In collaboration with researchers at the University of British Columbia and New York University, Michael Hadley, MD, MPH, Assistant Professor in the Department of Medicine specializing in cardiology at Icahn Mount Sinai and a member of the Institute for Exposomics ressearch, published a comprehensive review of the known impacts of wildfire smoke exposure on cardiovascular health. Their findings support a link between exposure to wildfire smoke and increased risk of stroke and hospitalization and death from cardiovascular problems.
Heart disease today is the leading cause of death for men and women. As wildfire events are projected to increase in size, intensity, and frequency with an estimated 82 million individuals in the United States exposed to wildfire smoke by 2050, this looming heart health crisis requires the development of more effective strategies to prevent or reduce wildfire smoke exposure.
Climate change and the curtailing of prescribed woodland burns has contributed to a five-fold increase in area burned in the US since 1972. Coupled with the expanding wildland-urban interface, this has resulted in a 77% increase in daily population exposure to wildfire smoke in the past twenty years.
Wildfire smoke is a key contributor to global fine particulate matter – or PM2.5, the inhalation of which is harmful to multiple systems in the human body.
Inhalation of PM 2.5 has been shown to impact the cardiovascular system through numerous biological processes including inflammation, impaired microvascular function, platelet activation, hypercoagulability, and decreased heart rate. These, in turn can lead to elevated blood pressure, atherosclerosis, dyslipidemia, insulin resistance, diabetes, gestational diabetes, and obesity. Studies also show that these effects are enhanced with elevated ambient temperatures – with which wildfires often coincide.
Key cardiovascular outcomes attributed to PM2.5 include cardiovascular mortality, acute coronary syndrome, stroke, heart failure, and arrhythmias. Studies show significant increase in mortality and hospitalizations—even in cases of short term exposure to wildfire. Older adults, women, Indigenous, and people of color, as well as low socioeconomic status individuals are most susceptible to wildfire-related cardiovascular health effects.
PM2.5 is also associated with mental health problems including anxiety and depression. In addition, the disruptive effects of wildfires, including evacuations, school relocations, business closures, property loss, reduced outdoor and physical activity, food insecurity, and stress and uncertainty are linked to posttraumatic stress disorder, anxiety, depression, and insomnia.
What can we do?
The effects of wildfire smoke on cardiovascular health at the individual and population levels can be reduced through specific interventions. Health systems have an opportunity and a responsibility to help protect patients from the harmful effects of wildfire smoke.
At the individual level, Hadley and coauthors found several interventions to be most most efficient at reducing smoke exposure during events of wildfires. They emphasize the role of clinicians in educating susceptible patients such as those with cardiovascular disease and other pre-existing conditions about the risks of smoke exposure and the following actions to reduce harm:
- Monitor air quality through resources such as the AirNow Wildfire page which provides information about local fires and PM2.5 levels and action steps to take to reduce exposure based on current air quality. Note that the impacts of air pollutants from wildfires can be felt many miles from the source, so it is important to monitor local air quality regularly regardless of where you live, particularly if you are a member of a susceptible group.
- Manage traditional risk factors by making sure that pre-existing conditions are well managed through medication or therapies annually before the fire season.
- Maintain clean indoor air at home by sealing doors and windows shut and reducing indoor pollution from sources such as stoves, incense, and furnaces. Consider using central air filters and portable air cleaners with HEPA filters.
- Use a well-fitted face mask or personal respirator that filters out PM2.5 such as an N95 or KF94 mask, particularly if you are at higher risk of cardiovascular disease.
- Minimize outdoor activities when air quality is poor. Be prepared for prolonged periods indoors by making sure you have plenty of necessities on hand such as food and medications.
In addition to taking steps to reduce personal exposures to air pollutants from wildfires, clinicians and individuals should advocate for policies and practices that prevent wildfires, reduce air pollution from all sources, and mitigate climate change.