Air pollution and children's asthma-related emergency hospital visits in southeastern France

Children's asthma is multifactorial. Environmental factors like air pollution exposure, meteorological conditions, allergens, and viral infections are strongly implicated. However, place of residence has rarely been investigated in connection with these factors. The primary aim of our study was to measure the impact of particulate matter (PM), assessed close to the children's homes, on asthma-related pediatric emergency hospital visits within the Bouches-du-Rhone area in 2013. In a nested case-control study on 3- to 18-year-old children, each control was randomly matched on the emergency room visit day, regardless of hospital. Each asthmatic child was compared to 15 controls. PM10 and PM2.5, meteorological conditions, pollens, and viral data were linked to ZIP code and analyzed by purpose of emergency visit. A total of 68,897 visits were recorded in children, 1182 concerning asthma. Short-term exposure to PM10 measured near children's homes was associated with excess risk of asthma emergency visits (adjusted odds ratio 1.02 (95% CI 1.01-1.04; p = 0.02)). Male gender, young age, and temperature were other risk factors. Conversely, wind speed was a protective factor. Conclusion: PM10 and certain meteorological conditions near children's homes increased the risk of emergency asthma-related hospital visits in 3- to 18-year-old children in Bouches-du-Rhone.