Effects of 0.75ppm Sulfur Dioxide on Pulmonary Function Parameters of Normal Human Subjects

Abstract

Of 31 young, healthy male volunteers who participated in this study, 15 were exposed to air (control) and 16 to 0.75 ppm (2.15 mg/m³) SO₂ for 2 hr at 21°C and 60% relative humidity. At the end of the first hour, the subjects exercised for 15 min on a treadmill at 6.4 kmph, with a 10% grade. Methods employed in evaluation of pulmonary function included body plethysmography, spirometry, and multigas rebreathing test. From the battery of 15 pulmonary function parameters, only the pattern of airway resistance changes was significantly altered by SO₂ exposure, although spirometric parameters followed a similar pattern. Eight of the SO₂-exposed subjects, with one or more positive allergen skin tests, appeared to be significantly more reactive to SO₂ than skin test-negative subjects. All subjects remained asymptomatic. The small number of changes observed appeared to be reversible and do not suggest a significant health hazard to normal human subjects exposed to SO₂ under these conditions.