Health impacts of wildfire smoke in the Arctic

Climate change has increased the vulnerability of boreal forests and grasslands to wildfires. An increase in high-latitude wildfires has resulted in the deterioration of air quality, particularly in Western Siberia, where PM_2.5 levels have increased at >1 µg m^-3 year^-1 during 1998−2020. Arctic wildfire carbon emissions have doubled during the last 20 years, and in Siberia they have shifted northwards. Using fire air pollutant emissions data from the Quick Fire Emissions Dataset (QFED), we create two emissions scenarios for Arctic Council member nations, with and without wildfires. PM_2.5 is simulated for the two scenarios using the Community Earth System Model, which we evaluate using in-situ measurement data, finding a large negative bias in wildfire plumes. To correct this underestimation we use a high resolution PM_2.5 reanalysis dataset, improving agreement with observations. Bias-corrected scenarios are used to estimate air quality degradation and resulting health impacts due to Arctic Council nation wildfires across the Northern Hemisphere high- and mid-latitudes for the period 2001-2020. We use the Global Exposure Mortality Model to estimate the health impacts of chronic exposure to Arctic wildfire-attributed PM_2.5­. We find that health impacts are highly variable, with 25,000−55,000 premature deaths yearly, with most of the health burden falling on nations outside the Arctic Council, particularly China, due to transboundary transport of Siberian wildfire PM_2.5. Health impacts have decreased during our study period partly due to the northwards shift in wildfires.