The Health Effects of Wildfire Smoke—and How to Reduce Your Risk

Wildfires are increasingly becoming a fact of life, destroying forests, homes, and anything in their path. But they also pose a different kind of public health threat. Wildfire smoke contains acids, toxic chemicals, metals, and other harmful substances, collectively known as particulate matter, or particulate pollution.

Particulate matter is microscopic. It’s inhaled when you breathe and gets into your lungs or even the bloodstream. It causes symptoms including cough, headaches, shortness of breath, increased heart rate, and more. 

Although particulate matter aggravates preexisting conditions, such as asthma and heart disease, wildfire smoke does not discriminate. Inhaling it may increase the risk of heart attack and stroke, even if you’re otherwise healthy.  The Canadian wildfires of spring 2023 led to a 17% spike in asthma-related hospital visits across the U.S.

Columbia pulmonologist Aliva De, MD, saw an increase in the number of children experiencing cough and respiratory symptoms during June 2023 at a time of year when usual seasonal allergy-related symptoms start to wane.

“The unexpected and quick deterioration of the air quality was a surprise for both patients and providers. It invoked panic and uncertainty,” says Dr. De. “There were several phone calls from concerned parents seeking advice on how to protect their children.”

Dr. De explains the health risks of wildfire smoke, who is most vulnerable, and how to reduce your exposure.

What are the risks of breathing in wildfire smoke if you are healthy?

For otherwise healthy people, exposure to wildfire smoke can lead to stinging eyes, congested sinuses, difficulty breathing, headaches, and coughing, as well as an increased risk of heart attack, stroke, and damage to vital organs.

We need more studies to determine the long-term effects of wildfire smoke exposure in healthy people.

If you are sick or have a chronic health condition, what are the risks of inhaling wildfire smoke?

Wildfire smoke inhalation is particularly dangerous for children, older adults, pregnant women, and anyone with pre-existing respiratory and cardiac diseases, particularly, asthma and chronic obstructive pulmonary disease (COPD). Smoke and particle pollution can trigger asthma attacks and cause heart attacks or strokes in vulnerable populations.

Why are children more susceptible to smoke and bad air quality?

Children have smaller-sized airways and respiratory tracts that can more easily constrict in response to smoke and lead to coughing and wheezing.

Will wildfires cause more asthma in the future?

Yes. More wildfires can definitely cause increased asthma.

A major component of wildlife smoke is particulate matter. Studies have connected particulate matter with an increased incidence of asthma. The effects are particularly worse for people living in densely populated urban areas.

Why is particulate matter dangerous to the lungs (and overall health)?

Particulate matter comprises ultrafine-sized particles containing a mixture of solid and liquid droplets suspended in the air. They are often produced by combustion-related activities such as wildfires.

Given their minute size, particulate matter can evade the normal respiratory system barriers, penetrate deep into the lungs, and damage the alveolar cells in the lungs, as well as trigger toxic reactions and inflammatory processes.

These reactions lead to an increase in respiratory illnesses such as asthma, bronchitis, and colds, as well as reduced lung function. They also increase other cardiopulmonary diseases and promote carcinogenesis (when normal cells turn into cancerous ones), which could potentially be fatal.

What should you do if you or your loved ones are exposed to wildfire smoke?

In addition to following recommendations by local officials, we generally advise a few things:

• Stay indoors as much as possible during bad air quality days
• Use an air cleaner with a filter to keep the indoor air clean
• Use tested and approved respirator masks when outdoors to minimize smoke inhalation
• After smoke exposure, wash off all exposed surfaces with clean water
• If there is nasal congestion or sinus irritation, using saline nasal irrigation can clean the nasal passages of smoke particles
• If you have asthma, rescue inhalers can be used pre-emptively

When should someone seek medical help when wildfire smoke is in the air?

There are a couple of really important things to remember in a situation with a lot of wildfire smoke.

• If you have asthma, be prepared to increase your rescue inhalers during times of bad air quality. Call your doctor or other healthcare provider for advice if symptoms persist or worsen.
• If you or someone else is experiencing respiratory distress—such as shortness of breath or wheezing—call 9-1-1. Urgent care is necessary.

Aliva De, MD, is a pediatric pulmonologist at Columbia.