The Environmental Protection Agency (EPA) has issued a final rule amending its transportation conformity rule that sets out detailed procedures for states and local governments to ensure that transportation projects do not contribute to violations of revised air quality standards for particulate matter. 75 Fed. Reg. 14,259 (03/24/10). The amendments also address a federal appeals court decision that ordered the agency to rewrite a 2006 transportation conformity rule for fine particulate matter. Environmental Defense v. EPA, No. 06-1164 (D.C. Cir. 12/11/07). The rule, which amends 40 C.F.R. Part 93, is effective April 23, 2010.
Transportation conformity is a Clean Air Act requirement under which state and local transportation agencies must ensure that federally supported highway and transit projects are consistent with, or conform to, state implementation plans (SIPs). The projects cannot cause or contribute to new air quality violations, worsen existing violations or delay attainment of air quality standards for transportationrelated air pollutants, such as ozone, particulate matter, carbon monoxide, or nitrogen dioxide.