This webpage is dedicated to state implementation plan (SIP) documents that pertain to every county in the state of Indiana. Other Indiana SIP documents can be accessed and viewed through the Office of Air Quality’s (OAQ’s) Criteria Pollutants webpage. In short, SIPs function for the implementation, maintenance and enforcement of National Ambient Air Quality Standards (NAAQS) as required by Section 110 of the federal Clean Air Act (CAA).

2012 Fine Particles NAAQS

December 28, 2016
June 10, 2016

2010 Sulfur Dioxide (SO2) and Nitrogen Dioxide (NO2) NAAQS

May 22, 2013
January 15, 2013

2008 Lead and Ozone NAAQS

December 12, 2011

2006 Fine Particles NAAQS

October 20, 2009

1997 Ozone and Fine Particles NAAQS

December 7, 2007

Transportation Conformity

Transportation Conformity documents are available on the Transportation Conformity page.