Short-term effects of air pollution on wheeze in asthmatic children in Fresno, California.
Level 3 - non-randomized controlled study
Prospective longitudinal panel cohort study
PubMed 20570778 · doi:10.1289/ehp.0901292
What was done
Researchers followed a cohort of 315 asthmatic children aged 6–11 years in Fresno, California. At baseline, children underwent skin-prick testing for allergens and completed a respiratory symptom questionnaire. Participants completed 14-day panel assessments three times per year, reporting symptoms twice daily. Ambient air pollutant levels (PM2.5, PM10-2.5, elemental carbon, NO2, nitrate, and O3) were assigned based on a central ambient monitoring station to evaluate associations with acute wheezing episodes.
What was found
Across the overall cohort, wheeze was significantly associated with short-term exposure to NO2 (odds ratio [OR] = 1.10 per 8.7-ppb increase; 95% CI, 1.02–1.20) and coarse particulate matter (PM10-2.5; OR = 1.11 per 14.7-μg/m³ increase; 95% CI, 1.01–1.22). Associations for both pollutants were stronger among children sensitized to cat or common fungi on skin-prick tests, as well as among boys with mild intermittent asthma. Numerical estimates were not reported in the abstract for PM2.5, elemental carbon, nitrate, or O3.
Why it matters
The findings identify specific ambient pollutants—traffic-related NO2 and coarse particulate matter—as short-term triggers for wheezing in pediatric asthma. They highlight that children with specific atopic profiles or mild intermittent asthma may experience higher susceptibility to air pollution.
Limits
Exposure was estimated using a single central monitoring station rather than personal or residential air monitoring, introducing potential exposure misclassification. The study was conducted in a single geographic area (Fresno, California), potentially limiting generalizability to regions with different pollutant mixes or climates. Numerical risk estimates and null findings were omitted in the abstract for several evaluated pollutants.
Cited by
- supports Studies show that children living in high-pollution areas such as Fresno, California, have a significantly higher incidence of allergies and asthma.