The report gives results of an estimation of primary sulfate emission factors for use in the 1980 and 1985 National Acid Precipitation Assessment Program (NAPAP) emissions inventories. The estimates were developed from an assessment of existing measurements data for source categories including external combustion, chemical manufacturing, primary metals, wood products, mineral products, and petroleum refining. Initial elements of the assessment summarized primary sulfate formation mechanisms prevalent in combustion processes and reviewed the state-of-the-art methodology for primary sulfate sampling and analysis of source emissions. The Controlled Condensation System (CCS) was evaluated as the best primary sulfate emission measurement approach. CCS-derived measurement data were abstracted from an inventory of reports consisting of a variety of environmental assessment studies, field measurement evaluation experiments, and the U.S./Canadian Work Group 3B inventory. The measurement data were then used to estimate primary sulfate emission factors for the corresponding source categories. Uncertainty estimates are given for each emission factor, and source categories are identified where data are either lacking or incomplete to permit the assignment of an emission factor.

"EPA/600/7-85/037." "September 1985." Microfiche.