Atmos. Chem. Phys. 17, 9223–9236 (2017)

Credit: Eeris Fritz/EyeEm/Getty Images

Smoke from wildfires is an important source of air pollution, posing a substantial risk to human health due to high emissions of fine particulate matter (PM2.5). In many locations, the frequency and extent of wildfires — and thereby PM2.5 emissions — is anticipated to increase with human-induced warming, threatening the mitigation potential of air quality policies which aim to reduce anthropogenic emissions. Using vegetation–fire and chemical transport model simulations, Wolfgang Knorr from Lund University, Sweden, and colleagues investigate whether changing wildfire emissions impact the feasibility of meeting World Health Organisation (WHO) air quality targets.

In most regions of the globe, they find that stringent efforts to curtail anthropogenic emissions will be able to constrain pollution levels to those suggested by the WHO (10 μg m−3), regardless of future changes in wildfires. During the fire season, however, these changes can have a discernible impact, pushing PM2.5 concentrations above critical health-relevant thresholds even under rigorous anthropogenic reduction scenarios. This is particularly true in regions such as sub-Saharan Africa and South-East Asia, despite projections of decreasing population growth. Thus, future wildfire activity represents a significant hazard to regional human health.