Motor Vehicle Emission Budgets - - Approvability Review

Note: On November 23, 2011, EPA found the MVEBs in the Sacramento PM10 Maintenance Plan to be adequate. See 76 FR 72404. We are now using the adequacy 

criteria as part of our review to determine if the motor vehicle emissions budgets are approvable.

Control Strategy State Implementation Plan (SIP) Under Review: PM10

Implementation/Maintenance Plan and Redesignation Request for Sacramento County

Date of SIP Revision Receipt by EPA: 12/10/10. Additional clarification letters 

provided by the State (June 18, 2013) and the Sacramento Metropolitan Air 

Quality Management District (June 28, 2013).

Reviewer: John Ungvarsky Date: 7/12/13

Transportation Review Criteria Is Criterion

Satisfied?

Y/N

Reference in SIP Document/Comments

Sec. 93.118(e)(4)(i) The plan was endorsed by the 

Governor (or designee) and was 

subject to a public hearing.

Y The December 7, 2010 transmittal letter submitting the Sacramento PM10 Plan 

was sent by the California Air Resources Board’s (CARB’s) Executive Officer, 

James Goldstene, the Governor’s designee. The notice for the Sacramento 

Metropolitan Air Quality Management District (SMAQMD) Board hearing was 

published in the Sacramento Bee on September 27, 2010 and sent to over 2000 email addresses. The Draft Plan was made available on the District's website and 

was available for viewing at the District office on and after September 27, 2010. 

The Board of Directors for the SMAQMD held a public hearing prior to 

considering approval of this PM10 plan.

SMAQMD approved the Plan at a public hearing on October 28, 2010 and 

transmitted the Board Resolution (2010-046) with the plan and other supporting 

documentation to CARB on November 2, 2010. CARB adopted the plan, 

including a supporting PM10 transportation conformity budget, as a revision to the 

California State Implementation Plan (SIP), at a public hearing on November 18, 

2010. See CARB Resolution 10-37, which was included as enclosure IV in the 

SIP submittal package.

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.

Y The Plan uses information provided by the Sacramento Area Council of 

Governments (SACOG) and CARB. Staff consulted with SACOG during Plan 

preparations because SACOG provides vehicle activity data needed for plan 

development, and the plan sets motor vehicle emissions budgets that SACOG will 

have to meet when approving future transportation plans.

The public review process also included consultation with SACOG's Regional 

Planning Partnership (RPP) and SACOG's Climate and Air Quality Committee. 

SACOG’s RPP is an advisory group with representatives from U.S. EPA, Federal 
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Highway Administration, CalTrans, city and county transportation agencies, as 

well as business, environmental, and minority organizations and associations. The 

RPP serves as the interagency consultation process to provide comments on 

transportation conformity budgets.

CARB and SMAQMD staff addressed questions from EPA in letters provided in 

June 2013.

Sec. 93.118(e)(4)(iii) The motor vehicle emission 

budget(s) is clearly identified and 

precisely quantified.

Y Section 8, Transportation Conformity Budgets, in the Plan clearly identifies the 

MVEBs and the information used, including references, to develop the MVEBs. 

Additional information provided in CARB’s June 18, 2013 letter and SMAQMD’s 

June 28, 2013 letter further clarified and documented that when using the latest 

methodology for calculating PM10 from paved roads, the MVEBs are adequate for 

maintenance.

Sec. 93.118(e)(4)(iv) The motor vehicle 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 the given 

plan).

Y EPA has determined that the MVEBs, when considered together with all other 

emission sources, are consistent with applicable requirements for maintenance of 

the PM10 National Ambient Air Quality Standard. The MVEBs include a safety 

margin which is explained on pages 8-3 and 8-4 of the plan. The safety margins 

were included in the emissions estimates used in the maintenance demonstration. 

See page 6-2 of the plan. 

CARB’s June 13, 2013 letter provided new information regarding PM10 emissions 

from paved roads and the MVEBs. EPA had requested that CARB recalculate the 

paved road dust emissions using the latest emission factors in EPA’s Compilation 

of Air Pollutant Emission Factors (AP-42) and growth in vehicle miles traveled. 

As indicated in the June 18 letter, the recalculation resulted in a slightly lower 

emissions inventory for the paved road dust category. In their June 28, 2013 letter, 

SMAQMD indicated in the new information in the CARB letter did not change 

the overall MVEBs in the Plan. SMAQMD indicated in their letter that the slight 

reductions in emissions of 1.3 tons per day (tpd) in the 2012 inventory and 0.9 tpd 

in the 2022 inventory for paved roads should be used towards safety margins in 

the 2012 and 2022 MVEBs. The overall MVEBs in the Plan were unchanged and 

remain consistent with maintenance. 

Sec. 93.118(e)(4)(v) The plan shows a clear relationship 

among the emissions budget(s), 

control measures and the total 

emissions inventory.

Y Emissions inventory estimates are documented in Section 4, Emissions Inventory

and appendix A of the plan, and the control measures in Section 5, Control 

Measures and appendix B of the plan. The documentation in these portions of the 

plan clearly shows the relationship among the inventories, control measures, and 

MVEBs.
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Additional information provided in CARB’s June 18, 2013 letter and SMAQMD’s 

June 28, 2013 letter further clarified and documented the relationship between 

paved road dust emissions and the MVEBs.

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 VMT.

Y On November 23, 2011, EPA found the MVEBs in the Sacramento PM10 

Maintenance Plan to be adequate. See 76 FR 72404.

CARB’s June 13, 2013 letter provided new information regarding PM10 emissions 

from paved roads and the MVEBs. EPA had requested that CARB recalculate the 

paved road dust emissions using the latest emission factors in EPA’s Compilation 

of Air Pollutant Emission Factors (AP-42) and vehicle miles traveled. As 

indicated in the June 18 letter, the recalculation resulted in a slightly lower 

emissions inventory for the paved road dust category. In their June 28, 2013 letter, 

SMAQMD indicated in the new information in the CARB letter did not change 

the overall MVEBs in the Plan. SMAQMD indicated in their letter that the slight 

reductions in emissions of 1.3 tons per day (tpd) in the 2012 inventory and 0.9 tpd 

in the 2022 inventory for paved roads should be used towards safety margins in 

the 2012 and 2022 MVEBs. The overall MVEBs in the Plan were unchanged and 

remain consistent with maintenance.

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.

Y We have reviewed the comments and responses. Only one comment letter was 

received by SMAQMD on the plan. Both the comment letter and SMAQMD’s 

response was included in the submittal package. The comment did not relate to the 

MVEBs and does not affect EPA’s adequacy finding. No comments were received 

by CARB during the State review process for the plan.