Auditory and visual sustained attention during ozone exposure.

Experiments were conducted to determine the effects of different concentrations of ozone at 0.00, 0.25, 0.50, and 0.75 parts/million (ppm) on sustained visual and auditory attention tasks (vigilance performance). When the rate of signals to nonsignals was low, approximately 1 out of 30, ozone in concentrations as high as 0.75 ppm did not alter performance to either visual or auditory tasks. However, when the ratio of signals to non-signals was increased, a deficit in performance beyond that of the normal vigilance decline was observed during the 0.75 ppm ozone exposure. However, no changes in false positive responses occurred. The results were interpreted within the framework of an arousal hypothesis, suggesting that high concentrations of ozone may produce overarousal.