Impact of boreal wildfires on air quality: from regional to hemisphericscales

International audienceWildfires are a significant source of atmospheric pollutants, including greenhouse gases andaerosols. Among the emitted species, most have long enough lifetimes to be transported overthousands of kilometres. Boreal wildfires are particularly intense and have been shown tostrongly influence the interannual variability of several atmospheric pollutants (carbonmonoxide, CO, and aerosols) in the remote Northern Hemisphere. With a fire risk increasingand fire seasons lengthening as a result of climate change, it is all the more critical to betterestimate the large-scale impact from these large events.Here, the impact of boreal fires on regional air quality in Canada and in Europe (after longrangetransport) is estimated using a combination of satellite data analysis (IASI for CO,MODIS AOD and CALIOP lidar profiles for aerosols) and modelling with the CHIMEREregional chemistry-transport model. The fire emissions are calculated using the APIFLAMEemission model, including in particular a better representation of the potential burning of theground organic layer. Their variability will first be described for the time period 2013-2015.The performance of the model to simulate the local pollution levels and the influence fromlong-range transport (in the mid and high latitudes) will be discussed, focusing on the summerof 2013. The chemical evolution of the main plumes will then be evaluated using observationsof more reactive trace gases (NH3 from IASI, NO2 from GOME-2)