US lawFederal (United States)RegulationsTitle 40 CFR — Protection of EnvironmentChapter I — ENVIRONMENTAL PROTECTION AGENCYPart 51 — REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANSSubpart J — Ambient Air Quality Surveillance51.19040 C.F.R. § 51.190Ambient air quality monitoring requirements.Last amended: 2016Year: 2026Length: 29 wordsOfficial source Cite as 40 C.F.R. § 51.190 (2026)The requirements for monitoring ambient air quality for purposes of the plan are located in subpart C of part 58 of this chapter. [44 FR 27569, May 10, 1979]