Based on the Environmental Protection Agency's (EPA's) review of the air quality criteria and the national ambient air quality standards (NAAQS) for particulate matter (PM), the Administrator has reached final decisions on the primary and secondary PM NAAQS. With regard to the primary standards meant to protect against fine particle exposures (i.e., annual and 24-hour PM<INF>2.5</INF> standards), the primary standard meant to protect against coarse particle exposures (i.e., 24-hour PM<INF>10</INF> standard), and the secondary PM<INF>2.5</INF> and PM<INF>10</INF> standards, the EPA is retaining the current standards, without revision.