The effect of wildfire smoke on children's health: A systematic review

With wildfires increasing globally due to climate change, children may be more behaviourally exposed and more physiologically vulnerable to adverse health outcomes.

To complete a comprehensive investigation of epidemiological studies examining respiratory and non-respiratory impacts of wildfires to identify research gaps and inform decision-making to protect children's health.

The databases searched were PubMed, Embase, Scopus and Google Scholar.

Global epidemiological studies that investigated individuals under the age of 18 and were published from January 2006 to July 2024 were eligible to be included. Studies were included if they had wildfire days, smoke, or pollutants as the main exposure and had an outcome related to children's health. Though a meta-analysis was not possible, results were reported qualitatively through summaries of evidence tables and noteworthy results and the magnitude of the associations for each outcome was reported.

Twenty-four studies were selected. Sixteen studies examined respiratory outcomes and 11 studies included non-respiratory outcomes. A meta-analysis was not conducted, and consistent conclusions could not be made due to the heterogeneity and the small number of studies. Most respiratory-related studies found positive associations between wildfire exposure and adverse respiratory outcomes. All non-respiratory outcomes, except physical activity, had positive associations with wildfire exposure. For most non-respiratory outcomes, only one study evaluated each outcome. Higher-risk children were asthmatic, obese, under the age of five, in low-income countries or with a low socio-economic status.

There is consistent evidence that wildfire exposure is associated with adverse respiratory health in children, globally. There is less consistent evidence for the effect of wildfire exposure on non-respiratory outcomes. Further long-term research on non-respiratory outcomes in children, specifically physical activity, academic success and mental health is needed, especially in high-risk populations.