; and (II) provide that any such credits shall expire after not more than 5 years. (2) Clean octane (A) Prohibition Effective January 1, 2023, no refiner or importer shall introduce any source of octane value into motor vehicle gasoline with a research octane number of 98 or higher unless such source of octane value has average lifecycle greenhouse gas emissions, as determined by the Secretary of Energy using the version of the Argonne National Laboratory Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model in effect as of the date of enactment of the Next Generation Fuels Act of 2020 , that are at least 30 percent less than the baseline lifecycle greenhouse gas emissions. (B) Regulations (i) Promulgation The Administrator of the Environmental Protection Agency shall promulgate regulations to implement this paragraph. Not later than January 1, 2023, the Administrator shall promulgate final regulations under the preceding sentence. (ii) Contents The regulations to implement this paragraph shall— (I) determine the baseline lifecycle greenhouse gas emissions for purposes of this paragraph; (II) determine the average lifecycle greenhouse gas emissions of sources of octane value for purposes of this paragraph; and (III) ensure that the requirements of this paragraph are met. (3) Definitions In this subsection, the terms baseline lifecycle greenhouse gas emissions , lifecycle greenhouse gas emissions , and research octane number have the meanings given to those terms in section 101 of the Next Generation Fuels Act of 2020 . . (b) Reformulated gasoline Clause (ii) of section 211(k)(3)(A) of the Clean Air Act is ( 42 U.S.C. 7545(k)(3)(A) ) is amended to read as follows: (ii) Aromatics The aromatic hydrocarbon content of the reformulated gasoline— (I) shall not exceed 25 percent by volume