UC San Diego

The last several consecutive fire seasons on the West coast, specifically in California, have been the worst in recorded history. These massive fires have been driven largely in part by the anthropogenically caused climate crisis. As the climate crisis worsens, the fire season will as well. This has massive implications for human health as air pollution from each fire can cause disease and hospitalizations. Wildfires are a large source of particulate matter that is less than 2.5 microns in diameter (PM2.5). PM2.5 has been known to cause extremely severe respiratory and cardiovascular issues. Recently, studies have shown that PM2.5 generated by wildfires could have a different and more potent toxicity than PM2.5 generated from other pollutant sources. This project studied the impact of PM2.5 on hospitalizations for respiratory diseases in California between 2006-2013, through a health impact assessment (HIA). We quantified the burden of respiratory hospitalizations related to PM2.5 exposure among California communities through two different approaches: (i) naïve (considering the same toxicity for all PM2.5) and (ii) nuanced (considering the higher toxicity of PM2.5 due to wildfires). The results of the HIA displayed higher attributable numbers of respiratory hospitalizations when accounting for the larger health burden wildfire PM2.5 (i.e., nuanced approach). The delta between the naïve and nuanced approach was higher in northern California. By not considering the differential toxicity of wildfire PM2.5, we underestimate the attributable number of respiratory hospitalizations in California related to PM2.5 exposure. This study can be useful for future air pollution guideline recommendations.