Wildfire Smoke Exposure
January 21, 2020
As we watch the wildfire situation in Australia unfold with heavy hearts, it is a good time to think ahead to spring and summer 2020 here in Canada. According to the Canadian Red Cross, there are roughly 8,000 wildfires in Canada each year. Densely forested areas across much of Canada are at risk of wildfires, particularly during dry conditions. Forest fires can devastate communities, destroy buildings and infrastructure, and even claim human lives. On average in Canada, wildfires burn 2.5 million ha/year, nearly half the size of Nova Scotia.
As we are no strangers to wildfires, and while we have never experienced anything like what is happening in Australia, it is worth re-visiting our own lessons learned. Wildfires not only threaten lives and property locally but also create incidents of extreme air pollution that can negatively affect the health of populations over vast geographic areas.
Wildfire smoke, which generally contains large amounts of respirable particulate matter, can increase the risk of respiratory and cardiovascular diseases. Children, the elderly and those with existing conditions are particularly susceptible. Respirable particulate matter measured in Edmonton and High Level this past summer were 10-30 times higher than the national guideline. This was due to wildfires burning in central and northern Alberta.
Wildfires are often large enough to create their own weather patterns. The heat generated by a large fire can create updrafts sending gasses and combustion by-products/smoke high into the atmosphere creating pyrocumulus clouds. Pyrocumulus clouds are turbulent, fast moving masses that can produce lightening strikes which can start new fires, exacerbating a wildfire situation.
Once combustion by-products/smoke are high in the atmosphere, they can be transported great distances. Image 1 was recently taken in Auckland, New Zealand where the sky appeared orange due to smoke from Australian wildfires 2,100 km away. Image 2 was taken outside of Edmonton, Alberta in May 2019 by one of our engineers on their way to conduct smoke impaction assessments. The image shows reduced air quality and visibility due to smoke originating 250-750 km away from the Slave Lake and High Level wildfires.
During an extreme air pollution episode, it is recommended to stay indoors to reduce exposure to smoke. To limit smoke filled air from entering your home, , set ventilation systems to recirculate, upgrade filters, and consider creating a Clean Air Shelter (CAS) in one of the rooms of your home by using a correctly sized HEPA air filtration system.
If it is necessary to go outdoors during an extreme air pollution episode, it is advised that an N95 or P100 particulate respirator be worn. Click HERE to review an excellent summary from the EPA on how people can help protect themselves if found in such a situation.
