An investigation of the impact of Canadian wildfires on US air quality using model, satellite, and ground measurements
<p>Canadian wildfires transport large concentrations of particulate matter into the US, leading to various effects on the surface temperature, the radiation balance, and visibility and exacerbating pollution-related respiratory conditions. Using a combination of surface, satellite, and numeric...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-06-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/25/5497/2025/acp-25-5497-2025.pdf |
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| Summary: | <p>Canadian wildfires transport large concentrations of particulate matter into the US, leading to various effects on the surface temperature, the radiation balance, and visibility and exacerbating pollution-related respiratory conditions. Using a combination of surface, satellite, and numerical models, this study quantifies the increase in surface fine particulate matter (<span class="inline-formula">PM<sub>2.5</sub></span>) in the continental US due to long-range transported smoke from Canadian wildfires during a wildfire episode from 9–25 August 2018. As a widely used indicator of surface pollution levels, satellite-retrieved aerosol optical depth (AOD) can provide crucial information on columnar pollution mass. However, the daily spatial coverage of satellite AOD is restricted due to cloud cover. In order to quantify the daily changes in surface pollution, we fill in the AOD gaps by utilizing simulated 10 <span class="inline-formula">km</span> spatial resolution AOD from a chemistry transport model (CTM). Meteorological variables influencing smoke transport were also integrated alongside the gap-filled AOD product to estimate surface <span class="inline-formula">PM<sub>2.5</sub></span> using geographically weighted regression (GWR) and random forest (RF) models. The model with better performance was subsequently applied to quantify <span class="inline-formula">PM<sub>2.5</sub></span> changes due to Canadian wildfires. To isolate the impact of Canadian wildfires, we calculate the surface <span class="inline-formula">PM<sub>2.5</sub></span> ratio with and without Canadian fire sources by conducting two CTM simulations: one with Canadian wildfire emissions enabled and another with these emissions turned off. Our results show that Canadian wildfires caused a significant increase in surface <span class="inline-formula">PM<sub>2.5</sub></span>, contributing up to 28 <span class="inline-formula">µg m<sup>−3</sup></span> (a 69 <span class="inline-formula">%</span> increase) across different US Environmental Protection Agency (EPA) regions during the August 2018 wildfire event.</p> |
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| ISSN: | 1680-7316 1680-7324 |