Respiratory health outcomes of children and adolescents exposed to wildfire smoke: a systematic review

Wildfire events are increasing in frequency and intensity globally, partly due to climate change. This emerging public health crisis will disproportionately impact vulnerable populations such as children. Epidemiological studies link wildfire smoke, especially fine particulate matter (PM2.5 and PM10), with adverse respiratory outcomes; yet few focus specifically on pediatric populations. This systematic review examines wildfire smoke impacts respiratory health in youth populations by analyzing studies identified through a comprehensive literature search in PubMed and Web of Science through 30 September 2024. Of 120 publications identified, five met the inclusion criteria: three retrospective cohorts, one cross-sectional, and one case-crossover study. Studies were conducted in the U.S. and Canada, using various exposure assessment methods including stationary monitors, satellite imagery, and surveys. Not all studies reported compatible effect measures, vote counting based on the direction of effect, and statistical significance was applied. All studies reported increases in respiratory symptoms, hospital visits, and medication use on days with significant wildfire smoke exposure. Differences in exposure measurement methods, health outcome definitions, and age stratifications limited cross-study comparability. Despite limitations, the review found consistent evidence linking wildfire smoke exposure to worsened respiratory health in children. Further research using standardized exposure assessments and age-specific analyses is needed.