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The Central States Regional Air Planning Association (CENRAP) is researching visibility-related issues for its region and is developing a regional haze plan in response to the US Environmental Protection Agency’s (EPA) mandate to protect visibility in Class I areas. In support of the CENRAP’s need to develop a regional haze plan, Sonoma Technology, Inc.(STI) developed a 2002 ammonia emission inventory for the region in keeping with the emissions estimation techniques presented in Appendix A—Ammonia Emission Estimation Methods for the CENRAP Ammonia Emission Inventory (Methods Document).

Consistent with the Methods Document, ammonia emissions were estimated for 13 source categories using the Carnegie Mellon University (CMU) model and supplemental technical work; 80% of technical work was dedicated to improving emissions estimates for two source categories—livestock production and fertilizer use. For these two categories, as well as biogenic sources, improvements were made to the activity data and/or emission factors used by the CMU model. For four other source categories (industrial point sources, landfills, ammonia refrigeration, and non-road mobile sources), emissions estimates were prepared independently of the CMU model, and for the remaining six source categories (publicly owned treatment works, wildfires, domestic animals, wild animals, human respiration, and on-road mobile sources), emissions estimates were derived by running the CMU model with no alterations.