HISTORICAL INFORMATION

In 1979, EPA established a 1-hour ground-level ozone NAAQS (National Ambient Air Quality Standard) of 0.12 parts per million (ppm). An area exceeded the 1-hour ozone standard each time an ambient air quality monitor recorded a 1-hour average ozone concentration above 0.124 ppm.

On November 6, 1991, EPA classified the Birmingham nonattainment area as a marginal nonattainment area for ozone and added Shelby County to the nonattainment area based on 1987-1989 data.  The area was required to attain the 1-hour standard by November 15, 1993.  After the 1993 ozone season, the area had three years of quality assured air monitoring data (1991, 1992 and 1993) which demonstrated that the 1-hour ozone NAAQS was attained, making the nonattainment area eligible for redesignation to attainment. A direct final rule proposing approval of the redesignation request was signed on August 15, 1995, for publication. Prior to publication of the document, a violation of the 1-hour ozone NAAQS occurred on August 18, 1995.  Due to the violation, the proposed direct final rule was recalled.

Exceedances occurred through 1998 and because of these continuing violations, EPA requested that ADEM submit an attainment demonstration SIP (State Implementation Plan) to attain the 1-hour ozone NAAQS. Alabama submitted its final Birmingham attainment demonstration on November 1, 2000. EPA published approval of this revision to the Alabama SIP on November 7, 2001.

Ozone monitoring data collected from 2001-2003 for the Birmingham area demonstrated  compliance with the 1-hour NAAQS for ground-level ozone. On November 19, 2003, the Alabama Department of Environmental Management (ADEM), submitted a request to redesignate the Birmingham nonattainment area to attainment. ADEM also requested that EPA approve a draft SIP revision containing a 10-year maintenance plan for the Birmingham area. On March 12, 2004, EPA approved the redesignation of the Birmingham 1-hour ozone nonattainment area to attainment.

Particulate matter concentrations are measured on an annual and a 24-hour basis.  The EPA reviewed the standards for particulate matter in 2005.  Upon review, the EPA retained the annual PM2.5 standard of 15 µg/m3, and made the decision to revise the 24-hour PM2.5 standard.  The 24-hour PM2.5 standard was reduced from 65 µg/m3 to 35 µg/m3.

Alabama currently has two counties and two partial counties designated as nonattainment for the annual PM2.5 standard.  Jefferson, Shelby, and a small portion of Walker County make up the Birmingham annual PM2.5 nonattainment area.  A small portion of Jackson County was included in the Chattanooga, TN nonattainment area.

EPA’s presumptive boundary for nonattainment designations for the 24-hour standard is the current annual nonattainment area; however, ADEM only recommended to EPA that two counties be designated as nonattainment for the 24-hour PM2.5 standard.  These counties were Jefferson and Etowah, both of which had nonattaining monitors.  ADEM expects EPA to respond to the recommendations in July 2008, with final designations to follow around December 2008.