To better understand the increasing burden on public health from seasonal wild fire smoke, we sat down with environment health researcher Angela Yao of the BC Centre for Disease Control.
Why are there so many forest fires in BC?
Well, about 70 percent of BC is covered by forest. BC has forest fires every year, but recently they’ve become more frequent and intense. And certainly, climate change is having an impact. The average temperature is going up. Winters are generally warmer, and this can lead to more fires for a number of reasons. One example is that warmer temperatures allow insects such as the mountain pine beetle to thrive. The pine beetle infestation has destroyed pine forests in BC and left dead trees behind. These stands are highly flammable if they are hit by lightning or an unextinguished cigarette butt. We know that forest fire frequency and intensity have accelerated since the infestation.
What do we know about forest fire smoke and its health impacts?
We don’t know everything, but we do know that forest fires emit a lot of smoke, which is made up of fine particles that can be breathed deep into the lungs. Inhalation of fine particles can pose serious health risks in the short-term and long term, especially for those who are most susceptible: people with chronic respiratory and heart diseases, infants, pregnant women, children, and older people.
What are some of the greatest challenges in addressing these health impacts?
They are hard to study because forest fire smoke doesn’t last for very long, and it usually affects more rural areas. BC doesn’t have air quality monitoring stations in every community, especially in the rural and remote areas where forest fires are more common. However we can use satellites to measure particulate matter in the atmosphere. And while these measurements don’t give a sense of particulate matter levels on the ground where people live, by combining this information with local weather data, we are getting better information about smoke exposures. The more we know about the exposures, the better we can study their health impacts.
What can public health agencies do to mitigate the health impacts of forest fire smoke?
First and foremost, everyone has to be prepared for smoke episodes. As the climate changes we are going to have more fires and larger fires, meaning more smoke and longer episodes. Individuals and public health agencies need to have clear plans of action for managing smoke exposure when they occur.
We also need to continue improving and expanding our smoke forecasting systems including the Western Canada BlueSky Smoke Forecasting System and FireWork (Canada’s Smoke Prediction System), our provincial air quality monitoring systems, and our public health surveillance systems. We need to use and learn from the information this data provides so that we can better inform and guide the public to avoid risks.
What has the BC Asthma Monitoring System got to do with forest fires?
In 2010, British Columbia had an exceptional forest fire season. The smoke was thicker and the number of communities affected was greater than in previous years. That fall, the provincial medical health officers asked the BC Centre for Disease Control (BCCDC) to develop a monitoring system to better evaluate forest fire impacts on public health. Consequently, in 2012 we launched the BC Asthma Monitoring System (BCAMS).
What should people do to protect themselves on a smoky day?
Common advice includes staying indoors, and reducing physical activity outdoors when there is a lot of smoke around. (Read about other tips for protecting your health from fire smoke here) This is intended to minimize exposure and inhalation of harmful particulate matter. Sometimes you may hear that it can be useful to use an N95 respirator mask or use an air cleaner. The N95 respirators may be helpful for healthy people who work outdoors and who have the support of their occupational health and safety departments, but we don’t recommend them for the general public. They are challenging to fit properly, and they make it even harder to breathe – that is really not helpful for anyone whose breathing is already compromised. We strongly recommend the use of HEPA or electrostatic air cleaners in a well-insulated room. These units can reduce indoor particulate matter during smoke episodes, and studies they can help to reduce respiratory symptoms.
We’re also suggesting that communities should consider cancelling outdoor events and establishing public clean air shelters in buildings such as libraries and community centers.
Further, we suggest that air filtration systems should be augmented in institutions such as hospitals and senior care homes well in advance of smoke episodes occurring. In some cases, it may be possible to evacuate people to areas with better air quality, but this should be a last resort because it causes a lot of stress and anxiety.
Forest fires and their smoke will always be with us, and the best way to minimize smoke impacts on individual and public health is to be prepared. The best offense truly is a good defense.
Angela Yao is an Environmental Health Scientist for the BC Centre for Disease Control, and a PhD student UBC School of Population and Public Health. Her research is focused on assessing forest fire smoke exposure and its public health effects, as well as the development of a public health surveillance system.