Abstract
In this study, we investigated the impact of wildfires on meteorology and air quality (PM2.5 and O3) over the western United States during the September 2017 period. This is done by using Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to simulate scenarios with wildfires (base case) and without wildfires (sensitivity case). Our analysis performed during the first half of September 2017 (when wildfire activity was more intense) reveals a reduction in modelled daytime average shortwave surface downward radiation especially in locations close to wildfires by up to 50 W m−2, thus resulting in the reduction of the diurnal average surface temperature by up to 0.5 °C and the planetary boundary layer height by up to 50 m. These changes are mainly attributed to aerosol-meteorology feedbacks that affect radiation and clouds. The model results also show mostly enhancements for diurnally averaged cloud optical depth (COD) by up to 10 units in the northern domain due to the wildfire-related air quality. These changes occur mostly in response to aerosol–cloud interactions. Analysis of the impact of wildfires on chemical species shows large changes in daily mean PM2.5 concentrations (exceeding by 200 μg m−3 in locations close to wildfires). The 24 h average surface ozone mixing ratios also increase in response to wildfires by up to 15 ppbv. The results show that the changes in PM2.5 and ozone occur not just due to wildfire emissions directly but also in response to changes in meteorology, indicating the importance of including aerosol-meteorology feedbacks, especially during poor air quality events.
Highlights
Wildfires in North America degrade air quality not just at locations in the vicinity of the fire activity and in remote downwind regions due to long-range transport of smoke plumes [1,2,3,4]
PM2.5 concentrations possibly due to several reasons including uncertainty in wildfire and anthropogenic emissions and due to the fact that the NEI inventory used in this study is representative of the year 2014
We analyze the impact of wildfire emissions on meteorology and air Inover this the study, we analyze theconsidering impact of wildfire emissions on meteorology and air quality western
Summary
Wildfires in North America degrade air quality not just at locations in the vicinity of the fire activity and in remote downwind regions due to long-range transport of smoke plumes [1,2,3,4]. The burned area over the western US is further projected to increase by 54% in 2046–2055 relative to 1996–2005 due to climate change [13] Such an increase in wildfire activity can be expected to enhance impacts on air quality and meteorology in the future. While the adverse impacts of wildfires on air quality and human health have been explored in several studies for both present-day [4,22,23,24,25,26] and future scenarios [27], the role of aerosols, originating from wildfire emissions over the western US, in perturbing meteorology is relatively less explored [28].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
