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EPA Proposes Revisions to Global Warming Potentials
Wednesday, April 03, 2013
The U.S. Environmental Protection Agency (EPA) is proposing amendments to the global warming potentials (GWP) used to calculate greenhouse gas emissions. GWP is a metric that incorporates both the heat-trapping ability and atmospheric lifetime of each greenhouse gas.

EPA is proposing to make several changes to the GWPs in Table A-1 to Subpart A of 40 CFR 98. The GWP values in Table A-1 are required to be used when calculating GHG emissions for DNR air construction permit and air operating permit applications per the definition of subject to regulation in 567 IAC 22.100 and 33.3(1). EPA is proposing updates to several GWPs to be consistent with the Intergovernmental Panel for Climate Change Fourth Assessment Report. For example, the proposed GWP for methane increases from 21 to 25 and the proposed GWP for nitrous oxide decreases from 310 to 298.

The proposed rule is available at EPA is accepting comments on the rulemaking until May 17, 2013.  For general questions, please contact Marnie Stein at or (515) 281-8468.

This list serve article is intended for consultants, industries, environmental groups, general public, and other entities regulated under the Clean Air Act. It was written by the DNR Air Quality Bureau to share regulatory news, program updates and technical guidance.