The effects of ambient air pollution on the risk of hospitalisation with acute respiratory illnesses in children: an overview of systematic reviews

Abstract

Background: Children are particularly susceptible to hazardous effects of air pollution, even at low concentrations. Acute respiratory illness is a significant cause of unscheduled healthcare resource utilisation (HRU) in children. Method: An overview of systematic reviews was undertaken. The exposures of interest were particulate matter (PM2.5, PM10), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), carbon monoxide (CO). The primary outcome was the association between these pollutants and unscheduled HRU (hospital admissions, ED visits, or both) for asthma, lower respiratory infection (pneumonia and bronchiolitis), bronchitis, acute wheeze, croup, influenza and pertussis in children. Secondary outcomes were risk of critical care admission, unscheduled primary care visits, and mortality. GRADE methodology was used to determine validity of evidence based on quality of the reviews. Results: Eleven systematic reviews were included. Moderate quality evidence that HRU for asthma exacerbations in children is associated with increased concentrations of all air pollutants studied (PM2.5, PM10, NO2, O3, SO2, CO) was identified. For pneumonia, increased HRU was correlated with increased concentrations of PM2.5, PM10, and O3. For bronchiolitis the quality was low to moderate, and the associations less clear. No studies captured the secondary outcomes. No systematic reviews considered the concentration of the ambient air pollutants in relation to outcomes and WHO concentrations guidelines. Conclusion: Increased concentrations of a range of ambient air pollutants is associated with increased risk of unscheduled HRU for asthma and pneumonia.