Recommended Procedures for Development of Emissions Factors and Use of the WebFIRE Database

This guidance document describes the procedures, data evaluation criteria, and associated tools and data management systems that the U.S. Environmental Protection Agency (EPA) recommends for developing air pollutant emissions factors for stationary emissions units or processes. This document supersedes the previous EPA guidance document for emissions factor development (Procedures for Preparing Emission Factor Documents (EPA-454/R-95-015, November 1997)).
This document presents an introduction to emissions factors and provides the historical background for how and why the EPA has developed emissions factors for stationary emissions units or processes. This document also describes the approach and procedures recommended by the EPA for developing new or revising existing emissions factors.