In 2007, the Tennessee Department of Transportation (TDOT) was honored by the Environmental Protection Agency (EPA) with a National Leadership Recognition Award for the innovative use of CMAQ funds to reduce diesel emissions from trucks, trains and marine vessels. The EPA recognized TDOT as the first in the nation to use federal CMAQ funds for reducing air emissions from road construction equipment and for developing the Locomotive Diesel Retrofit/Idling Reduction program.

The EPA recognition of the state includes: TDOT’s Clean Transportation Innovations Incentives program that provides CMAQ funds for retrofitting heavy-duty diesel engines in locomotives, road construction equipment and other economic sectors, TDOT’s statewide use of biodiesel in TDOT vehicles; and the state’s “Green Islands” Corridor Program which provides CMAQ funds to establish retail biofuel stations across Tennessee.

The Congestion Mitigation and Air Quality Improvement (CMAQ) program provides funds for transportation projects that reduce air emissions in air quality non-attainment and maintenance areas. The following table presents the 16 Tennessee counties that are currently eligible for CMAQ projects, and the air quality status that creates their eligibility. Some areas are eligible for CMAQ because of their air quality status for more than one pollutant.

Tennessee Counties Eligible for CMAQ Projects

The federal Clean Air Act authorizes the U.S. Environmental Protection Agency (EPA) to formally designate certain geographic regions as non-attainment areas. Air quality non-attainment areas have (or contribute to) air pollution levels higher than allowed under EPA federal air quality health standards (e.g., ozone and very fine particulate matter or PM 2.5).

In Tennessee, EPA currently designates all or part of 17 counties in five areas as non-attainment for EPA’s 8-hour ozone standard. Some of these areas include counties in neighboring states. The five 8-hour ozone non-attainment areas in Tennessee include the following counties:

Counties in three of these non-attainment areas are participating in EPA’s Early Action Compact (EAC) program. Under this program, 8-hour ozone non-attainment areas have committed to take early action to reduce emissions that contribute to ozone formation. As long as the area continues to meet EPA milestones for the EAC program, EPA will defer the effective date of the area’s non-attainment designation. Areas that maintain their EAC status are not required to complete conformity determinations, and are not eligible for projects under the Congestion Mitigation and Air Quality Improvement (CMAQ) program. However, some Early Action Compact areas are eligible for CMAQ projects based on other air quality standards (e.g., PM 2.5 non-attainment, 1-hour ozone maintenance status, 8-hour ozone maintenance status, or carbon monoxide maintenance status).

EPA also designated all or part of six counties in two areas as non-attainment for EPA’s PM 2.5 (very fine particles) standard. Some of these areas include counties in neighboring states. The two PM 2.5 non-attainment areas in Tennessee include the following counties:

After reaching attainment, areas that were once classified as non-attainment are reclassified as air quality maintenance areas. Maintenance areas are also eligible for CMAQ projects. For Montgomery County and the five counties in Middle Tennessee, their ozone maintenance status creates their CMAQ eligibility. Otherwise, they would not be eligible for CMAQ projects. Shelby County also qualifies for CMAQ projects based on 8-hour ozone non-attainment,. The maintenance areas in Tennessee are listed below.