Voglio sapere a riguardo di…

49280

Federal Register / Vol. 86, No. 168 / Thursday, September 2, 2021 / Proposed Rules
approved air quality monitoring network, and contingency provisions.
B. Conformity Under the Limited Maintenance Plan Option The transportation conformity rule and the general conformity rule set forth in the Code of Federal Regulations CFR at 40 CFR parts 51 and 93 apply to nonattainment areas and maintenance areas covered by an approved maintenance plan. Under either conformity rule, an acceptable method of demonstrating that a Federal action conforms to the applicable SIP is to demonstrate that expected emissions from the planned action are consistent with the emissions budget for the area.
While the EPAs LMP option does not exempt an area from the need to affirm conformity, it explains that the area may demonstrate conformity without conforming to an emissions budget.
Under the LMP option, emissions budgets are treated as essentially not constraining for the length of the maintenance period because it is unreasonable to expect that the qualifying areas would experience so much growth in that period that a violation of the PM10 NAAQS would result. For transportation conformity purposes, the EPA would conclude that emissions in these areas need not be capped for the maintenance period and therefore a regional emissions analysis would not be required. Similarly, Federal actions subject to the general conformity rule could be considered to satisfy the budget test specified in 40

CFR 93.158a5iA for the same reasons that the budgets are essentially considered to be unlimited.
While areas with maintenance plans approved under the LMP option are not subject to the budget test see 40 CFR
93.109e, the areas remain subject to the other transportation conformity requirements of 40 CFR part 93, subpart A. Thus, the metropolitan planning organization MPO in the area or the state must document and ensure that:
a. Transportation plans and projects provide for timely implementation of SIP transportation control measures TCMs in accordance with 40 CFR
93.113;
b. transportation plans and projects comply with the fiscal constraint element as set forth in 40 CFR 93.108;
c. the MPOs interagency consultation procedures meet the applicable requirements of 40 CFR 93.105;
d. conformity of transportation plans is determined no less frequently than every four years, and conformity of plan amendments and transportation projects is demonstrated in accordance with the timing requirements specified in 40 CFR
93.104;
e. the latest planning assumptions and emissions model are used as set forth in 40 CFR 93.110 and 40 CFR 93.111;
f. projects do not cause or contribute to any new localized carbon monoxide or particulate matter violations, in accordance with procedures specified in 40 CFR 93.123; and g. project sponsors and/or operators provide written commitments as specified in 40 CFR 93.125.

If the EPA approves the second 10year LMP, the Eagle River maintenance area will continue to be exempt from performing a regional emissions analysis but must meet project-level conformity analyses as well as the transportation conformity criteria described above.
III. Review of the States Submittal A. Qualifying for the Limited Maintenance Plan Option As discussed in Section II.A. of this preamble, the LMP Option Memo outlines the requirements for an area to qualify for an LMP. First, the area should be attaining the PM10 NAAQS.
The PM10 NAAQS is attained when the expected number of days per calendar year with a 24-hour average concentration above 150 mg/m3 is equal to or less than one 40 CFR 50.6. The Eagle River area continues to attain the standard for PM10 despite exceedances of the standard for the 24-hour average concentration in 2010, 2013 and 2019.
We have evaluated the most recent ambient air quality data for the 24-hour PM10 NAAQS and determined that the Eagle River area continues to attain the standard with the number of annual exceedances equal to 0.4 for the period 2018 through 2020. Table 1 of this preamble shows the 24-hour maximum PM10 concentrations measured at the Parkgate monitoring site from 2010
2020, which are consistently below the NAAQS.

TABLE 1PARKGATE 24-HOUR MAXIMUM PM10 CONCENTRATIONS 20102020
24-hour max g/m3

Year
lotter on DSK11XQN23PROD with PROPOSALS1

2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020

Second, the 24-hour average design value for the most recent five years of monitoring data must be at or below the critical design value of 98 mg/m3 for the PM10 NAAQS. The critical design value is a margin of safety in which an area has a one in ten probability of exceeding the NAAQS. The 5-year average design value for Eagle River, based on PM10

VerDate Sep<11>2014

16:43 Sep 01, 2021

Jkt 253001

monitoring data from 2014 through 2018, is 96 mg/m3. In addition, the EPA
also calculated the 5-year average design value for Eagle River based on PM10
monitoring data from 2016 through 2020
and found the most conservative design value estimate to be 93.4 mg/m3, which is below the critical design value of 98
mg/m3. The EPAs attainment and
PO 00000

Frm 00020

Fmt 4702

Sfmt 4702

207
108
81
174
111
90
110
63
62
168
56

2nd highest 24-hour g/m3
92
70
77
78
109
70
105
59
61
79
45

Number of days exceeding NAAQS
1 0
0 1
0 0
0 0
0 1
0

average design value evaluation used to determine if the area qualifies for the LMP option is included in the docket for this action. The EPA reviewed the data and methodology provided by the State and the most recent 5-year average design value and finds that the Eagle River areas 5-year average design value is below the critical design value of 98

E:FRFM02SEP1.SGM

02SEP1