Assessing the Impact of the 2018 Colorado Wildfires on Carbon Monoxide and the Aerosol Burden

Abstract:

In the summer of 2018, Colorado experienced a record-breaking wildfire season, provoked by the warmest forest temperatures in 124 years, record low precipitation, and spruce beetles expanding their infestation across the state. This study focused on analyzing the air pollutants from wildfires by comparing available ground-based observations, satellite measurements, and simulations from the Community Earth System Model version 2 (CESM2). Specifically, we analyzed Carbon Monoxide (CO), Particulate Matter 2.5 (PM2.5), and Aerosol Optical Depth (AOD) to identify the Colorado 2018 wildfire season. We found a positive correlation between CO, PM2.5, and AOD ground observations. The values of CO, PM2.5, and AOD increased in August and peaked on August 20th with average values of 452.71 ppb, 29.91 μg/m^3 , and 0.64, suggesting possible intensive fire events occurring in August. We utilized The Community Atmosphere Model with Chemistry (CAM-chem) part of the Community Earth System Model (CESM) to investigate the reason for these peak values. We tracked the CO emissions originating only from Colorado, the total CO emissions, and the CO only coming from anthropogenic and background sources. We found that the Colorado wildfire Spring Creek and Bull Draw Fires are responsible for the increase of CO from August 1st to August 14th, while wildfire emissions outside Colorado are responsible for the increase of CO from August 18th to August 31st. The simulated results and satellite and ground measurements show a similar trend, but the modeled values are lower than the observations from August 14th to August 31st, indicating further improvements need to be made regarding wildfire emissions or transport in the model.