Health effects of wildfire PM2.5 in Latin American cities: A rapid systematic review and comparative synthesis.

Abstract

Introduction: Wildfire activity is intensifying in Latin America due to climate and land-use changes, but the health impacts of wildfire-derived PM2.5 in urban areas remain poorly quantified and recognized.

Objective: To assess the evidence on wildfire-related PM2.5 and its association with mortality and morbidity in Latin American cities.

Materials and methods: We conducted a rapid systematic review and meta-analysis following PRISMA guidelines, using data from PubMed, Scopus, and Bireme. One reviewer independently screened 163 articles and extracted data from 14 eligible studies. A risk of bias assessment was conducted using the Newcastle-Ottawa Scale.

Results: Most studies were conducted in Brazil (n = 12) and used time-series or modelling designs to estimate health risks. Wildfire-specific PM2.5 exposure was associated with allcause, cardiovascular, and respiratory mortality. Reported effect estimates ranged from 1.7 to 7.7% increases in risk per 10 μg/m³ of exposure. Other studies assessed preterm birth, COVID-19 outcomes, and site-specific cancers. While two studies provided harmonized RR estimates for all-cause mortality, high heterogeneity and methodological differences prevented formal meta-analysis.

Conclusion: Wildfire smoke contributes measurably to premature mortality in Latin America, but current evidence is unevenly distributed across regions, time periods, and population subgroups. Studies rarely capture the disproportionate risks faced by indigenous and rural communities or the intraurban disparities linked to poverty and geography. Future research should focus on the health burden of morbidity linked to wildfire PM2.5.