ANTI-BACKSLIDING.

SEC. 209. ANTI-BACKSLIDING. Section 211 of the Clean Air Act (42 U.S.C. 7545) is amended by adding at the end the following:“(v) Prevention of Air Quality Deterioration.—“(1) Study.—“(A) In general.—Not later than 18 months after the date of enactment of this subsection, the Administrator shall complete a study to determine whether the renewable fuel volumes required by this section will adversely impact air quality as a result of changes in vehicle and engine emissions of air pollutants regulated under this Act.“(B) Considerations.—The study shall include consideration of—“(i) different blend levels, types of renewable fuels, and available vehicle technologies; and“(ii) appropriate national, regional, and local air quality control measures.“(2) Regulations.—Not later than 3 years after the date of enactment of this subsection, the Administrator shall—121 STAT. 1532 “(A) promulgate fuel regulations to implement appropriate measures to mitigate, to the greatest extent achievable, considering the results of the study under paragraph (1), any adverse impacts on air quality, as the result of the renewable volumes required by this section; or“(B) make a determination that no such measures are necessary.”.