Characterization of OVOC emission from wildfires using observations from Sentinel-5 Precursor

Oxygenated volatile organic compounds (OVOCs) are released to the atmosphere from biogenic, anthropogenic, and pyrogenic sources. The role and importance of OVOCs in ambient atmospheric composition and their role in climate change was established many years ago. Another topical issue is the formation of secondary organic aerosols (SOA), which potentially are relevant for cloud formation, heterogeneous chemistry, and can also contribute to the long-term transport of volatile organic compounds. OVOCs can be detected from space-borne observations using the Differential Optical Absorption Spectroscopy (DOAS) method. Here, measurements from the TROPOMI instrument, which was launched on the Sentinel-5 Precursor (S5P) platform in October 2017, are used. 

During the year 2019, large wildfires occurred in North America, Amazonia, Siberia, and Australia. These fires created elevated amounts of many different gases, e.g. CO, NOx, OVOC, O₃, SO₂, CO, HONO, CH₃CO.O₂.NO₂ (PAN) and other toxic species as well as aerosols affecting air quality. During the transport of plumes from fires, photochemical transformation of emitted species occurs. Overall, polluted air is transported to regions where the plumes are dispersed. For many of the fires, unexpectedly high amounts of OVOCs are detected in plumes as consequence of continued emission and conversion of some OVOCs. The amounts of OVOCs emitted were found to depended on the type of biomass burned and the location of the fires. 

Here, a characterization of OVOC emissions from fires is performed by using OVOC S5P observations, in combination with forward trajectories simulated with the FLEXPART model and proxies of vegetation types, leading to new insights in the emissions of OVOCs from fires.