In early 1976, a survey of persistent cough and plegm (PCP) prevalence was conducted in 5623 young adults in four Utah communities. Over the previous five years, community specific mean sulfur dioxide levels had been 11, 18, 36, and 115 micrograms per cubic meter. Corresponding mean suspended sulfate levels had been 5, 7, 8, and 14 micrograms per cu. m. No intercommunity exposure gradient of total suspended particulates or suspended nitrates was observed. In mothers, PCP prevalence among non-smokers was 4.2% in the high-exposure community and about 2.0% in all other communities. In smoking mothers, PCP prevalence was 21.8% in the high-exposure community and about 15.0% elsewhere. In fathers, PCP prevalence among non-smokers was about 8.0% in the high-exposure community and averaged about 3.0% elsewhere. In smoking fathers, PCP prevalence was less strongly associated with sulfur oxide exposure. PCP prevalence rates estimated in a categorical logistic regression model were qualitatively consistent with the prevalences presented above.