Air pollutants, bronchial hyperreactivity, and exercise.

The interaction of air pollutants and their effect on bronchial hyperreactivity show that sulfur dioxide and ozone both increase bronchial hyperreactivity. Sulfur dioxide concentrates as low as 0.5 ppm and ozone concentrations as low as 0.2 ppm have demonstrated this effect. Exercise with either sulfur dioxide or ozone exposure can significantly increase bronchial hyperreactivity in susceptible individuals. Other factors including ambient air temperature, time of day, wind velocity and direction, geography, climate, tobacco smoke exposure, and other indoor air pollutants may enhance the impact of air pollutants, causing bronchial hyperreactivity.