The Environmental Protection Agency (EPA) is proposing to determine that the Anne Arundel County and Baltimore County, Maryland sulfur dioxide (SO<INF>2</INF>) nonattainment area has attained the 2010 primary SO<INF>2</INF> national ambient air quality standard (2010 SO<INF>2</INF> NAAQS). In designated nonattainment areas where air quality data demonstrate that the NAAQS have been attained, EPA interprets certain requirements of the Clean Air Act (CAA) as no longer applicable for so long as air quality continues to meet the standard. Under this Clean Data Policy, EPA may issue a determination of attainment, known as a clean data determination (CDD), that a nonattainment area is attaining the relevant NAAQS. If finalized, this proposed CDD would suspend the obligation to submit certain attainment planning requirements for the nonattainment area for as long as the area continues to attain the 2010 SO<INF>2</INF> NAAQS. EPA is also simultaneously proposing to approve certain elements of the attainment plan contained in Maryland's state implementation plan (SIP) revision for the Anne Arundel County and Baltimore County SO<INF>2</INF> nonattainment area (referred to hereafter as the Anne Arundel-Baltimore County Area, or simply the Area), submitted to EPA on January 31, 2020. The requirement to submit the elements that EPA is proposing to approve would not be suspended under this proposed CDD, as set forth in EPA's Clean Data Policy, because EPA considers them to be independent of attaining the NAAQS under the CAA. Finally, EPA is approving as SIP strengthening measures certain emission limit requirements on large SO<INF>2</INF> emission sources that were submitted as part of Maryland's attainment plan for the nonattainment area. This determination of attainment and approval of certain elements and emissions limitations into the SIP does not redesignate the Area to attainment or constitute a full approval of the submitted attainment plan or of a maintenance plan. This action is being taken under the CAA.