federal_register: 96-30903
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| 96-30903 | National Ambient Air Quality Standards for Ozone: Proposed Decision | Proposed Rule | In accordance with sections 108 and 109 of the Clean Air Act (Act), EPA has reviewed the air quality criteria and national ambient air quality standards (NAAQS) for ozone (O<INF>3) and particulate matter (PM). Based on these reviews, the EPA proposes to change the standards for both classes of pollutants. This document describes EPA's proposed changes with respect to the NAAQS for O<INF>3. The EPA's proposed actions with respect to PM are being proposed elsewhere in today's Federal Register. Nonetheless, EPA has concluded that the effects and control of each are in many instances linked and will be affected by the other. For this reason, EPA intends to review and, as appropriate, modify both standards on a similar schedule, with promulgation of revised O<INF>3 standards in June of 1997, concurrent with promulgation of revised standards for PM. Doing so will permit States, localities and industry to address the control of these and related pollutants on a more consistent basis. Ozone and related pollutants have long been recognized, in both clinical and epidemiological research, to affect public health. The proposed revised standard would provide protection for children and other at-risk populations against a wide range of O<INF>3-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. With respect to O<INF>3, EPA proposes to change the current primary standard (last modified in 1979) in several respects: 1. Since longer exposure periods are of greater concern at lower O<INF>3 concentrations, attainment of the standard would no longer be based upon 1-hour averages, but instead on 8-hour averages. This improvement was unanimously recommended by EPA's Clean Air Scientific Advisory Committee (CASAC). 2. As a result of this change in averaging time, the level of the standard would be lowered from the present 0.12 parts per million (ppm). The EPA solicits comment on alternative levels of 0.09 ppm, which generally represents the continuation of the present level of protection, and 0.08 ppm, an increased level of protection. Based upon its review, EPA is proposing the 0.08 ppm standard to provide increased protection for children and asthmatics. The EPA also solicits comment on retaining the current primary standard and on an alternative 8-hour standard at a level of 0.07 ppm. 3. In addition, EPA proposes to change the test for attainment (i.e., the form) of the new standard. Currently, the test of attainment is whether a site exceeds the 1-hour standard on an average of no more than once per year, averaged over three years. Given the natural variation in hourly O<INF>3 levels, this ``one expected exceedance'' test can result in relatively unstable attainment/nonattainment designations. The CASAC recommended a change to a more stable form; consistent with this recommendation, EPA proposes a form based on a 3- year average of 8-hour O<INF>3 concentrations. The EPA solicits comment on a range of such concentration-based forms. The EPA proposes to replace the current secondary standard with one of two alternative standards: one set identical to the proposed new primary standard or, alternatively, a new seasonal standard expressed as a sum of hourly O<INF>3 concentrations greater than or equal to 0.06 ppm, cumulated over 12 hours per day during the consecutive 3-month period of maximum concentrations during the O<INF>3 monitoring season, set at a level of 25 ppm-hour. Either of the proposed alternative secondary standards would provide increased protection against O<INF>3- induced effects, such as agricultural crop loss, damage to forests and ecosystems, and visible foliar injury to sensitive species. | 1996-12-13 | 1996 | 12 | https://www.federalregister.gov/documents/1996/12/13/96-30903/national-ambient-air-quality-standards-for-ozone-proposed-decision | https://www.govinfo.gov/content/pkg/FR-1996-12-13/pdf/96-30903.pdf | Environmental Protection Agency | 145 | In accordance with sections 108 and 109 of the Clean Air Act (Act), EPA has reviewed the air quality criteria and national ambient air quality standards (NAAQS) for ozone (O<INF>3) and particulate matter (PM). Based on these reviews, the EPA proposes... |