UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

Mr. Barry R. Wallerstein Co-President and Co-Chair NACAA Mobile Sources and Fuels Committee National Association ofClean Air Agencies 444 North Capitol Street,NW Washington, D.C. 20001 Dear Mr. Wallerstein: 

## MAR 2 52013

OFFICE OF AIR AND RADIATION

Thank you for your letter ofJanuary 22, 2013 , co-signed by Ms
.Nancy Seidman, to the U.S. Environmental Protection Agency, urging the proposal of"Tier 3" light-duty vehicle emissions and gasoline standards and finalization ofthese standards by December 31, 2013. The
.EPA is developing the Tier 3 standards to respond to the critical need to improve air quality and to enable a harmonized national vehicle emissions control program. The EPA shares your goal ofreducing air pollution across the United States. The Tier 3 standards have the potential to achieve significant benefits. As mentioned in your letter, state and local agencies are challenged with finding effective emission reduction measures to meet their clean air obligations. This Tier 3 rule would reduce motor vehicle emissions and help state and local areas attain and maintain the existing health-based air quality standards in a cost-effective and timely way. The reductions in ozone and particulate matter would avoid premature mortality and other health impacts, including respiratory symptoms in children and exacerbation ofasthma. The Tier 3 standards would, when finalized, create a comprehensive regulatory approach that provides certainty for both the auto and oil industries. Under a single harmonized national vehicle program, the Tier 3 standards under consideration would provide for coordinated implementation with the California vehicle program and the EPA and Department ofTransportation's recently finalized light-duty vehicle standards to reduce carbon pollution and improve fuel economy for model years 2017 through 2025
. A timely Tier 3 program is critical to addressing the impacts ofmotor vehicles on air quality and public health; therefore, we intend to issue proposed Tier 3 standards in March of2013 and finalize these standards by the end of2013.

Internet Address (URL) • http://www.epa.gov Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Postconsumer, Process Chlorine Free Recycled PaperWe appreciate your bringing the Navigant Economics study to our attention, and we will consider this study as we develop the final rulemaking. Again, thank you for your letter and for your continued support ofthe Tier 3 program. I appreciate your commitment to achieving clean air for all citizens, and I look forward to continuing to work together towards that goal.

cc: Mr
. William Becker Executive Director Sincerely,

i a McCarthy Assistant AdministratorNancy L. Seidman UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 

## MAR 2 52013

Co-ChairNACAA Mobile Sources and Fuels Committee National Association ofClean Air Agencies 444 North Capitol Street, NW Washington, D.C. 20001 Dear Ms
. Seidman: OFFICE OF AIR AND RADIATION

Thank you for your letter ofJanuary 22, 2013 , co-signed by Mr. Barry Wallerstein, to the U.S. Environmental Protection Agency, urging the proposal of"Tier 3" light-duty vehicle emissions and gasoline standards and finalization ofthese standards by December 31 , 2013. The EPA is developing the Tier 3 standards to respond to the critical need to improve air quality and to enable a harmonized national vehicle emissions control program. The EPA shares your goal ofreducing air pollution across the United States. The Tier 3 standards have the potential to achieve significantbenefits. As mentioned in your letter, state and local agencies are challenged with finding effective emission reduction measures to meet their clean air obligations. This Tier 3 rule would reduce motor vehicle emissions and help state and local areas attain and maintain the existing health-based air quality standards in a cost-effective and timely way. The reductions in ozone and particulate matter would avoid premature mortality and other health impacts, including respiratory symptoms in children and exacerbation ofasthma
. The Tier 3 standards would, when finalized, create a comprehensive regulatory approach that provides certainty for both the auto and oil industries. Under a single harmonized national vehicle program, the Tier 3 standards under consideration would provide for coordinated implementation with the California vehicle program and the EPA and Department ofTransportation's recently finalized light-duty vehicle standards to reduce carbon pollution and improve fuel economy for model years 2017 through 2025. A timely Tier 3 program is critical to addressing the impacts ofmotor vehicles on air quality and public health; therefore, we intend to issue proposed Tier 3 standards in March of2013 and finalize these standards by the end of2013.

Internet Address (URL) • http://www.epa.gov Recycled/Recyclable • Printed with Vegetable Oil Based Inks on 100% Postconsumer, Process Chlorine Free Recycled PaperWe appreciate your bringing the Navigant Economics study to our attention, and we will consider this study as we develop the final rulemaking
. Again, thank you for your letter and for your continued support ofthe Tier 3 program. I appreciate your commitment to achieving clean air for all citizens, and I look forward to continuing to work together towards that goal. Sincerely,

ina McCarthy Assistant Administrator