Abstract
Rats and guinea pigs were exposed to 0.5 ppm O3 , 10 mg/m 3 sulfuric acid (H 2 SO 4 ) mist, or their combination for 6 h/d, 5 d/wk for 6 mo. Microscopic alterations were seen in the lungs of guinea pigs exposed to O 3 alone or in combination with H 2 SO 4 mist. No other microscopic lesions were present in either rats or guinea pigs. No biologically meaningful synergistic effects were noted in animals exposed to the combination of O3 and H 2 SO 4 mist.