The Health Effects of Wildfire Smoke: A Public Health Crisis

A recent southern california wildfire burning extremely close to homes.

The majestic Rocky Mountains, often obscured by thick smoke from wildfires nearby and in other states, threatens the health of millions. Wildfires produce carbon monoxide, nitrogen oxides, methane, and volatile organic compounds (known as particulates) significantly lessen air quality locally and in downwind areas. Fine particles pose the most significant threat to health, causing eye irritation, runny noses, and bronchitis.

Both children and adults are negatively affected. As our climate warms, exposure to wildfire smoke will inevitably increase indefinitely. Smoke exposure increases respiratory and cardiovascular hospitalizations, homelessness, in addition to numerous deaths. Considerable green-house gas emissions from wildfires, in most probability, will hasten climate change.

The relationship between climate change and wildfires

Fires need three ingredients: favorable weather or climate, combustible fuel, and a spark. Climate change creates warmer, drier conditions, especially during droughts with longer fire seasons increasing the wildfire risk. Hotter temperatures evaporate more moisture from the ground, drying out the soil and escalating vegetation flammability. Furthermore, changes in rain and snow patterns and other climate-related changes significantly increase the likelihood of more frequent and intense fires.

Human activity is responsible for most wildfires, with drier and warmer conditions spreading the fires and making them harder to contain. Furthermore, forest management practices allowing for the accumulation of vegetation that becomes fuel, and the growth of houses in risky areas increases wildfire danger.

The physical and mental health risks associated with wildfires

The direct health risks associated with wildfires are numerous, including burns, injuries, dehydration, respiratory complications, heatstroke, mental illness, post-traumatic stress disorder (PTSD), depression, and insomnia.

Wildfire smoke contributes to worsening asthma, obstructive lung diseases (COPD), cardiovascular disease, and other heart conditions. Individuals with these conditions account for more emergency room visits and prescription medicine use.

Firefighters encounter higher levels of direct smoke exposure, increasing their risk of lung cancer and cardiovascular disease-related mortality. Pregnant women, the elderly, the obese, and those with lower socio-economic status (SES) are more vulnerable to the adverse health effects of smoke exposure.

Hypertensive disorders during pregnancy with the risk of early onset of preeclampsia are severe complications due to smoke exposure. Additionally, prematurity and low-birthweight occur due to smoke exposure. Contamination of local drinking water, including Benzine, increases cancer risk as a significant health threat.

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Children, pregnant women, and the elderly are the most vulnerable

The psychological effects of exposure to wildfire smoke can linger for years, often heightening the risk for mental illness in adulthood. Children are more vulnerable to wildfire exposure as they spend more time outdoors, breathe more air relative to their body weight, with a higher number of particles penetrating their lungs due to fewer nasal removal of particles. The toxic exposure to wildfire smoke can further negatively impact respiratory health in adulthood.

Recent research on wildlife exposure among children includes associations with ADHD, autism, school performance, decreased birth weight and height, and an increased prevalence of obesity. Children can suffer from compromised cardiovascular health from particulates in the future.

Behavioral reactions to stress from wildfires include becoming withdrawn, irritability, agitation, and angry outbursts. Children with disabilities suffer from significant psychological anxiety, grief, and loss during wildfires when evacuation is necessary. Disruptions and changes in daily routine, familiarity, and heightened fear require additional support for this population of children.

People 65 years and over are twice as likely to sustain injuries or die during a fire. By age 75, the risk is tripled compared to the general population. At age 85, the risk of injury or death quadruples. Comorbidities among the elderly, including diabetes, COPD, cardiovascular disease, compromised immunity, limited mobility, vision, and hearing loss, increase morbidity and mortality.

Smoke exposure from wildfires exacerbates pre-existing conditions. Medium and dense smoke exposure is associated with a higher risk for myocardial infarctions, ischemic stroke, ischemic heart disease, heart failure, transient ischemic attack, dysrhythmias, pulmonary embolism, and long bone fractures.

Furthermore, elderly black people experience higher smoke exposure compared to their white counterparts. Elderly black people have a higher risk of hospital admissions with respiratory illness. Older women of all races account for increased hospital admissions for respiratory disease.

Populations in substandard living that allow smoke to infiltrate indoors, homelessness, jobs requiring outdoor work, and lack of access to healthcare become more vulnerable to the health risks of wildfire smoke. In California, 90% of the farmworkers are Latino without health insurance and experienced more significant exposure to wildfire smoke in the wine country during the 2020 fires.

Harmful psychological effects

The psychological effects of wildfires create havoc for those living in the western U.S., where most wildfires occur. Domestic violence and substance use increases along with depression and PTSD. The added stress of the COVID-19 pandemic intensifies adverse mental health. COVID-19 may abate with vaccines; however, the risk of future wildfires will continue with the acceleration of climate change.

Sleep disturbances, nightmares, difficulty concentrating, excessive worrying, and absences from work and school disrupt the lives of millions affected by wildfires. Although most people will recover, those predisposed to depression and anxiety will require behavioral health interventions.

According to the Firefighter Behavioral Health Alliance, depression, addiction, anxiety, PTSD, and suicide are common among wildland firefighters. They are more likely to suffer from these conditions than the public.

Directly experiencing the devastation of lost homes, lives, habitat, and land destruction takes a toll on firefighters. The exhaustion and stress from fighting more intense fires affect relationships with an escalation of domestic violence and divorce. Firefighters and their families find adjusting after prolonged periods away challenging, especially when depression, anxiety, and PTSD become evident.

The methods previously used to fight wildfires are no longer working. As a result, many firefighters feel a sense of failure and defeat. Awareness of the need for mental health resources and support for and among firefighters is growing with increased therapy services.

Wildfires lead to homelessness for wildfire victims

Although the term “climate refugee or migrant” is usually reserved for those fleeing from Central America, thousands of Americans experience displacement and disruption due to wildfires. For those who lose their homes to wildfires, homelessness ensues, leading to more significant stress and an exacerbation of physical illness.

Unemployment rates contribute to physical and mental health complications. Many who lose their homes are reluctant to rebuild due to the fear of further fires. The rising cost of housing and lack of affordability, especially in California, leaves many, including retirees on fixed incomes, permanently homeless.

Renters and lower-income property owners without insurance take the most brutal hit. Relocation to other communities or states requires seeking new employment, making new friends, and starting over. For those who are resilient, surviving these changes is possible. However, for many without resilience, their lives remain shattered.

Loss of healthcare providers

Healthcare providers impacted by wildfires become unavailable or unable to work. A shortage of staffing in a local hospital can affect the entire community. The disruption of primary care places an increased burden on emergency departments and hospitals. Pharmacies impacted by the wildfire may not dispense life-sustaining medications, putting those whose lives depend on pharmacies at significant health risks or even death.

Loss of health insurance due to unemployment can result in critical health conditions unattended. As previously mentioned, wildfire smoke exacerbates pre-existing respiratory and cardiovascular conditions resulting in a greater frequency of hospitalizations.

Public health strategies to reduce wildfire smoke exposure

The Centers for Disease Control (CDC), the U.S. Environmental Protection Agency, and local health departments provide guidelines for reducing wildfire smoke exposure through various strategies. These measures include:

  • Stay indoors if possible.
  • Keep windows and doors closed.
  • Create a “clean room” without a fireplace and as few doors and windows as possible (bedroom). Use a portable air cleaner.
  • Reduce the smoke entering the home by setting the HVAC system to recirculate or close the outdoor intake damper.
  • Avoid using an evaporative cooler.
  • For a window air conditioner, close the outdoor air damper and ensure a tight fit between the unit and window.
  • Use a portable air cleaner.
  • Install a high-efficiency furnace or air conditioner filter (Minimum Efficiency Reporting System or MERV 13 rating).
  • Avoid smoking cigarettes, frying or broiling food, using aerosol products, burning candles or incense, using gas, propane, wood-burning stoves, and vacuuming without a HEPA filter.
  • Avoid demanding activities to reduce smoke inhalation.
  • Wear a well-fitted N95 or P100 Respirator.
  • Stock up on food and medications. Purchase food that does not require refrigeration or cooking.
  • Organize essential items in advance, such as financial and personal documents. Be knowledgeable regarding evacuation routes and the nearest evacuation shelter. Prepare your children and pets when creating an evacuation plan.


As climate change escalates, the intensity, duration, and frequency of wildfires will grow. As healthcare professionals, we cannot ignore the devastating impact of climate change on our health and well-being.

The sequelae of wildfires and smoke exposure is a significant public health crisis — harmful physical and psychological effects of wildfires and smoke exposure impact not only those nearby but downstream. Healthcare professionals play an essential role in responding to wildfires’ physical and mental impact and mitigating the human factors contributing to climate change.

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