Wildfires – the burning of large amounts of forest and vegetation – cause substantial increases in airborne particles and gaseous air pollutants. These include carbon monoxide, formaldehyde and PM2.5. Large wildfires can even lead to air pollution travelling thousands of square kilometres. Prolonged exposure to wildfire smoke can cause respiratory and cardiovascular health problems. Learn how wildfires affect air quality, and how to protect yourself from wildfires here.