Background Emerging evidence suggests that air pollution may contribute to childhood asthma development. We estimated the burden of incident childhood asthma that may be attributable to outdoor NO2, PM2.5 and black carbon (BC) in Europe. Methods We combined country-level childhood incidence rates and pooled exposure-response functions with children's (1–14 years) counts, and exposure estimates at 1 540 386 1 km×1 km cells, across 18 European countries and 63 442 419 children. Annual average pollutant concentrations were obtained from a validated and harmonised European land-use regression (LUR) model. We investigated two exposure reduction scenarios. For the first, we used recommended annual World Health Organization (WHO) air quality guideline values. For the second, we used the minimum air pollution levels recorded across 41 studies in the underlying meta-analysis. Results NO2 ranged from 1.4 to 70.0 µg·m−3, with a mean of 11.8 µg·m−3. PM2.5 ranged from 2.0 to 41.1 µg·m−3, with a mean of 11.6 µg·m−3. BC ranged from 0.003 to 3.7×10−5m−1, with a mean of 1.0×10−5m−1. Compliance with the NO2 and PM2.5 WHO guidelines, respectively, was estimated to prevent 2434 (0.4%) and 66 567 (11%) incident cases. Meeting the minimum air pollution levels for NO2 (1.5 µg·m−3), PM2.5 (0.4 µg·m−3) and BC (0.4×10−5m−1), respectively, was estimated to prevent 135 257 (23%), 191 883 (33%) and 89 191 (15%) incident cases. Conclusions A significant proportion of childhood asthma cases may be attributable to outdoor air pollution, and these cases could be prevented. Our estimates underline an urgent need to reduce children's exposure to air pollution. Footnotes This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article. Conflict of interest: Dr. Khreis has nothing to disclose. Conflict of interest: Dr. Cirach Pradas has nothing to disclose. Conflict of interest: Dr. Mueller has nothing to disclose. Conflict of interest: Dr. de Hoogh has nothing to disclose. Conflict of interest: Dr. Hoek has nothing to disclose. Conflict of interest: Dr. Nieuwenhuijsen has nothing to disclose. Conflict of interest: Dr. Rojas-Rueda has nothing to disclose.
Nearly 67,000 new cases of childhood asthma, across 18 European countries, could be prevented annual if particulate pollution was cut to levels recommended by the World Health Organisation (WHO), according to new research. The WHO states that levels of fine particulate matter PM2.5, released by sources including road vehicles, should not exceed an annually average of 10 µg/m3. Earlier this year, another study estimated that 4 million new cases of asthma across the world among those aged between one and 18 annual were caused by levels of nitrogen dioxide in the air.