Part I: Health Outcomes Jonathan M. Samet, William L. Lambert, Betty J. Skipper, Alice H. Cushing, William C. Hunt, Stephen A. Young, Leroy C. McLaren, Margo Schwab, and John D. Spengler
Part II: Assessment of Exposure to Nitrogen Dioxide William E. Lambert, Jonathan M. Samet, William C. Hunt, Betty J. Skipper, Margo Schwab, and John D. Spengler
Nitrogen dioxide is a ubiquitous air pollutant resulting from the combustion of fossil fuels. Indoor levels of nitrogen dioxide are often higher than outdoor concentrations, especially in homes where there are unvented heating and cooking appliances that utilize natural gas, kerosene, coal, or wood. Such exposures are of concern because some studies suggest that children exposed to nitrogen dioxide have more respiratory illnesses than those who are not exposed. When inhaled at high levels, it reacts with and damages lung cells, including those cells that fight infection. Drs. Jonathan M. Samet, John D. Spengler, and colleagues conducted a prospective investigation of 1,205 healthy infants living in homes with gas or electric stoves in Albuquerque, NM. Nitrogen dioxide exposures were carefully estimated from repeated measurements in multiple locations in the subjects' homes throughout the entire 18-month observation period. Respiratory illnesses were monitored prospectively using a surveillance system based on daily parental diaries of respiratory signs and symptoms. Parental reports of illness episodes were validated in a subset of the population by comparison with clinical diagnoses and microbiological testing. Potential confounding factors that influence respiratory infections were reduced by selecting subjects whose parents did not smoke or intend to use day-care services outside the home.