A prior section 214 of act July 14, 1955, was renumbered section 216 by Puspan. L. 95–95 and is classified to section 7550 of this title.

Section effective Aug. 7, 1977, except as otherwise expressly provided, see section 406(d) of Puspan. L. 95–95, set out as an Effective Date of 1977 Amendment note under section 7401 of this title.

Puspan. L. 95–95, title IV, § 403(a), Aug. 7, 1977, 91 Stat. 792, directed Administrator of EPA, not later than 18 months after Aug. 7, 1977, in cooperation with National Academy of Sciences, to study and report to Congress on relationship between size, weight, and chemical composition of suspended particulate matter and nature and degree of endangerment to public health or welfare presented by such particulate matter and availability of technology for controlling such particulate matter.