### IDEM INDIANA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT We ProtectHoosiers andOurEnvironment. MitchellE. DanielsJr. 100 North Senate Avenue Governor Indianapolis, Indiana 46204 (317) 232-8603 Thomas W. Easterly Toll Free (800) 451-6027 Commissioner www.idem.lN.gov

April 20, 2011

Ms. Susan Hedman Regional Administrator U.S. Environmental Protection Agency Region 5 77 West Jackson Boulevard Chicago, IL 60604-3950 Re: Requestto Parallel Process the Draft Request for Redesignation Petition and Maintenance Plan forthe Indiana Portion (Madison Township, Jefferson County and Clark and Floyd counties) ofthe Louisville KY-IN Nonattainment Area for Fine Particles Dear Ms. Hedman: The Indiana Department of Environmental Management (IDEM) submits a draft Redesignation Petition and Maintenance Plan forthe Indiana Portion (Madison Township, Jefferson County and Clark and Floyd counties) ofthe Louisville KY-IN Nonattainment Area, which was designated as nonattainment ofthe annual standard forfine particles on April 5, 2005. IDEM will conduct a public hearing concerning the Redesignation Petition and Maintenance Plan on May26, 2011, and the public comment period will conclude on May 29,2011. IDEM requests the United States Environmental Protection Agency (U.S. EPA) to parallel process this draft submittal.
The attached document consists ofthe following: 

### Redesignation Petition andMaintenance Plan • A formal requestthat the Indiana Portion (Madison Township, Jefferson County and Clark and Floyd counties) ofthe Louisville KY-IN NonattainmentArea for Fine Particles be redesignated to attainment and reclassified as maintenance. It contains and meets the requirements setforth in Section 107 ofthe Clean AirAct and in U.S. EPA Redesignation Guidance. • A maintenance year of2025 is established and 2015 and 2020 are analyzed as interim years.

• The appendices ofthe document contain historical airqualitytrend data, projected emission inventory data and thorough documentation ofthe mobile emissions analysis.

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### 0Ms. Hedman, Page 2

Motor Vehicle Emissions Budgets

• Contained in the Redesignation Petition is a new MotorVehicle Emissions Budget for 2015 and 2025. The Kentuckiana Regional Planning and Development Agency's (KIPDA's) travel demand forecasting model and the U.S. EPA software program referred to as MotorVehicle Emission Simulator (MOVES) were used to determine mobile emissions forthe annual fine particle nonattainment area. • A conservative margin of safetywas 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 MotorVehicles were used to replace the MOBILE6.2 defaultvehicle age distribution. Upon completion ofthe public participation process and documentation, IDEM will forward the official transcript and a summary and response to substantive oral and written comments underseparate cover.
IDEM requests that the U.S. EPA proceed with review and approval ofthis submittal. Ifyou have any questions or need additional information, please contact Scott Deloney, Chief, Air Programs Branch, at (317) 233-5694.
Sincerely, 

# t;fi-**B~r** Keith Baugues Assistant Commissioner Office ofAir Quality
KB/sad/ghf Enclosures: Draft Requestfor Redesignation Petition and Maintenance Plan Underthe Annual National AmbientAir Quality Standard for Fine Particles forthe Indiana Portion of the Louisville KY-IN NonattainmentArea Cc: John Summerhays, U.S. EPA Region 5 (wIenclosures) Matt Rau, U.S. EPA Region 5 (wIenclosures) John Mooney, U.S. EPA Region 5 (no enclosures) Cheryl Newton, U.S. EPA Region 5 (no enclosures) Pat Morris, U.S. EPA Region 5 (no enclosures) Cynthia Lee, LMAPCD (wI enclosures) John Gowins, KDEP (wIenclosures) Randy Simon, KIPDA (wIenclosures) Jesse Mayes, KYTC (wIenclosures) Scott Deloney, IDEM (no enclosures) Christine Pedersen, IDEM (no enclosures) Gale Ferris, IDEM (wIenclosures)