The report gives results of an evaluation of the effects of fuel and combustion modifications on the formation of primary acid aerosols (used broadly to include all sulfates, nitrates, chlorides, and fluorides in all their forms) and their significance as combustion-generated pollutants from large stationary sources. Primary acid aerosols are emitted directly from a source or formed (primarily by condensation reactants) in the immediate vicinity (0.5 mile); secondary aerosols, formed downstream in the plume, are not considered. Available, rather meager field data were collected and interpreted in view of current knowledge of mechanisms of formation of potential acid aerosols and their precursors. Although sulfates, nitrates, chlorides, and fluorides were considered, based on available data, only sulfates appear to be significant as primary acid aerosols. All of the various combustion modifications for NOx control are expected to have little effect on primary acid aerosol emissions, except perhaps firing with low excess air which has a potential to abate both NOx and acid aerosol emissions. Combustion modifications and fuel changes may lead to an increased formation of small particles which could increase the formation of acid aerosols through heterogeneous reactions. Most effects, however, are speculative due to the meager data available. Information gaps have been identified; further research is indicated.

Prepared by Battelle-Columbus Laboratories, Columbus, Ohio, under Contract no. 68-02-1323, Task no. 49, program element no. EHE624a ... "April 1977." "EPA/600-7-77-041." Includes appendix. Includes bibliographical references (pages 129-139).