CFR›Title 40›Chapter I›Part 58›Subpart A ContainsSections 58.1–58.3CorpusDaily eCFRDisplayed edition2026-04-27Last updated2026-04-27 Subpart A—General Provisions Sections 58.1 § 58.1 Definitions. 58.2 § 58.2 Purpose. 58.3 § 58.3 Applicability. Source71 FR 61296, Oct. 17, 2006, unless otherwise noted. Next Appendix A to Part 58 Appendix A to Part 58—Quality Assurance Requirements for Monitors used in Evaluations of National Ambient Air Quality Standards