40 CFR Part 50 — National Primary and Secondary Ambient Air Quality Standards
- § 50.1— Definitions.
- § 50.2— Scope.
- § 50.3— Reference conditions.
- § 50.4— National primary ambient air quality standards for sulfur oxides (sulfur dioxide).
- § 50.5— National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).
- § 50.6— National primary and secondary ambient air quality standards for PM<sub>10</sub>.
- § 50.7— National primary and secondary ambient air quality standards for PM<sub>2.5</sub>.
- § 50.8— National primary ambient air quality standards for carbon monoxide.
- § 50.9— National 1-hour primary and secondary ambient air quality standards for ozone.
- § 50.10— National 8-hour primary and secondary ambient air quality standards for ozone.
- § 50.11— National primary and secondary ambient air quality standards for oxides of nitrogen (with nitrogen dioxide as the indicator).
- § 50.12— National primary and secondary ambient air quality standards for lead.
- § 50.13— National primary and secondary ambient air quality standards for PM<sub>2.5</sub>.
- § 50.14— Treatment of air quality monitoring data influenced by exceptional events.
- § 50.15— National primary and secondary ambient air quality standards for ozone.
- § 50.16— National primary and secondary ambient air quality standards for lead.
- § 50.17— National primary ambient air quality standards for sulfur oxides (sulfur dioxide).
- § 50.18— National primary ambient air quality standards for PM<sub>2.5</sub>.
- § 50.19— National primary and secondary ambient air quality standards for ozone.
- § 50.20— National primary ambient air quality standards for PM<sub>2.5</sub>.
- § 50.21— National secondary ambient air quality standards for sulfur oxides (sulfur dioxide).