(a) Diesel fuel that has been produced to meet all of the designated alternative limits specified in subsection (b) of this section may be used to satisfy the low emission diesel fuel (LED) requirements specified in §114.312(a) of this title (relating to Low Emission Diesel Standards).(b) The designated alternative limits per gallon of LED are set forth in paragraphs (1) - (6) of this subsection:(1) An aromatic hydrocarbon content of no greater than 21.0% by weight;(2) A polycyclic aromatic hydrocarbon content of no greater than 3.5% by weight;(3) An American Petroleum Institute gravity index of no less than 36.9;(4) A cetane number of no less than 53;(5) A nitrogen content of no greater than 500 parts per million by weight (ppmw); and(6) A sulfur content of no greater than 15 ppmw.(c) Compliance with the designated alternative limits specified in subsection (b) of this section must be determined by the test methods specified in §114.315(a) of this title (relating to Approved Test Methods).