CONTROLLED EXPOSURES OF HUMAN VOLUNTEERS TO SULFATE AEROSOLS - HEALTH-EFFECTS AND AEROSOL CHARACTERIZATION

Abstract

Possible acute adverse health effects of sulfate aerosols were studied through controlled exposures of volunteer human subjects. Both healthy and asthmatic adult men were exposed for 2 h (with intermittent exercise) to ammonium sulfate, ammonium bisulfate and sulfuric acid of particle size distributions and concentrations intended to simulate worst case exposures during Los Angeles [California, USA] smog episodes. Lung function tests were performed by the subjects on entering and before exiting from a carefully controlled environmental chamber. Subject symptoms were evaluated in a standardized manner. Aerosol concentrations and size distributions were determined by an on-line computer/aerometric monitoring system; gravimetric and chemical analyses were performed on impactor and total filter samples after test exposures. Little or no evidence of adverse health effects from 2 h multiple-day exposures to any of the compounds at worst case ambient concentrations was seen.