Here's how wildfire smoke exposure can impact your health

As communities battle out-of-control fires in Alberta, Saskatchewan and Manitoba, thousands of residents — including those in surrounding regions — are being exposed to wildfire smoke, increasing their risk for short- and long-term health effects. 

To date, more than 25,000 people have been forced to evacuate from the three provinces. Over two million hectares have burned so far this wildfire season, which typically runs from May to September. 

The smoke plumes are heaviest above northwestern Ontario and central Manitoba, but have also spread into the Upper Midwest in the United States, according to Environment and Climate Change Canada.

Satellite data also shows that smoke has crossed the Atlantic Ocean into parts of Europe, with more to come this week.

Exposure to wildfire smoke — especially if it's heavy and over a long period of time — can cause adverse health effects in anybody, regardless of health status or age. But even mild wildfire exposure can significantly impact at-risk groups, such as people with chronic health conditions, seniors, young children and pregnant women. 

Wildfire smoke is a mixture of gases, water vapour and particles. Of them, fine particles are the biggest health risk. They cannot be seen by the human eye, but are linked to many health issues.

Dr. Angela Yao, a senior scientist at the B.C. Centre for Disease Control's environmental health services, says the most common symptom is irritation. That can mean a runny nose, itchy eyes, a mild cough and headaches. Most symptoms are mild, and last until the air quality improves.

However, "the small particles or gas in the smoke can get really deep into your lungs and cause inflammation," Yao said. That can increase the risk of respiratory infections, like pneumonia.

In more severe cases, exposure can cause shortness of breath, dizziness and heart palpitations, according to the B.C. CDC, which recommends medical attention.

"For people with chronic conditions such as asthma, [chronic pulmonary heart disease], heart disease or diabetes, smoke can exacerbate their conditions," said Yao.

A recent study published by the American Chemical Society's Environment Science & Technology journal examined B.C. wildfire seasons between 2016 to 2019. It found that infants whose mothers were exposed to wildfire smoke during pregnancy were more likely to experience ear infections and lower respiratory infections after they were born. 

Yao said there is "substantial evidence" on adverse birth outcomes, such as lower birth weight, as a result of wildfire smoke exposure. 

Seeking cleaner indoor air is the most important and effective way to protect yourself during a wildfire smoke event, Yao said.

It's also important to keep your doors and windows closed, especially when you're operating air purifiers in your home.