US Code

Public Law 119-73 (01/23/2026)

42 U.S.C. § 7501

Definitions

For the purpose of this part—
(1)

Reasonable further progress .—

The term “reasonable further progress” means such annual incremental reductions in emissions of the relevant air pollutant as are required by this part or may reasonably be required by the Administrator for the purpose of ensuring attainment of the applicable national ambient air quality standard by the applicable date.
(2)

Nonattainment area .—

section 7407(d) of this titleThe term “nonattainment area” means, for any air pollutant, an area which is designated “nonattainment” with respect to that pollutant within the meaning of .
(3)
The term “lowest achievable emission rate” means for any source, that rate of emissions which reflects—
(A)
the most stringent emission limitation which is contained in the implementation plan of any State for such class or category of source, unless the owner or operator of the proposed source demonstrates that such limitations are not achievable, or
(B)
the most stringent emission limitation which is achieved in practice by such class or category of source, whichever is more stringent.
In no event shall the application of this term permit a proposed new or modified source to emit any pollutant in excess of the amount allowable under applicable new source standards of performance.
(4)
section 7411(a)(4) of this title The terms “modifications” and “modified” mean the same as the term “modification” as used in .

July 14, 1955, ch. 360Pub. L. 95–95, title I, § 129(b)91 Stat. 745Pub. L. 101–549, title I, § 102(a)(2)104 Stat. 2412(, title I, § 171, as added , , ; amended , , .)

Editorial Notes

Amendments

Pub. L. 101–549, § 102(a)(2)(A)section 7410(a)(2)(I) of this title1990—, struck out “and ” after “purpose of this part”.

Pub. L. 101–549, § 102(a)(2)(B)Pars. (1), (2). , (C), amended pars. (1) and (2) generally. Prior to amendment, pars. (1) and (2) read as follows:

section 7410(a)(2)(I) of this titlesection 7502(a) of this title“(1) The term ‘reasonable further progress’ means annual incremental reductions in emissions of the applicable air pollutant (including substantial reductions in the early years following approval or promulgation of plan provisions under this part and and regular reductions thereafter) which are sufficient in the judgment of the Administrator, to provide for attainment of the applicable national ambient air quality standard by the date required in .

section 7407(d)(1) of this title“(2) The term ‘nonattainment area’ means, for any air pollutant an area which is shown by monitored data or which is calculated by air quality modeling (or other methods determined by the Administrator to be reliable) to exceed any national ambient air quality standard for such pollutant. Such term includes any area identified under subparagraphs (A) through (C) of .”

Statutory Notes and Related Subsidiaries

Effective Date

section 406(d) of Pub. L. 95–95section 7401 of this titlePart effective , except as otherwise expressly provided, see , set out as an Effective Date of 1977 Amendment note under .