NITROGEN-DIOXIDE AND RESPIRATORY ILLNESSES IN INFANTS

Nitrogen dioxide is an oxidant gas that contaminates outdoor air and i ndoor air in homes with unvented gas appliances. A prospective cohort study was carried out to test the hypothesis that residential exposure to NO2 increases incidence and severity of respiratory illnesses duri ng the first 18 months of life. A cohort of 1,205 healthy infants from homes without smokers was enrolled. The daily occurrence of respirato ry symptoms and illnesses was reported by the mothers every 2 wk. Illn esses with wheezing or wet cough were classified as lower respiratory tract. Indoor NO2 concentrations were serially measured with passive s amplers placed in the subjects' bedrooms. In stratified analyses, illn ess incidence rates did not consistently increase with exposure to NO2 or stove type. In multivariate analyses that adjusted for potential c onfounding factors, odds ratios were not significantly elevated for cu rrent or lagged NO2 exposures, or stove type. Illness duration, a meas ure of illness severity, was not associated with NO2 exposure. The fin dings can be extended to homes with gas stoves in regions of the Unite d States where the outdoor air is not heavily polluted by NO2.