Why Wildfire Smoke is a Health Concern

Wildfire smoke poses a significant health concern due to its composition and the pollutants it releases into the air. When wildfires occur, vegetation and other organic matter burn, producing smoke that contains a complex mixture of gases and fine particles, that can have adverse health effects for people both outside and inside buildings.

Here are several reasons why wildfire smoke is a health concern:

Particulate Matter (PM2.5 and PM10)

Smoke contains high levels of fine particles, including PM2.5 (particles with a diameter of 2.5 micrometers or smaller) and PM10 (particles with a diameter of 10 micrometers or smaller). Particulate matter can penetrate deep into the respiratory system, reaching the lungs and potentially entering the bloodstream. Exposure to PM2.5 and PM10 have been associated with several health problems, including asthma, bronchitis and other respiratory symptoms, heart or lung related diseases, leading to hospitalization and emergency room visits.[1]

Toxic Chemicals

Smoke also contains a range of toxic chemicals, including carbon monoxide, formaldehyde, benzene, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs). During wildfire events these chemicals are released as organic matter and structures burn during the fire. Prolonged exposure to these toxic substances can have harmful effects on the respiratory system, cardiovascular system, and overall health.

Irritants and Allergens

Wildfire smoke contains irritants and allergens that can cause eye, nose, and throat irritation, coughing, sneezing, and difficulty breathing. These symptoms can be particularly problematic for individuals with respiratory conditions, allergies, or underlying health issues.

Long-Range Transport

Wildfire smoke can travel long distances, affecting regions far from the actual fire site. This means that even areas not directly impacted by the fire may experience poor air quality and health risks from the smoke. As an example, in June 2023 the smoke from Canadian wildfires travelled across the Atlantic Ocean and reached Europe[2] (roughly 3,500 miles).

Duration and Frequency of Exposure

Wildfires can burn for extended periods, resulting in prolonged exposure to smoke. Additionally, some regions may experience recurring wildfires, leading to repeated exposures over time. Cumulative exposure to wildfire smoke can have cumulative health effects, however there is not a good understanding of the accumulated risks of breathing smoke day after day and in the end, what are the long-term effects of prolonged exposure.[3]

Vulnerable Populations

Certain groups are more susceptible to the health effects of wildfire smoke, including children below 18 years, older adults, pregnant women, individuals with pre-existing respiratory or cardiovascular conditions, and outdoor workers. These populations have a higher risk of experiencing health complications from wildfire smoke.[4]

To protect public health during wildfires, it is essential to monitor air quality, both indoor and outdoor, follow guidance from local authorities, and take appropriate precautions. This may include staying indoors, using air purifiers with HEPA filters, wearing masks designed to filter out particulate matter, and seeking medical attention if experiencing severe symptoms.


Learn how TSI can help protect from wildfire smoke by giving you the data to take quick actions.



More resources:

EPA’s Wildfire smoke resources

Smoke-Ready Toolbox for Wildfires

Copernicus EU programme: free open data from satellite Earth observation