Nonattainment Area - 8 hr Ozone (2015 Standard)

The Nonattainment Area - 8 hr ozone (2015) dataset was updated on November 30, 2025 by the Environmental Protection Agency (EPA) and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics (BTS) National Transportation Atlas Database (NTAD). This dataset provides detailed information about areas identified in the U.S. where ground-level ozone have not met the National Ambient Air Quality Standards (NAAQS) established in 2015 for ground-level ozone and have been designated "nonattainment areas (NAA)". These data are weekly from an OAQPS internal database. However, that does not necessarily mean the data have changed. For more information about this non-attainment area, please see the website https://www.epa.gov/green-book/green-book-8-hour-ozone-2015-area-information. A data dictionary, or other source of attribute information, is accessible at https://doi.org/10.21949/1529061