The Impact of California's Wildland Fires on Particulate Matter: A Comparison of Measurements and CMAQ Model Estimates from 2008 to 2018

The threat and intensity of wildfires have significantly risen due to climate change and human-related factors. Since the start of the early 2000s fires in the United States (US) have progressively risen in size. In 2020, the average area burned from fires in California were three times larger than average for the continental USA. Estimates from the Community Multiscale Air Quality (CMAQ), a widely used regulatory model by the US Environmental Protection Agency (EPA), have frequently been employed for quantifying the impacts on air quality, public health, and infrastructure. However, there has been limited research conducted to validate the recent results concerning fire emissions. Focusing on California, this study is a continuation of previous work released from the US EPA for wildfire and CMAQ model performance. This study evaluated ten years, 2008 to 2018, of simulated PM_2.5 from CMAQ with two methods: in-situ observations (AQS monitors) and gridded surface PM_2.5 data fusions (in-situ observations and satellite data). Overall, our performance evaluation found that CMAQ performed well with an R² of ~0.40 for simulations with fire. We recommend improvements to the model to better characterize fire emissions to improve future public health analysis. This talk will address the growing need of stakeholders (e.g., model data users) to increase the understanding of how to properly apply model data to research.