A longitudinal study of indoor nitrogen dioxide levels and respiratory symptoms in inner-city children with asthma

Abstract

Background: The effect of indoor nitrogen dioxide concentrations on asthma morbidity among inner-city preschool children is uncertain. Objectives: Our goal was to estimate the effect of indoor NO2 concentrations on asthma morbidity in an inner-city population while adjusting for other indoor pollutants. Methods: We recruited 150 children (2-6 years of age) with physician-diagnosed asthma from inner-city Baltimore, Maryland. Indoor air was monitored over a 72-hr period in the children's bedrooms at baseline and 3 and 6 months. At each visit, the child's caregiver completed a questionnaire assessing asthma symptoms over the previous 2 weeks and recent health care utilization. Results: Children were 58% male, 91% African American, and 42% from households with annual income