Nitrogen Oxides

This report describes a study by Dr. Heinrich and colleagues to investigate the effects of exposure to NO₂ and SO₂ or diesel engine exhaust on tumor formation in hamsters. Hamsters were exposed for 6, 10.5, 15, or 18 months to whole diesel exhaust, diesel exhaust without particles, or a mixture of NO₂ and SO₂. Additional groups of animals exposed to each test atmosphere were also injected with 3 or 6 mg of diethylnitrosamine/kg body weight to evaluate any enhancing effect of diethylnitrosamine on exposure-related changes.

This report investigated changes in pulmonary function, as well as the occurrence of symptoms, in potentially susceptible human subpopulations exposed to nitrogen dioxide. Drs. Morrow and Utell exposed healthy individuals and individuals with asthma, chronic obstructive pulmonary disease, and acute respiratory infection to air or 0.3 ppm nitrogen dioxide. The exposure period (four hours per day for five consecutive days) included defined periods of moderate exercise and pulmonary function measurements including spirometry, airway conductance, airway reactivity, and symptoms.

This report investigated the association of occupational exposure to nitrogen oxides with respiratory infections in British coal miners. Dr. Jacobsen and colleagues leveraged data from the Pneumoconiosis Field Research Study, a long-term epidemiological study of British coal miners with information for the years 1953-1978.