RESUMO
BACKGROUND: Asthma is a common childhood disease that leads to many missed days of school and parents' work. There are multiple environmental contributors to asthma symptoms and understanding the potential factors inside children's homes is crucial. METHODS: This is a dual cohort study measuring household particulate matter (PM2.5), behaviors, and factors that influence air quality and asthma symptoms in the urban homes of children (ages 6-10) with asthma; one cohort had cigarette smoke exposure in the home (n = 13) and the other did not (n = 22). Exposure data included measurements every 5 minutes for a month. RESULTS: In the entire study population, a large contributor to elevations in indoor PM2.5 above 35 µg/m3 was not using the stove hood when cooking (8.5% higher, CI 3.1-13.9%, p<0.005). Median PM values during cooking times were 0.88 µg/m3 higher than those during non-cooking times (95% CI 0.33-1.42). Mean monthly household PM2.5 level was significantly related to the presence of a cigarette smoker in the home (10.1 µg/m3 higher, 95% CI 5.2-15.1, p<0.001) when controlling for use of the stove hood and proximity to major roadway. There was a trend toward increased odds of persistent asthma with increases in average monthly PM2.5 (OR 1.1, 95% CI 0.97-1.3, p = 0.16). CONCLUSIONS: Consideration of only outdoor PM2.5 may obscure potentially modifiable risks for asthma symptoms. Specifically, this preliminary study suggests that cooking behaviors may contribute to the burden of PM2.5 in the homes of children with asthma and thus to asthma symptoms.