Nitrogen dioxide: ambient exposure in human disorders.

Abstract

Nitrogen dioxide (NO2) is produced in certain industrial processes. Point exposure to high concentration of NO2 (>100 ppm), such as in silo filler's disease and during chemical warfare, produces acute lung injury, and death in the worst cases. Acute exposure to lower concentration of NO2 (0.5-15 ppm) may increase airway responsiveness, especially in patients with obstructive airway diseases. The effects of chronic exposure to ambient NO2 (<0.5 ppm) are much harder to quantify, in part due to the low concentration and the existence of other co-pollutants. Because NO2 is a reactive gas, it remains possible that exposure to ambient concentration of NO2 for a prolonged period of time may result in cellular and biochemical changes that ultimately cause pulmonary dysfunction.