This polygon shapefile contains federal one-hour ozone area designations and their classifications as per 40CFR81.305, part of the National Ambient Air Quality Standard (NAAQS) which monitors pollutants in accordance with the Clean Air Act. There are three designation categories: nonattainment, unclassifiable and attainment areas. Non-attainment areas are those which are in violation of the standard. Nonattainment areas have various classifications. Each designation and classification area has an associated date field that represents the "effective" date of the action as published in 40CFR81.305. This data layer is current as of November 2003. Projection: Teale Albers, NAD83This shapefile can be used to identify designation areas for ozone pollution attainment defined pursuant to the corresponding federal National Ambient Air Quality Standard for each pollutant as per the Clean Air Act.