Outdoor air pollution and the burden of childhood asthma across Europe
Khreis H, Cirach M, Mueller N, et al.
Eur Respir J. 2019;54:1802194
Asthma is a chronic disorder of the airways that effects more than 334 million people worldwide and is often cited as the most prevalent chronic disease in children. A recent systematic review and meta-analysis has suggested that air pollution may contribute significantly towards the development of asthma. The present study estimated the number of new asthma diagnoses across 18 countries that could be attributable to common air pollutants. These included black carbon (BC), nitrogen dioxide , particulate matter ≤2.5 µm in diameter () and particulate matter ≤10 µm in diameter (PM10).
The incident rates of children from 16 EU countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Lithuania, Netherlands, Portugal, Spain, Sweden and the UK) and 2 non-EU countries (Norway and Switzerland) were modelled onto areas of . Similarly, the average annual childhood exposures to NO2, PM2.5 and BC were mapped onto areas of using a validated hybrid LUR model. The LUR model uses information about land-use, geographic and traffic to explain spatial variations in air pollution. Two exposure reduction scenarios were tested: a) the values recommended by the annual World Health Organisation (WHO) air quality guideline and b) the minimum air pollution levels from 41 studies in the underlying meta-analysis.
It was estimated that compliance with the and WHO guidelines would prevent 2434 (0.4%) and 66 567 (11%) of new asthma diagnoses, respectively. Furthermore, reaching the minimum air pollution levels for (1.5 µg), (0.4 µg) and BC (0.4 × ) was estimated to prevent 135 257 (23%), 191 883 (33%) and 89 191 (15%) cases of asthma, respectively.
This study offers the most complete picture of the amount of incident childhood asthma attributable to 3 common air pollutants and suggests that the current NO2 air quality guideline provides less protection than the PM2.5 guideline. There is no evidence that further reductions would not reduce incidence rates further. Therefore, both guidelines may require reductions to promote children’s health.