; (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. (iii) Initial regulations Not later than January 1, 2026, the Administrator shall promulgate final regulations under clause (i). . 9. New fuel effects study (a) Fuel effects study (1) Study required Subject to subsection (b), the Administrator of the Environmental Protection Agency (referred to in this section as the Administrator ) shall carry out a study of the emissions effects of ethanol-blended fuels in light-duty vehicles and light-duty trucks, for the purpose of updating the Motor Vehicle Emission Simulator modeling system. (2) Requirements In designing and conducting the study under paragraph (1), the Administrator shall— (A) select test fuels that— (i) reflect a range of ethanol concentrations between 0 and at least 25 percent by volume; and (ii) are representative of fuels that are widely available on the date of enactment of this Act or reasonably could be available regionally or nationally, taking into account fuel refinery operations and economics, including the cost of reformate; (B) select test vehicles that are representative of vehicles of recent model years as of the date of enactment of this Act that include relevant technologies that are, or reasonably may come to be, in widespread use; (C) measure emission products of combustion including, at a minimum— (i) particulate matter of 2.5 micrometers in diameter or less; (ii) ultrafine particulate matter of 0.1 micrometers in diameter or less; (iii) nitrogen oxides; (iv) total hydrocarbons; (v) nonmethane organic gas; (vi) carbon monoxide; (vii) benzene; (viii) toluene; (ix) ethylbenzene; (x) xylene; (xi) 1,3-butadiene; (xii) ethanol; and (xiii) polycyclic aromatic hydrocarbons, including at a minimum benzo(a)pyrene; (D) measure the tendency of measured emissions to form secondary organic aerosols and any other relevant secondary air pollution