PERSONAL EXPOSURES TO ACID AEROSOLS AND AMMONIA

Indoor, outdoor, and personal acid aerosol monitoring was performed for 24 children living in Uniontown, PA, during summer 1990. These measurements were used to investigate the magnitude of personal acid aerosol exposures and its relationship to indoor and outdoor concentrations. Indoor, outdoor, and personal measurements were compared to outdoor measurements collected from a centrally located, stationary ambient monitoring site. Personal exposures reached a maximum of 300 nmol.m-3 for both sulfate and aerosol strong acidity (12-h daytime measurements). Personal exposures were lower than corresponding outdoor levels and higher than indoor levels, with differences being greater for aerosol strong acidity. Air conditioning was found to be an important predictor of indoor sulfate and aerosol strong acidity, while ammonia was found to influence indoor and personal aerosol strong acidity concentrations. Time/activity weighted models of indoor and outdoor concentrations were used to predict personal sulfate and aerosol strong acidity exposures. These models predicted personal sulfate and aerosol strong acidity exposures substantially better than outdoor concentrations alone. The aerosol acidity model, however, was unable to explain all the variability in personal exposures. Research should be conducted to determine the effects of particle loss and ammonia neutralization around the human body.