Mortality associated with wildfire smoke exposure in Washington state, 2006-2017: a case-crossover study

Area of Science:

• Environmental Health
• Epidemiology
• Public Health

Background:

• Wildfire events are increasing in the western US.
• Research on wildfire smoke exposure and mortality risk shows mixed results.
• Understanding the health impacts of wildfire smoke is crucial for public health preparedness.

Purpose of the Study:

• To investigate the association between wildfire smoke exposure and non-traumatic mortality in Washington State.
• To quantify the increased risk of mortality linked to wildfire smoke exposure.
• To inform risk communication and decision-making during wildfire events.

Main Methods:

• A case-crossover study design was employed in Washington State from 2006-2017.
• Wildfire smoke days were identified based on daily average PM2.5 concentrations.
• Conditional logistic regression and time-stratified referent sampling were used, controlling for humidex.

Main Results:

• Same-day wildfire smoke exposure was associated with a 1.0% increase in non-traumatic mortality odds.
• Previous day's exposure showed a 2.0% increase in mortality odds.
• Significant increases in respiratory (9.0%) and COPD (14.0%) mortality odds were observed with same-day exposure, with a notable 35.0% increase in respiratory mortality for adults aged 45-64.

Conclusions:

• Wildfire smoke exposure is linked to increased mortality odds in the days following exposure.
• This study provides the first evidence for this association in Washington State.
• Findings will aid in developing effective risk communication strategies for future wildfire smoke events.