The National Emissions Inventory (NEI) is a comprehensive and detailed estimate of air emissions of both Criteria and Hazardous air pollutants from all air emissions sources. The NEI is prepared every three years by the USEPA based primarily upon emission estimates and emission model inputs provided by State, Local, and Tribal air agencies for sources in their jurisdictions, and supplemented by data developed by the USEPA. The 2008 NEI was built from emissions data in the Emissions Inventory System (EIS).
U.S. Environmental Protection Agency. 2012a. 2008 National Emissions Inventory Data. Available at: http://www.epa.gov/ttnchie1/net/2008inventory.html. Accessed August 29, 2012.