Title 42The Public Health and WelfareRelease 119-73

§7409 National primary and secondary ambient air quality standards

Title 42 › Chapter CHAPTER 85— - AIR POLLUTION PREVENTION AND CONTROL › Subchapter SUBCHAPTER I— - PROGRAMS AND ACTIVITIES › Part Part A— - Air Quality and Emission Limitations › § 7409

Last updated Apr 6, 2026|Official source

Summary

Requires the EPA Administrator to set national air quality limits for each pollutant that already had scientific criteria by December 31, 1970. Within 30 days after December 31, 1970 the Administrator must publish proposed primary and secondary standards. After a chance for written comments, and no later than 90 days after first publishing them, the Administrator must issue final versions. For any pollutant whose criteria are issued after December 31, 1970, the Administrator must publish proposed primary and secondary standards at the same time the criteria are released and follow the same comment-and-final-rule process. Primary standards must protect public health with an adequate margin of safety. Secondary standards must protect the public welfare from known or expected harmful effects. Both kinds of standards can be changed the same way they were set. By one year after August 7, 1977 the Administrator must set a primary standard for short-term NO2 (for a period of no more than 3 hours) unless the scientific criteria show there is no significant evidence that such a standard is needed. By December 31, 1980 and every five years after, the Administrator must review the scientific criteria and the standards and update them or make new ones as needed, and may do reviews more often. The Administrator must also appoint an independent seven-member scientific review committee (including at least one National Academy of Sciences member, one physician, and one state air pollution official). By January 1, 1980 and every five years after, that committee must review the criteria and standards, recommend changes, and advise on research needs, natural versus human pollution sources, and any health, welfare, social, economic, or energy effects of ways to meet the standards.

Full Legal Text

Title 42, §7409

The Public Health and Welfare — Source: USLM XML via OLRC

(a)(1)The Administrator—
(A)within 30 days after December 31, 1970, shall publish proposed regulations prescribing a national primary ambient air quality standard and a national secondary ambient air quality standard for each air pollutant for which air quality criteria have been issued prior to such date; and
(B)after a reasonable time for interested persons to submit written comments thereon (but no later than 90 days after the initial publication of such proposed standards) shall by regulation promulgate such proposed national primary and secondary ambient air quality standards with such modifications as he deems appropriate.
(2)With respect to any air pollutant for which air quality criteria are issued after December 31, 1970, the Administrator shall publish, simultaneously with the issuance of such criteria and information, proposed national primary and secondary ambient air quality standards for any such pollutant. The procedure provided for in paragraph (1)(B) of this subsection shall apply to the promulgation of such standards.
(b)(1)National primary ambient air quality standards, prescribed under subsection (a) shall be ambient air quality standards the attainment and maintenance of which in the judgment of the Administrator, based on such criteria and allowing an adequate margin of safety, are requisite to protect the public health. Such primary standards may be revised in the same manner as promulgated.
(2)Any national secondary ambient air quality standard prescribed under subsection (a) shall specify a level of air quality the attainment and maintenance of which in the judgment of the Administrator, based on such criteria, is requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air. Such secondary standards may be revised in the same manner as promulgated.
(c)The Administrator shall, not later than one year after August 7, 1977, promulgate a national primary ambient air quality standard for NO2 concentrations over a period of not more than 3 hours unless, based on the criteria issued under section 7408(c) of this title, he finds that there is no significant evidence that such a standard for such a period is requisite to protect public health.
(d)(1)Not later than December 31, 1980, and at five-year intervals thereafter, the Administrator shall complete a thorough review of the criteria published under section 7408 of this title and the national ambient air quality standards promulgated under this section and shall make such revisions in such criteria and standards and promulgate such new standards as may be appropriate in accordance with section 7408 of this title and subsection (b) of this section. The Administrator may review and revise criteria or promulgate new standards earlier or more frequently than required under this paragraph.
(2)(A)The Administrator shall appoint an independent scientific review committee composed of seven members including at least one member of the National Academy of Sciences, one physician, and one person representing State air pollution control agencies.
(B)Not later than January 1, 1980, and at five-year intervals thereafter, the committee referred to in subparagraph (A) shall complete a review of the criteria published under section 7408 of this title and the national primary and secondary ambient air quality standards promulgated under this section and shall recommend to the Administrator any new national ambient air quality standards and revisions of existing criteria and standards as may be appropriate under section 7408 of this title and subsection (b) of this section.
(C)Such committee shall also (i) advise the Administrator of areas in which additional knowledge is required to appraise the adequacy and basis of existing, new, or revised national ambient air quality standards, (ii) describe the research efforts necessary to provide the required information, (iii) advise the Administrator on the relative contribution to air pollution concentrations of natural as well as anthropogenic activity, and (iv) advise the Administrator of any adverse public health, welfare, social, economic, or energy effects which may result from various strategies for attainment and maintenance of such national ambient air quality standards.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

Codification Section was formerly classified to section 1857c–4 of this title.

Prior Provisions

A prior section 109 of act July 14, 1955, was renumbered section 116 by Pub. L. 91–604 and is classified to section 7416 of this title.

Amendments

1977—Subsec. (c). Pub. L. 95–95, § 106(b), added subsec. (c). Subsec. (d). Pub. L. 95–95, § 106(a), added subsec. (d).

Statutory Notes and Related Subsidiaries

Effective Date

of 1977 AmendmentAmendment by Pub. L. 95–95 effective Aug. 7, 1977, except as otherwise expressly provided, see section 406(d) of Pub. L. 95–95, set out as a note under section 7401 of this title. Modification or Rescission of Rules,

Regulations

, Orders, Determinations, Contracts, Certifications, Authorizations, Delegations, and Other ActionsAll rules,

Regulations

, orders, determinations, contracts, certifications, authorizations, delegations, or other actions duly issued, made, or taken by or pursuant to act
July 14, 1955, the Clean Air Act, as in effect immediately prior to the date of enactment of Pub. L. 95–95 [Aug. 7, 1977] to continue in full force and effect until modified or rescinded in accordance with act
July 14, 1955, as amended by Pub. L. 95–95 [this chapter], see section 406(b) of Pub. L. 95–95, set out as an

Effective Date

of 1977 Amendment note under section 7401 of this title. Termination of Advisory CommitteesAdvisory committees established after Jan. 5, 1973, to terminate not later than the expiration of the 2-year period beginning on the date of their establishment, unless, in the case of a committee established by the President or an officer of the Federal Government, such committee is renewed by appropriate action prior to the expiration of such 2-year period, or in the case of a committee established by the Congress, its duration is otherwise provided for by law. See section 1013 of Title 5, Government Organization and Employees. Role of Secondary Standards Pub. L. 101–549, title VIII, § 817, Nov. 15, 1990, 104 Stat. 2697, provided that: “(a) Report.—The Administrator shall request the National Academy of Sciences to prepare a report to the Congress on the role of national secondary ambient air quality standards in protecting welfare and the environment. The report shall:“(1) include information on the effects on welfare and the environment which are caused by ambient concentrations of pollutants listed pursuant to section 108 [42 U.S.C. 7408] and other pollutants which may be listed; “(2) estimate welfare and environmental costs incurred as a result of such effects; “(3) examine the role of secondary standards and the State implementation planning process in preventing such effects; “(4) determine ambient concentrations of each such pollutant which would be adequate to protect welfare and the environment from such effects; “(5) estimate the costs and other impacts of meeting secondary standards; and “(6) consider other means consistent with the goals and objectives of the Clean Air Act [42 U.S.C. 7401 et seq.] which may be more effective than secondary standards in preventing or mitigating such effects. “(b) Submission to Congress; Comments; Authorization.—(1) The report shall be transmitted to the Congress not later than 3 years after the date of enactment of the Clean Air Act

Amendments

of 1990 [Nov. 15, 1990]. “(2) At least 90 days before issuing a report the Administrator shall provide an opportunity for public comment on the proposed report. The Administrator shall include in the final report a summary of the comments received on the proposed report. “(3) There are authorized to be appropriated such sums as are necessary to carry out this section.”

Reference

Citations & Metadata

Citation

42 U.S.C. § 7409

Title 42The Public Health and Welfare

Last Updated

Apr 6, 2026

Release point: 119-73