by the United States government, United States Code — Title 42, Chapter 85…
“ The term “standard of performance” means a requirement of continuous emission reduction, including any requirement relating to the operation or maintenance of a source to assure continuous emission reduction. (m) The term “means of emission limitation” means a system of continuous emission reduction (including the use of specific technology or fuels with specified pollution characteristics) . (n) The term “primary standard attainment date” means the date specified in the applicable implementation plan for the attainment of a national primary ambient air quality standard for any air pollutant. ”
