(a) Based upon EPA's review of the air quality data for the 3-year period 2007 to 2009, EPA determined that the Metropolitan Washington, District of Columbia-Maryland-Virginia (DC-MD-VA) fine particle (PM2.5) nonattainment area attained the 1997 annual PM2.5 National Ambient Air Quality Standard (NAAQS) by the applicable attainment date of April 5, 2010. Therefore, EPA has met the requirement pursuant to CAA section 179(c) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Metropolitan Washington, DC-MD-VA nonattainment area is not subject to the consequences of failing to attain pursuant to section 179(d).

(b) Based upon EPA's review of the air quality data for the 3-year period 2007 to 2009, EPA determined that the Martinsburg-Hagerstown, West Virginia-Maryland (WV-MD) fine particle (PM2.5) nonattainment area attained the 1997 annual PM2.5 National Ambient Air Quality Standard (NAAQS) by the applicable attainment date of April 5, 2010. Therefore, EPA has met the requirement pursuant to CAA section 179(c) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Martinsburg-Hagerstown, WV-MD nonattainment area is not subject to the consequences of failing to attain pursuant to section 179(d).

(c) Based upon EPA's review of the air quality data for the 3-year period 2007 to 2009, Washington, DC-MD-VA moderate nonattainment area has attained the 1997 8-hour ozone NAAQS by the applicable attainment date of June 15, 2010. Therefore, EPA has met the requirement pursuant to CAA section 181(b)(2)(A) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Washington, DC-MD-VA moderate nonattainment area will not be reclassified for failure to attain by its applicable attainment date pursuant to section 181(b)(2)(A).

(d) Based upon EPA's review of the air quality data for the 3-year period 2008 to 2010, EPA determined that Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE 8-hour ozone moderate nonattainment area (the Philadelphia Area) attained the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS) by the applicable attainment date of June 15, 2011. Therefore, EPA has met the requirement pursuant to CAA section 181(b)(2)(A) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Philadelphia Area nonattainment area will not be reclassified for failure to attain by its applicable attainment date under section 181(b)(2)(A).

(e) Based upon EPA's review of the air quality data for the 3-year period 2007 to 2009, EPA determined that the PM2.5 nonattainment area of Baltimore, Maryland attained the 1997 annual PM2.5 NAAQS by the applicable attainment date of April 5, 2010. Therefore, EPA has met the requirement pursuant to CAA section 179(c) to determine, based on the area's air quality as of the attainment date, whether the area attained the NAAQS. EPA has also determined that the PM2.5 nonattainment area of Baltimore, Maryland is not subject to the consequences of failing to attain pursuant to section 179(d).

(f) Based upon EPA's review of the air quality data for the 3-year period 2003 to 2005, EPA determined, as of July 12, 2012, that the Baltimore 1-hour ozone nonattainment area did not attain the 1-hour ozone standard as of its applicable 1-hour ozone attainment date of November 15, 2005.

(g) Based on 2009-2011 complete, quality-assured ozone monitoring data at all monitoring sites in the Baltimore 1-hour ozone nonattainment area, EPA determined, as of July 12, 2012, that the Baltimore 1-hour ozone nonattainment area has attained the 1-hour ozone standard.

(h) EPA has determined, as of May 26, 2015, that based on 2012 to 2014 ambient air quality data, the Baltimore nonattainment area has attained the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.1118, suspends the requirement for this area to submit an attainment demonstration, associated reasonably available control measures, a reasonable further progress plan, contingency measures, and other planning SIPs related to attainment of the standard for as long as this area continues to meet the 1997 8-hour ozone NAAQS.

(i) EPA has determined, as of June 1, 2015, that based on 2012 to 2014 ambient air quality data, the Baltimore nonattainment area has attained the 2008 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.1118, suspends the requirement for this area to submit an attainment demonstration, associated reasonably available control measures, a reasonable further progress plan, contingency measures, and other planning SIPs related to attainment of the standard for as long as this area continues to meet the 2008 8-hour ozone NAAQS.

(j) Based upon EPA's review of the air quality data for the 3-year period 2013 to 2015, Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE marginal ozone nonattainment area has attained the 2008 8-hour ozone national ambient air quality standard (NAAQS) by the applicable attainment date of July 20, 2016. Therefore, EPA has met the requirement pursuant to CAA section 181(b)(2)(A) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Philadelphia-Wilmington-Atlantic City, PA-NJ-MD-DE marginal ozone nonattainment area will not be reclassified for failure to attain by its applicable attainment date pursuant to section 181(b)(2)(A).

(k) Based upon EPA's review of the air quality data for the 3-year period 2013 to 2015, the Washington, DC-MD-VA marginal ozone nonattainment area has attained the 2008 8-hour ozone national ambient air quality standard (NAAQS) by the applicable attainment date of July 20, 2016. Therefore, EPA has met the requirement pursuant to Clean Air Act section 181(b)(2)(A) to determine, based on the area's air quality as of the attainment date, whether the area attained the standard. EPA also determined that the Washington, DC-MD-VA marginal nonattainment area will not be reclassified for failure to attain by its applicable attainment date pursuant to section 181(b)(2)(A).

(l) EPA has determined, as of November 2, 2022, that based on 2019 to 2021 ambient air quality monitoring data and air dispersion modeling, the Anne Arundel-Baltimore County nonattainment area has attained the 2010 1-hour sulfur dioxide NAAQS. This clean data determination suspends the requirement for this area to submit an attainment demonstration, associated reasonably available control measures, a reasonable further progress plan, contingency measures, and other sulfur dioxide NAAQS attainment plan SIP elements for as long as this area continues to meet the 2010 1-hour sulfur dioxide NAAQS.