Studies on Air Pollution: Effects of Nitrogen Dioxide on Airway Caliber and Reactivity in Asmatic Subjects; Effects of Nitrogen Dioxide on Lung Lymphocytes and Macrophage Products in Healthy Subjects; Nasal and Bronchial Effects of Sulfur Dioxide in Asthmatic Subjects

摘要

The investigators performed three studies of the effects of NO sub 2 and SO sub 2 on airway function in human subjects. In 9 exercising asthmatic subjects, a 30 min exposure to 0.3 ppm nitrogen dioxide did not alter specific airway resistance, maximal expiratory flow, or the slope of phase III on the single breath test of nitrogen distribution and had no effect on airway hyperresponsiveness to sulfur dioxide. In the second study, repeated exposure of 5 healthy subjects to nitrogen dioxide was associated neither with any significant change in pulmonary function nor in the levels of secretory product of lung macrophages in bronchoalveolar lavage fluid. Analysis of the numbers and types of lymphocytes in venous blood and bronchoalveolar lavage fluid revealed no change apart from a small, possibly artifactual increase in natural killer cells in bronchoalveolar lavage fluid after NO sub 2 exposure. The third study examined whether brief exposures to moderately high concentrations of SO sub 2 caused acute increases in nasal symptoms and nasal resistance in 8 subjects with a history of both asthma and allergic rhinitis and with demonstrable bronchial hyperreactivity to SO sub 2.