Attributing Airborne Fungal Spore Increases to Wildfire in Southern California, USA

While warm, dry, and windy weather promotes their dispersal year-round, wildfires are an emerging and significant source of airborne bioaerosols. The intensity of wildfires, the dynamics of smoke plumes, soil disturbance during and after fires, and strong winds can increase the release and long-range transport of microorganisms.

Recent studies show wildfire smoke contains higher concentrations and taxonomic diversity of viable microbes compared to non-smoke air. Understanding how wildfire smoke and wind-driven transport influence bioaerosol levels is critical to explaining the heightened toxicity of wildfire particulate matter. We use a novel two-stage interrupted time series analysis to quantify airborne fungal spore concentrations attributable to multiple wildfires using the Southern California firestorm during October 2007 as a case study.