The Environmental Protection Agency (EPA) is updating a portion of the Outer Continental Shelf (OCS) Air Regulations. Requirements applying to OCS sources located within 25 miles of states' seaward boundaries must be updated periodically to remain consistent with the requirements of the corresponding onshore area (COA), as mandated by the Clean Air Act. The portion of the OCS air regulations that is being updated pertains to the requirements for OCS sources for which Massachusetts is the designated COA.

The Environmental Protection Agency (EPA or ``Agency'') is determining that the Imperial County nonattainment area would have attained the 2015 ozone national ambient air quality standard (NAAQS) by the August 3, 2021 ``Marginal'' area attainment date, but for emissions emanating from outside the United States.

The Environmental Protection Agency (EPA or Agency) is finalizing three types of actions the Clean Air Act (CAA or Act) related to 28 areas classified as ``Marginal'' for the 2015 ozone National Ambient Air Quality Standards (NAAQS). First, the Agency is determining that five Marginal areas attained the standards by the August 3, 2021, applicable attainment date. Second, the Agency is granting a 1-year attainment date extension for the Uinta Basin, Utah (UT), nonattainment area.

The Environmental Protection Agency (EPA) is taking final action to find that the State of California has failed to submit State Implementation Plan (SIP) revisions to satisfy the contingency measures requirements of the Clean Air Act (CAA) for the 2008 8-hour ozone National Ambient Air Quality Standards (NAAQS or ``standards'') for both the Riverside County (Coachella Valley), California (``Coachella Valley'') and Los Angeles-San Bernardino Counties (West Mojave Desert), California (``West Mojave Desert'') nonattainment areas.