Published June 10, 2023 at 3:07 p.m.
The wildfires that have raged in Quebec for several weeks are affecting the quality of the air we breathe. But what does this smoke contain and what effects does it have on our organism?
What’s in that smoke?
Smoke from fires consists of carbon monoxide and dioxide, hydrocarbons and nitrogen oxides. The exact composition of wildfire smoke depends on a few important factors: what is burning – grass, brush or trees; the temperature – flame or simple slow combustion; and the distance between the person inhaling the smoke and the fire producing it. Distance affects the smoke’s ability to “age,” meaning to withstand the sun and other chemicals in the air along its path. It can become more toxic with age. It is important to note that large particles, such as ash, generally do not travel very far from the fire, but small particles, or aerosols, can traverse continents.
These small harmful particles are 50 times smaller than a grain of sand and get stuck in our lungs. Their prevalence is one of the reasons health authorities issue air quality warnings using PM 2.5 (particulate matter) as a measure.
New York City hit by Quebec wildfires. Photo: Portal.
A study by the California Air Resources Board, which is responsible for protecting the public from the harmful effects of air pollution, found smoke from the 2018 campfire in Paradise, California had dangerous levels of lead and other metals in the windblown smoke. The metals, which have been linked to adverse health effects such as high blood pressure and adverse effects on development in long-term exposed children, were carried by the wind more than 150 miles, with levels in some areas 50 times higher than average. The results suggest smoke from fires reaching communities may have been even more dangerous than initially thought due to burning building materials.
What consequences for our health?
Short-term exposure can irritate the eyes and throat, while prolonged exposure lasting days or weeks can increase the risk of lung damage and cardiovascular problems.
The human body is equipped with natural defense mechanisms against particles larger than PM2.5. You can tell if you’re coughing up phlegm or blowing your nose after hanging around the campfire. The black or brown mucus found in the tissue is evidence of the existence of these mechanisms.