The purpose of this study was to measure the acute response of respiratory disease from peak hourly and daily average exposures to nitrogen dioxide alone and in combination with other pollutants. The study population was made up of families with children attending public elementary schools and living in four California South Coast Air Basin study areas: West Los Angeles/Santa Monica, Garden Grove/Westminster, Glendora/Covina, and Upland/Ontario. The role and responsibility of the contractor were to collect all background and health data, to process and assure the quality of the data, and to prepare this report. Families were recruited for participation during the spring and summer months of 1978. Recruitment included face-to-face interviews for the purpose of collecting family background data. Over 3,000 families were interviewed. From these, 1,402 families (about 350 per study area) were selected.