A combination of mass balance methods and emission factors based on source data can be used to make comparisons in air pollution potential between different landfill gas (LFG) control or utilization options. This report describes the development of emission factors for controlled primary pollutants (e.g., nonmethane organic compounds) and secondary air pollutants (e.g., carbon monoxide). The following criteria air pollutants and greenhouse gases are addressed in this document: nonmethane organic compounds, carbon monoxide, sulfur dioxide, nitrogen oxides, carbon dioxide, and methane. Data are included that allow an analyst to convert emission factors to units that allow for direct comparison with the energy alternatives mentioned above (e.g., pounds of a pollutant released per kilowatt-hour of electricity produced).