Enclosure

Transportation Conformity Adequacy Review

Control Strategy State Implementation Plan (SIP) Under Review: Five Percent 

Plan for PM-10 for the Maricopa County Nonattainment Area (May 2012)

Date of SIP Revision Receipt by EPA: 5/25/12

Reviewer: Greg Nudd Date: 11/20/13

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 cover letter transmitting the SIP, dated May 25, 2012, was from Henry 

Darwin, Director, Arizona Department of Environmental Quality (ADEQ) to 

Jared Blumenfeld, Regional Administrator, US EPA Region 9. There was 

documentation in the package demonstrating that ADEQ has been designated by 

the Governor of Arizona to submit such plans to EPA. There was also information 

in the SIP package demonstrating that the Maricopa Association of Governments 

(MAG) was the appropriate agency to develop the plan for the areas of Maricopa 

County within the PM-10 nonattainment area.

A public hearing was held by MAG on April 12, 2012. Documentation of this 

hearing may be found in Appendix E of the submitted plan. 

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 During the development of the plan, the structure, approach and control measures 

were discussed and coordinated in meetings of the MAG Air Quality Technical 

Advisory Committee. The almost-final version of the plan was discussed at an 

April 26, 2012. The Air Quality Technical Advisory Committee includes 

representatives from EPA, Federal Highway Administration, Arizona Department 

of Transportation, and local governments such as Maricopa County, Phoenix, 

Mesa and smaller cities. 

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

budget(s) is clearly identified and 

precisely quantified.

Y Chapter 6 of the plan clearly quantifies and identifies the motor vehicle emissions 

budget (pp 6-42 through 6-43). MAG used MOVES 2010a to calculate PM-10 

emissions from exhaust, tire and brake wear. They used the January 2011 version 

of AP-42’s appropriate methods to calculate re-entrained dust emissions from 

paved roads and dust emissions from unpaved roads.

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 MVEB, when considered together with all other 

emission sources, are consistent with requirement to demonstrate five percent 

reductions until attainment, reasonable further progress and attainment of the PM10 standard. (See Chapters 4, 5 and 6 of the plan)
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 The on-road control measures include the use of PM-10 certified street sweepers, 

paving and stabilizing unpaved roads and alley and shoulders, reduced speed 

limits and overlaying highways with rubberized asphalt. These were implemented 

as advanced contingency measures and the reductions were not considered in 

demonstrating 5% reductions, RFP or attainment, but these controls are assumed 

in the calculation of the MVEB. (Chapter 4)

There were some ancillary benefits to the on-road emissions due to increased 

compliance with Maricopa county rules for stabilizing private unpaved roads and 

alleys. These benefits were included in the emissions inventory for the 5% 

reductions, RFP and attainment demonstrations and in the MVEBs. (Chapters 5 

and 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 VMT.

Y The previous MVEB under the approved Serious Area Plan for PM-10 was 59.7 

metric tons per day of PM-10. The budget in this plan is 54.9, which is lower due 

to changes in methodology, improvements in rule compliance and reductions due 

to paving of roads, alleys and shoulders and from improved street sweepers. 

84.6% of the on-road emissions are from re-entrained dust and dust from unpaved 

roads and alleys. These emissions are calculated using methods from AP-42. EPA 

has reviewed the AP-42 method, resulting in a more accurate, but lower estimate 

of emissions for the Maricopa County PM-10 Nonattainment Area. This 

calculation is discussed on in Chapter 5 of the 2008 Maricopa County Emissions 

Inventory which is included as Appendix A of the plan. As a result of these 

changes, the a smaller emissions budget is appropriate for the area, even though 

vehicle miles traveled is increasing. 

The other required reductions for the demonstrations in the plan were made by 

improving compliance with dust control regulations for construction projects and 

undeveloped lands. The area is also making good progress reducing road-related 

emissions by improved street sweeping and a program to pave or stabilize roads, 

alleys and shoulders.

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 MAG accepted and responded to verbal and written public comments on the plan 

as part of their public hearing process documented in Appendix E of the plan. 

MAG addressed all public comments in detail and submitted both the comments 

and their responses as part of Appendix E. EPA has reviewed these comments and 

responses and has considered them in our finding that the MVEBs are adequate.