Health effects of daily indoor nitrogen dioxide exposure in people with asthma

Household gas appliances produce nitrogen dioxide (NO2), which may be assoc iated with an increase in symptoms in asthmatics. The relationship between indoor NO2 exposure, and respiratory symptoms in people,vith asthma was eva luated. Self-reported asthmatics (n=125) wore lapel badges that measured NO2 daily over 6 weeks at home. Outdoor pollutants, spores and meteorological paramet ers were measured daily, in addition to smoking status and demographic fact ors. Seven asthma symptoms were recorded in diaries, for analysis by same d ay and also with 1 day lag exposures, using a generalized estimating equati on. Significant interactions were demonstrated between NO2 at age less than or equal to 14 yrs, with respect to the symptoms of chest tightness on the sam e day (odds ratio (OR): 1.29, 95% confidence interval (CI): 1.16-1.43) and with a 1 day lag (OR: 1.29, 95% CT: 1.14-1.46), breathlessness on exertion with a 1 day lag (OR: 1.13, 95% CI: 1.00-1.28), daytime asthma attacks on t he same day (OR: 1.13, 95% CI: 1.02-1.26) night asthma attacks on the same day (OR: 1.16, 95% CI:1.03-1.30) and with a 1 day lag (OR: 1.15, 95% CI; 1. 03-1.29) after adjustment for potential confounders. A significant interact ion between NO2 and age 35-49 yrs was demonstrated for coughs with a 1 day tag (OR: 1.15, 95% CI: 1.01-1.31). Daily personal exposures to NO2 are associated with asthmatic symptoms in c hildren.