Wildfires are becoming an increasingly large contributor to air pollution across the United States. Wildfire smoke, which contains many harmful air pollutants, can travel great distances from the source fire, affecting people in urban spaces like the Bay Area of California.

In the summer and fall of 2023, there were several fires burning across California, including two large fires in the North: the Smith River Complex Fire and the SRF Lightning Complex Fire. While these fires burned for several months, there was one week in September where the winds blew the smoke into the Bay Area, as shown in the top figure below. Due to the high resolution of BEACO₂N, we can see the smoke plume move its way into the domain in the bottom figure, drifting from the west into the Bay over time.