IDEM INDIANA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT

We Protect Hoosiers and Our Environment.

Mitchell E. Daniels Jr. 100 North Senate Avenue

Governor Indianapolis, Indiana 46204

(317) 232-8603

Thomas W. Easterly Toll Free (800) 451-6027

Commissioner www.idem.IN.gov

April 14. 2011

Ms. Susan Hedman

Regional Administrator

U.S. Environmental Protection Agency

Region 5

77 West Jackson Boulevard

Chicago, IL 60604-3950

Re: Request to Parallel Process the Draft

Request for Redesignation Petition

and Maintenance Plan Under the

Annual National Ambient Air Quality

Standard for Fine Particles for the

Central Indiana Nonattainment Area

Dear Ms. Hedman:

The Indiana Department of Environmental Management (IDEM) submits a draft

Redesignation Petition and Maintenance Plan for the Central Indiana Nonattainment

Area, which was designated as nonattainment of the annual standard for fine particles

on April 5, 2005. IDEM will conduct a public hearing concerning the Redesignation

Petition and Maintenance Plan on May 17, 2011, and the public comment period will

conclude on May 19, 2011. IDEM requests the United States Environmental Protection

Agency (U.S. EPA) to proceed with its proposed approval of IDEM's October 20, 2009

submittal and to parallel process this draft submission concurrently.

The attached document consists of the following:

Redesignation Petition and Maintenance Plan

• A formal request that the Central Indiana Area be redesignated to attainment and

reclassified as maintenance. It contains and meets the requirements set forth in

Section 107 of the Clean Air Act and in U.S. EPA Redesignation Guidance.

• A maintenance year of 2025 is established and 2015 and 2020 are analyzed as

interim years.

• The appendices of the document contain historical air quality trend data,

projected emission inventory data and thorough documentation of the mobile

emissions analysis.

Recycled Paper ('i) An E<lual Opportunity Employer Please Recycle
Ms. Hedman, Page 2

Motor Vehicle Emissions Budget

• Contained in the Redesignation Petition is a new Motor Vehicle Emissions

Budget for 2015 and 2025. The Indianapolis Department of Metropolitan

Development's travel demand forecasting model and the U.S. EPA's software

program referred to as MOBILE6.2 were used to determine emissions for the

annual fine particle nonattainment area.

• A conservative margin of safety was applied to the 2015 and 2025 projected

emissions.

• The travel demand model was updated with the best available assumptions.

• Vehicle registration data gathered from the Indiana Bureau of Motor Vehicles

were used to replace the MOBILE6.2 default vehicle age distribution.

As noted above, IDEM will conduct a public hearing on May 17, 2011 and the

public comment period will close on May 19, 2011. Upon completion of the public

participation process and documentation, IDEM will forward the official transcript and a

summary and response to substantive oral and written comments under separate cover. "- '-

IDEM request that U.S. EPA proceed with review and approval of this submittal.

If you have any questions or need additional information, please contact Scott Deloney,

Chief, Air Programs Branch, at (317) 233-5694.

Sincerely,

~~

j/ -"I Uc~12

Keith Baugues

Assistant Commissioner

Office of Air Quality

KB/sad/skr

Enclosures:

Draft Request for Redesignation Petition and Maintenance Plan Under the

Annual National Ambient Air Quality Standard for Fine Particles for the Central Indiana

Nonattainment Area

cc: John Mooney, U.S. EPA Region 5 (no enclosures)

Matt Rau, U.S. EPA Region 5 (wi enclosures)

John Summerhays, U.S. EPA Region 5 (wi enclosures)

Cheryl Newlon, U.S. EPA Region 5 (no enclosures)

Pat Morris, U.S. EPA Region 5 (no enclosures)

Scott Deloney, IDEM (no enclosures)

Christine Pedersen, IDEM (no enclosures)

Sarah Raymond, IDEM (wi enclosures)