{"data":{"id":"us/40-cfr-50.16","jurisdiction":"us","citation":"40 CFR 50.16","heading":"National primary and secondary ambient air quality standards for lead.","body":"(a) The national primary and secondary ambient air quality standards for lead (Pb) and its compounds are 0.15 micrograms per cubic meter, arithmetic mean concentration over a 3-month period, measured in the ambient air as Pb either by:\n(1) A reference method based on appendix G of this part and designated in accordance with part 53 of this chapter or;\n(2) An equivalent method designated in accordance with part 53 of this chapter.\n(b) The national primary and secondary ambient air quality standards for Pb are met when the maximum arithmetic 3-month mean concentration for a 3-year period, as determined in accordance with appendix R of this part, is less than or equal to 0.15 micrograms per cubic meter.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER C—AIR PROGRAMS","PART 50—NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"019f4747a51f87bf35b2b67cb8a74e8cdea8043862fbe3c3da9bbaf2bf0d2d93","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-50.15","next":"us/40-cfr-50.17"},"notice":"GroundRules: Original legal text. Not legal advice."}