U.S. 
Environmental Protection Agency, Region 8, Mailcode 8P-AR, 1595 Wynkoop 
Street, Denver, Colorado 80202-1129, (303) 312-6210, hou.james@epa.gov.

SUPPLEMENTARY 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 http://www.regulations.gov 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'').
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    \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.
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    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 ([mu]g/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

[[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.
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    \2\ An exceedance is defined as a daily value that is above the 
level of the 24-hour standard, 150 [mu]g/m\3\, after rounding to the 
nearest 10 [mu]g/m\3\ (i.e., values ending in five or greater are to 
be rounded up). Thus, a recorded value of 154 [mu]g/m\3\ would not 
be an exceedance since it would be rounded to 150 [mu]g/m\3\; 
whereas, a recorded value of 155 [mu]g/m\3\ would be an exceedance 
since it would be rounded to 160 [mu]g/m\3\. See 40 CFR part 50, 
appendix K, section 1.0.
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    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 [mu]g/m\3\. In 
2008 the area experienced an exceedance measured at 367 [mu]g/m\3\; in 
2009 exceedances measured at 233 [mu]g/m\3\ and 171 [mu]g/m\3\; and in 
2015 an exceedance measured at 423[mu]g/m\3\. 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]
----------------------------------------------------------------------------------------------------------------
                                                   Maximum         2nd maximum
                    Year                        concentration     concentration           Monitoring site
                                                ([mu]g/m\3\)      ([mu]g/m\3\)
----------------------------------------------------------------------------------------------------------------
2001........................................               133               111  Power Plant.
2002........................................               141               125  Power Plant.
2003........................................               132               120  Power Plant.
2004........................................                93                82  Municipal Complex.
2005........................................               116               110  Power Plant.
2006........................................               136               127  Power Plant
2007........................................                93                82  Power Plant.
2008........................................               367               123  Power Plant.
2009........................................               233               171  Power Plant.
2010........................................               136               131  Power Plant.
2011........................................               122               115  Municipal Complex.
2012........................................               147               133  Power Plant.
2013........................................               147               141  Municipal Complex.
2014........................................               129               102  Municipal Complex.
2015........................................               423                94  Municipal 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]
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                                                              24-hr PM10 Value
             Event date                   Monitoring site       ([mu]g/m\3\)                Data flag
 
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02/09/02............................  Power Plant...........               246  High Wind.
03/07/02............................  Power Plant...........               246  High Wind.
05/21/02............................  Power Plant...........               196  High Wind.
05/21/02............................  Municipal.............               183  High Wind.
06/20/02............................  Power Plant...........               181  High Wind.
06/20/02............................  Municipal.............               162  High Wind.
04/05/05............................  Power Plant...........               203  High Wind.
04/05/05............................  Municipal.............               164  High Wind.

[[Page 34937]]

 
05/22/08............................  Power Plant...........               227  High Wind.
01/19/09............................  Power Plant...........               174  High Wind.
01/19/09............................  Municipal.............               173  High Wind.
04/03/11............................  Power Plant...........               169  High Wind.
11/05/11............................  Power Plant...........               192  High Wind.
03/18/12............................  Municipal.............               242  High Wind.
04/2/12.............................  Municipal.............               163  High Wind.
02/08/13............................  Municipal.............               159  High Wind.
04/09/13............................  Municipal.............              1220  High Wind.
05/01/13............................  Municipal.............               207  High Wind.
05/24/13............................  Municipal.............               406  High Wind.
05/25/13............................  Municipal.............               168  High Wind.
05/28/13............................  Municipal.............               201  High Wind.
12/24/13............................  Municipal.............               168  High Wind.
02/16/14............................  Municipal.............               153  High Wind.
03/11/14............................  Municipal.............               387  High Wind.
03/15/14............................  Municipal.............               173  High Wind.
03/18/14............................  Municipal.............               299  High Wind.
03/29/14............................  Municipal.............               263  High Wind.
03/30/14............................  Municipal.............               264  High Wind.
03/31/14............................  Municipal.............               223  High Wind.
04/23/14............................  Municipal.............               350  High Wind.
04/29/14............................  Municipal.............               321  High Wind.
11/10/14............................  Municipal.............               298  High Wind.
04/01/15............................  Municipal.............               253  High Wind.
04/02/15............................  Municipal.............               419  High 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 [mu]g/m\3\) 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]
------------------------------------------------------------------------
                                   3-Year estimated    3-Year estimated
                                       number of           number of
       Design value period          exceedances at      exceedances at
                                      power plant      municipal complex
                                        monitor             monitor
------------------------------------------------------------------------
2001-2003.......................                 0                   0
2002-2004.......................                 0                   0
2003-2005.......................                 0                   0
2004-2006.......................                 0                   0
2005-2007.......................                 0                   0
2006-2008.......................                 0.3                 0
2007-2009.......................                 1                   0
2008-2010.......................                 1                   0
2009-2011.......................                 0.7                 0
2010-2012.......................                 0                   0
2011-2013 \3\...................                NA                   0
2012-2014 \3\...................                NA                   0
2013-2015 \3\...................                NA                   0.4
------------------------------------------------------------------------

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.
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    \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.
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    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

[[Page 34938]]

the 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 [mu]g/m\3\ and 125.6 [mu]g/m\3\, 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 [mu]g/m\3\. 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.
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    \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.
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    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 [mu]g/
m\3\ background concentration from the 137.7 [mu]g/m\3\ design value, 
which left 116.7 [mu]g/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 [mu]g/m\3\ from 2014 
forward to 2025 to arrive at a concentration of 120.8 [mu]g/m\3\. We 
then added the 21 [mu]g/m\3\ of background to this value to predict a 
total concentration in 2025 of 141.8 [mu]g/m\3\. This value is below 
the PM10 NAAQS of 150 [mu]g/m\3\ and, thus, is consistent 
with maintenance.
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    \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%.
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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

[[Page 34939]]

local 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 PM10

    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.
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    \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).
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    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: http://www.epa.gov/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\
---------------------------------------------------------------------------

    \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.
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    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

[[Page 34940]]

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 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).

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.

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

    Dated: May 19, 2016.
Shaun L. McGrath,
Regional Administrator, Region 8.
[FR Doc. 2016-12804 Filed 5-31-16; 8:45 am]
BILLING CODE 6560-50-P