Impacts of Fine Particulate Matter from Wildfire Smoke on Respiratory
and Cardiovascular Health in California
Abstract
Increasing wildfire activity across the Western US poses a significant
public health threat. While there is evidence that wildfire smoke is
detrimental for respiratory health, the impacts on cardiovascular health
remain unclear. This study evaluates the association between fine
particulate matter (PM2.5) from wildfire smoke and cardiorespiratory
hospital visits in California during the 2004-2009 wildfire seasons. We
estimate daily mean wildfire-specific PM2.5 with GEOS-Chem, a global
three-dimensional model of atmospheric chemistry, with wildfire
emissions from the Global Fire Emissions Database (GFED3). We defined a
“smoke event day” as cumulative 0-1-day lag wildfire-specific
PM2.5>= 98th percentile of cumulative 0-1 lag day wildfire
PM2.5. Associations between exposure and outcomes are estimated using
negative binomial regression. Results indicate that smoke event days are
associated with a 3.3% (95% CI: [0.4%,6.3%]) increase in visits
for all respiratory diseases and a 10.3% (95% CI: [2.3%,19.0%])
increase for asthma specifically. Stratifying by age, we found the
largest effect for asthma among children ages 0-5y. We observed no
significant association between exposure and overall cardiovascular
disease, but stratified analyses revealed increases in visits for all
cardiovascular, ischemic heart disease, and heart failure among
non-Hispanic white individuals and those older than 65y. Further, we
found significant interaction between smoke event days and daily
temperature for all cardiovascular disease visits, suggesting that days
with high wildfire PM2.5 and high temperatures may pose greater disease
risk. These results suggest increases in adverse outcomes from wildfire
smoke exposure and indicate the need for improved prevention and
adaptations to protect vulnerable populations.