---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part58"
level: "part"
label: "Part 58"
heading: "Ambient Air Quality Surveillance"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part58"
sections_count: 15
---

# Part 58 — Ambient Air Quality Surveillance

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs

## Contents

- [Subpart A — General Provisions](/cfr/40/chI-subchC-part58-subpartA.md)
- [Subpart B — Monitoring Network](/cfr/40/chI-subchC-part58-subpartB.md)
- [Subpart C — Special Purpose Monitors](/cfr/40/chI-subchC-part58-subpartC.md)
- [Subpart D — Comparability of Ambient Data to the NAAQS](/cfr/40/chI-subchC-part58-subpartD.md)
- [Subpart E — Subpart E [Reserved]](/cfr/40/chI-subchC-part58-subpartE.md)
- [Subpart F — Air Quality Index Reporting](/cfr/40/chI-subchC-part58-subpartF.md)
- [Subpart G — Federal Monitoring](/cfr/40/chI-subchC-part58-subpartG.md)