This report describes and documents exhaust emission factors used for compression ignition (CI) engines in the U.S. Environmental Protection Agencys (EPA) final NONROAD2008a emission inventory model. The term compression ignition is synonymous with diesel for the purposes of this report. Pollutants covered include hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), carbon dioxide (CO2), and sulfur dioxide (SO2). Brake specific fuel consumption (BSFC), which is a fuel rate measurement, is also discussed. All PM emissions are assumed to be smaller than 10 microns (PM10) and 97% of the PM is assumed to be smaller than 2.5 microns (PM2.5). The NONROAD Reporting Utility allows the user to select which of these two size ranges is reported. Relative to the previous April 2004 version of this report, this version has been updated to include the Tier 3 standards for recreational marine diesel engines, along with technology name changes for this source category.