Interaction of Two Air Pollutants, Sulfur Dioxide and Ozone on Lung Functions

摘要

Increased use of high sulfur fuels with consequent potential for increased SO2 levels in the atmosphere has led to renewed interest in the effects of SO2 on man's physiological functions. The effects on young males of 0.4 ppm SO2 and 0.4 ppm ozone alone and in combination under environmental conditions of 25 degrees C and 45% relative humidity were studied. Subjects alternately walked 15 minutes and rested 15 minutes during a two hour exposure. Subjects exposed to filtered air or to 0.4 ppm SO2 showed no significant changes in pulmonary function. When exposed to either ozone or ozone plus SO2, significant decreases in maximum expiratory flow, forced vital capacity, and inspiratory capacity were observed. One subject exhibited enhanced sensitivity to the combination of SO2 and ozone. However, for the greater majority of the subjects, no synergistic effects were discernible. Whether such synergism would become evident during similar or higher ambient levels of the pollutants with higher temperature and relative humidity awaits further investigation.