Cross-State Air Pollution Rule (CSAPR)

In 2011 the U.S. EPA finalized the Cross-State Air Pollution Rule (CSAPR) in response to a 2008 court decision remanding the Clean Air Interstate Rule (CAIR) to EPA. CSAPR requires some states (not including Connecticut) to reduce annual SO2 emissions, annual NOx emissions and/or ozone season NOx emissions to assist in attaining the 1997 ozone and fine particulate matter (PM2.5) and 2006 PM2.5 National Ambient Air Quality Standard (NAAQS). For more information on CSAPR, its successor, the CSAPR Update, and subsequent actions by EPA and states, visit EPA’s Cross-State Air Pollution Rule web page.
Content last updated October 22, 2019