# National Ambient Air Quality Standards for Ozone > **Rule** · Final rule. · Published 1997-07-18 · Effective 1997-09-16 · 62 FR 38856 ## Document - **Document number:** 97-18580 - **Category:** air-emissions - **Federal Register citation:** 62 FR 38856 - **CFR reference:** 40 CFR 50 - **Publication date:** 1997-07-18 - **Effective date:** 1997-09-16 - **EPA docket:** ADA-95-58 ## Abstract This document describes EPA's decision to revise the national ambient air quality standards (NAAQS) for ozone (O3) based on its review of the available scientific evidence linking exposures to ambient O3 to adverse health and welfare effects at levels allowed by the current O3 standards. The current 1-hour primary standard is replaced by an 8-hour standard at a level of 0.08 parts per million (ppm) with a form based on the 3-year average of the annual fourth-highest daily maximum 8-hour average O3 concentrations measured at each monitor within an area. The new primary standard will provide increased protection to the public, especially children and other at-risk populations, against a wide range of O3-induced health effects, including decreased lung function, primarily in children active outdoors; increased respiratory symptoms, particularly in highly sensitive individuals; hospital admissions and emergency room visits for respiratory causes, among children and adults with pre-existing respiratory disease such as asthma; inflammation of the lung, and possible long-term damage to the lungs. The current 1-hour secondary standard is replaced by an 8-hour standard identical to the new primary standard. The new secondary standard will provide increased protection to the public welfare against O3-induced effects on vegetation, such as agricultural crop loss, damage to forests and ecosystems, and visible foliar injury to sensitive species. EFFECTIVE DATE: This rule is effective September 16, 1997. ADDRESSES: A docket containing information relating to the EPA's review of the O3 primary and secondary standards (Docket No. A-95- 58) is available for public inspection in the Central Docket Section of the U.S. Environmental Protection Agency, South Conference Center, Room 4, 401 M St., SW., Washington, DC. This docket incorporates the docket from the previous review of the O3 standards (Doc ## Source - [Federal Register document](https://www.federalregister.gov/documents/1997/07/18/97-18580/national-ambient-air-quality-standards-for-ozone) --- *AI Analytics · CC0 1.0*