What you need to know about wildfire smoke and air pollution
- Wildfire smoke and poor air quality can trigger coughing, wheezing, shortness of breath and irritation of the eyes, nose or throat
People with asthma, COPD, heart disease, and older adults, young children and pregnant individuals, are at higher risk from smoke exposure
During wildfire smoke events, limit outdoor activity, wear a well-fitting mask and seek medical care for severe or worsening symptoms
With wildfire smoke affecting air quality across Toronto in recent years, health experts are warning about the risks associated with exposure to air pollution.
University Health Network (UHN) emergency departments see an increase in patients presenting with respiratory and cardiac symptoms when smoke from wildfires pollutes the air.
However, these visits and potential hospitalizations do not always occur immediately and can continue for several days following periods of poor air quality as symptoms develop.
“At UHN, our emergency medicine teams are seeing firsthand how these environmental events affect patients and communities,” says Dr. Erin O’Connor, Department Head of Emergency Medicine.
Why is wildfire smoke a health concern?
Wildfire smoke is a complex mixture of gases and particles that can affect the respiratory and cardiovascular systems.
One major concern is exposure to PM2.5 — tiny particles that are approximately 30 times smaller than the width of a human hair. Because of their size, they can travel deep into the lungs and, sometimes, enter the bloodstream and contribute to inflammation throughout the body.
Depending on what materials are burning, PM2.5 particles also include gases, such as carbon dioxide, ozone, nitrogen oxides, and volatile organic compounds (VOC) similar to the toxins found in some paints and plastics.
Wildfire smoke can consist of not only burning trees, but also homes and other community structures.
According to Health Canada, PM2.5 is considered one of the primary health risks associated with wildfire smoke exposure. Smoke can affect your health even when concentrations are relatively low, and air quality may be poor even when smoke is not visible or easily detected.
“These particles are difficult to detect because they don’t have a noticeable smell,” says Dr. John Granton, a UHN respirologist. “That can make them particularly dangerous, as people may not realize they’re being exposed and health problems can develop over time.”
What should I do when air quality is poor?
In Canada, air quality is measured in most regions using the Air Quality Health Index (AQHI) — a scale ranging from 1-10+, with 1 to 3 indicating low risk to health and readings over 10 indicating a very high risk to health.
AQHI measures levels of ozone near ground, particulate matter (PM2.5 and PM10) and nitrogen dioxide. During wildfire smoke events, only PM2.5 is used to calculate the AQHI.
The most important step is to reduce your exposure.
"If you can, stay indoors, keep windows closed and avoid strenuous outdoor activity while the air quality is poor," says Dr. O'Connor.
“If you do need to be outside, try to limit the amount of time you spend in smoky conditions.”
People should also wear a well-fitting mask, such as a KN95, for protection.
Those with chronic lung or heart conditions should continue taking their prescribed medications and follow the guidance provided by their health care team.
What symptoms can wildfire smoke and air pollution cause?
Symptoms can vary depending on a person's health, how long they are exposed and the severity of air pollution.
Common symptoms include:
- Coughing
- Wheezing
- Shortness of breath
- Chest tightness
- Irritation of the eyes, nose or throat
Health Canada also notes that wildfire smoke can cause headaches, increased mucus production and sinus irritation. More serious symptoms can include chest pain, severe coughing, dizziness or difficulty breathing.
Who is most vulnerable to smoke and poor air quality?
While anyone can be affected by wildfire smoke, Dr. O’Connor says some groups are at greater risk of experiencing health problems.
These include:
- People with asthma
- People with chronic obstructive pulmonary disease (COPD)
- People with heart disease
- Older adults
- Young children
- Pregnant individuals
People with existing respiratory or cardiovascular conditions may find that smoke worsens their symptoms or triggers flare-ups that require medical attention.
Can wildfire smoke have long-term health effects?
Most people will experience short-term irritation that improves once air quality returns to normal.
However, research suggests repeated or prolonged exposure to wildfire smoke and air pollution may contribute to more serious health problems in the long run.
“Chronic exposure is linked to the development of serious, life-altering cardiac and pulmonary diseases and an increased risk of premature mortality,” says Dr. Granton.
When should I seek medical attention during a wildfire smoke event?
Dr. O'Connor says people should seek medical care if they experience:
- Significant difficulty breathing
- Chest pain
- Confusion
- Severe symptoms
- Symptoms that are rapidly worsening
"Pay attention to how you're feeling, reduce your exposure to the smoke and seek help if your symptoms are severe or getting worse," says Dr. O'Connor.
If you think you are experiencing a medical emergency, call 911 immediately.
As wildfire smoke continues to affect air quality, UHN experts say staying informed and limiting exposure remain the best ways to protect your health.
