1

Memorandum

Date: July 1, 2015

R e : EPA’s Adequacy Review of Motor Vehicle Emissions Budgets in Mammoth

Lakes PM10 Maintenance Plan

To: Docket Number EPA

- R09

- OAR

- 201 5

- 0 279; Docket for the Mammoth Lakes,

California PM10 Maintenance Plan and Redesignation Request ; Proposed Approval Action

From: Jerry Wamsley , Air Planning Office, U.S. E nvironmental P rotection A gency

Region 9

Summary

Together with EPA’s proposed rulemaking, t his memorandum provides the documentation for

EPA’s a dequacy determination for the Mammoth Lakes 2012 and 2030 PM10 Motor Vehicle Emissions Budgets ( MVEB s, also referred to as budgets) in the Great Basin Unified Air Pollution Control District’s (GBUAPCD) “2014 Air Quality Maintenance Plan and Redesignation R equest for the Town of Mammoth Lakes” (Mammoth Lakes PM10 Maintenance Plan)

, adopted on May 5, 2014 and later submitted b y California to EPA on October 21, 2014.

The MVEB adequacy criteria are specified in 40 CFR 93.118(e)(4) and 93.118(e)(5). There are

s even criteria EPA must certify in finding an MVEB adequate. In support of our proposed approval and finding of adequacy for the Mammoth Lakes area PM10 MVEBs, we have

determined that the State has met all of these criteria. Our detailed disc ussion follows below. Where noted, more detail can be found in our proposed action and in the Mammoth Lakes PM10

Maintenance Plan.

Criterion #1, Sec. 93.118(e)(4)(i) : The plan was endorsed by the Governor (or designee) and was subject to a public hea ring

.

The GBUAPCD and the California Air Resources Board (CARB) satisfied applicable statutory and regulatory requirements for reasonable public notice and hearing prior to adoption and submittal of “2014 Air Quality Maintenance Plan and Redesignation Req uest for the Town of Mammoth Lakes”. The GBUAPCD and the State both provided separate 30

- day public comment period s , and held a public hearing prior to the adoption of the Plan on May 5, 2014 and September 18, 2014, respectively. Documentation accompanyi ng the SIP and provided in the docket for our proposal describes a public and agency outreach effort. See, e.g., the respective Public Hearing Notices and Proof of Publication provided by GBUAPCD and CARB , as well as CARB’s partial hearing transcript

.2

Criterion #2, Sec. 93.118(e)(4)(ii) : The plan was developed through consultation with federal, state and local agencies; full implementation plan documentation was provided and EPA’s stated concerns, if any, were addressed.

GBUAPCD and CARB consulted w ith federal, state and local agencies in April, May, August and September of 2014 . This consultation included EPA, CARB, and California Department of Transportation (Cal t rans)

. EPA received several draft versions of the Mammoth Lakes PM10

Maintenance Plan and provided comments prior to adoption

. As result of EPA comments d uring

GBUAPCD’s 30

- day comment period prior to District Board adoption on May 5, 2014, District staff amended the budgets to include the entire non

- attainment area as opposed to the Township

of Mammoth Lakes area

. Consequently, the budget s considered and adopted by the District

Board and transmitted to CARB w ere not the budget s initially released to the general public at the start of the District’s public comment period. To comply f ully with public notice requirements for SIP revisions prior to submittal by the State, CARB provided a full 30

- day comment period and public hearing for GBUAPCD Board adopted version of the Mammoth Lakes PM10 Maintenance Plan and the budgets contained the rein. For the budgets as presented and adopted by CARB, see their “Staff Report: Town of Mammoth Lakes PM10 Maintenance Plan and Redesignation Request”, dated August 18, 2014 at Table 3, page 10, provided in the

docket for this action. Again, for eviden ce of CARB’s public notice and hearing see CARB’s

documentation included in the docket for this action.

In sum, i ssu es raised by EPA on the draft Mammoth Lakes PM10 M aintenance P lan were fully

addressed by GBUAPCD in the ir adopted maintenance plan and CARB ’s public hearing ensured the GBUAPCD amendments met public notice requirements for SIPs.

Criterion #3, Sec. 93.118(e)(4)(iii) : The motor vehicle emission budgets are clearly identified and precisely quantified.

The motor vehicle emissions budgets for 2012 and 2030 are clearly identified and precisely quantified on page 47 of the Mammoth Lakes PM10 Maintenance Plan; see also Tables 5

- 7, 8

- 1,

and 8

- 3, pages 22, 36, and 37, respectively. Also, see the CARB’s “Staff Report: Town of

Mammoth Lakes PM10 Maintenance Plan and Redesignation Request”, dated August 18, 2014 at Table 3, page 10. The budgets were developed using CARB’s EMFAC2011 motor vehicle

emissions factor model and EPA’s Compilation of Air Pollutant Emission Factors ( AP

- 42 )

. Chapter 5 of the Maintenance Plan documents the methods and assumptions underlying the emission inventory estimates used in developing the budgets.

Table 1 : Mammoth Lakes PM10 Maintenance Plan 2012 and 2030 PM10 Motor Vehicle Emissions Budgets (kilograms/day)

Sourc e Category 2012 2030

Entrained Road Dust Cinders/Paved Roads 3,455 4,305

On

- road Mobile Sources ( exhaust, tailpipe, tire and brake wear) 11 14

Total Motor Vehicle Emissions Budget 3,466 4, 31 9

Peak 24

- hour winter PM10 emissions calculated for the entire planning area. Source: Mammoth Lakes PM10 Maintenance Plan, Tables 5

- 7, 8

- 1, and 8

- 3, pages 22, 36, and 37, respectively; also, see page 47.3

Criterion #4, Sec. 93.118(e)(4)(iv) : The motor vehic le emissions budget(s), when considered together with all other emission sources, is consistent with applicable requirements for reasonable further progress, attainment, or maintenance (whichever is relevant to a given implementation plan submission )

.

EPA has concluded that the budget s for the years 2012 and 2030 when considered together with all other emission sources is consistent with the requirement to demonstrate maintenance of the

24

- hour PM10 standard in the Mammoth Lakes area. This finding is base d on our review of

GBUAPCD’s maintenance demonstration and budgets in the Mammoth Lakes PM10

Maintenance Plan.

For reasons related to the topography, economy, and winter time meteorology of the Mammoth Lakes area, GBUAPCD modeled w ithin the maintenance demonstration an area equivalent to the Township of Mammoth Lakes boundaries and smaller than the total nonattainment area

. Nominally, this resulted in budgets approximately 22 percent smaller than the calculated total

nonattainment area budgets . GBUAPCD modeled two scenarios in its Township

- based maintenance demonstration with the second scenario involving high est PM emissions from entrained road dust on paved roads being most relevant to the adopted budgets . Within the

maintenance demonstration and the second scenario of highest entrained road dust emissions, the predicted 2030 PM10 concentration was 104.8 micrograms per cubic meter (μg/m 3 ), well below the standard of 150 μg/m 3

.

In response to EPA comments, GBUAPCD revised their budgets for 2012 and 2030 t o include vehicle miles traveled and resulting direct and fugitive mobile source PM10 emissions from mobile sources east of the Township and representing the entire nonattainment area

. Using the same background and proportionality inputs to the mode l from the second scenario of highest

entrained road dust emissions provided in Chapter 8.3 of the Mammoth Lakes PM10 Maintenance Plan, we modeled the 2030 PM10 ambient concentration using the total

nonattainment area budgets provided by GBUAPCD and the re sult was 104.8 μg/m 3 ; the same predicted concentration as the plan’s maintenance demonstration.

The calculation is as follows:

C d = design day concentration = 99 μg/m 3 ;

C b = background concentration = 5 μg/m 3 (resulting in 94 μg/m 3 for allocation among emission sources);

C d RWB = design day concentration attributed to residential wood burning = (94 μg/m 3 )(0.61) = 57.3 μg/m 3 ;

C d MS = design day concentration attributed to mobile sources (direct PM10 and entrained road dust) = (94 μg/m 3 )(0.39) = 36.7 μg/m 3 ;

C RWB = 2030 concentration due to residential wood burning = (C d RWB ) (E 2030 /E 2012 ) = (57.3 μg/m 3 )(802 kilograms/day (kg/day) / 850 kg/day) = 53.9 μg/m 3 , where E
xxxx is estimated emissions;

C MS = 2030 concentration due to entrained road dust = (C d MS ) (E 2030 /E 2012 ) = (36.7 μg/m 3 )(4319 kg/day / 3466 kg/day) = 45.9 μg/m 3 , where E
xxxx is estimated emissions;4

C Total = total 2030 concentration = C b + C RWB + C MS = 5 μg/m 3 + 53.9 μg/m 3 + 45.9 μg/m 3 = 104.8 μg/m 3 (all other source contributions were neglible, e.g., very low stationary source emissions are not predicted to change )

.

To conclude, w e found that the predicted concentration was well below the standard and

consistent with the concentration calculated in the maintenance demonstration for the same

scenario

. See our proposed action on the Mammoth Lakes PM10 Maintenance Plan for our

detailed review of the emission s inventory and maintenance demonstration.

Criterion #5, Sec. 93.118(e)(4)(v) : The plan shows a clear relationship among the emissions budget(s), control measures and the total emissions inventory.

The emission inventories for all point, area, and mobile sources within the Mammoth Lakes nonattainment area are contained in Chapter 5 of the Mammoth Lakes PM10 Maintenance Plan. Chapter 7 d escribes the control measures implemented in the Mammoth Lakes area and Chapter

8 details control measure effects in the maintenance demonstration. Tables 5

- 7, 8

- 1 and 8

- 3 best illustrate the relationships between the 2012 base year emissions inventory, t he projected 2030 emissions inventory, and the implemented control measures.

The motor vehicle emissions budget s for PM 10 represent the sum of emissions estimates for certain motor vehicle related source categorie s includ ing emissions from entrained roa d dust (paved ) , vehicle exhaust, brake wear, and tire wear

. Where applicable, these emissions estimates

show the effect of control measures implemented previously and maintained as part of the

Maintenance Pl an, particularly those related to entrained road dust. As discussed in the Mammoth Lakes PM10 Maintenance Plan and our proposed action, due to the wet and cold wintertime conditions, the budgets do not include entrained dust from unpaved roads,

construction dust.

Criterion 6, Sec. 93.118(e)(4)(vi) : Revisions to previously submitted control strategy or maintenance plans explain and document any changes to any previous submitted budgets and control measures; impacts on point and area source emissions; any changes to established safety margins (see § 93.101 for definition), and reasons for the changes (including the basis for any changes to emission factors or estimates of vehicle miles traveled).

The 199 0 PM10 Air Quality Management Plan for Mammoth Lakes, previously approved by

EPA in 1996

, did not contain motor vehicle emissions budgets, as EPA had not promulgated the conformity regulations required by the 199 0 Clean Air Act Amendments

. So while the October

2014 submitted Mammoth Lakes PM10 Maintenance Plan provides for 2012 and 2030 emissions budg ets, i t d oes not update or revise any budget for conformity purposes.5

Criterion 7, Sec. 93.118(e)(5 ) : EPA has reviewed the State’s compilation of public comments and response to comments that are required to be submitted with any implementation plan.

Besides EPA, n o one commented on the Mammoth Lakes PM10 M aintenance P lan and redesignation request during either the State’s, or the District’s public review process. See the docket for the public comments summary or CARB’s partial hearing transcript. EPA’s comments were fully addressed by GBUAPCD and CARB.