The federal Clean Air Act and State regulations continue to pursue emission reductions from natural gas industry sources. In addition, federal greenhouse gas (GHG) requirements are being developed. This annual session on air regulatory issues will cover the status, content, and potential impact of recently proposed and final U.S. EPA air pollutant and GHG regulations affecting gas industry sources. Key state actions will also be discussed. The air quality issues will be summarized and implementation issues will be discussed. Highlights will include key regulatory developments from the last year, including the requirements and status of the March 2009 EPA proposal to revise the National Emission Standards for Hazardous Air Pollutants (NESHAP) for gas-fired reciprocating internal combustion (IC) engines. The proposed rule is scheduled to be finalized in early 2010 and would require emission controls for many existing engines, with NSCR required for rich burn engines and an oxidation catalyst required for lean burn engines. Implementation issues associated with the 2008 federal New Source Performance Standard (NSPS), which established federal standards for NOx, CO and VOC emissions for new gas-fired IC engines, will also be discussed. In addition, the National Ambient Air Quality Standard (NAAQS) for ozone was lowered in March 2008 and EPA is reconsidering the fine particulate (PM2.5) NAAQS based on recent challenges. NOx emissions are regulated as a precursor to both ozone and PM2.5, and potential implications will be discussed, including the status of regional programs that may require geographically broader NOx controls for existing IC engines or turbines. The session will also provide an update on GHG emission issues and regulations. A federal GHG reporting rule has been proposed and additional GHG legislation is under consideration. Federal activity will be reviewed and the relationship of federal actions to state and regional GHG programs will be discussed.