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. In the Interior, communities experienced two smoky periods, each lasting several days. The first began in late July and the second in early August.
The highest measured daily mean fine particulate matter in the province occurred in Williams Lake, with a peak of 258 ug/m3 on 19 August, more than 20 times normal background levels. Since forest fire smoke travels long distances, populations throughout the province were exposed.
Forest fire smoke contains a mixture of pollutants including fine particulate matter (PM 2.5) and many toxic compounds. Exposure to forest fire smoke has well-documented health effects, including asthma exacerbations and other respiratory complaints. This summer, British Columbia was smoky enough to observe these effects.
Indeed, MSP billings for physician visits for COPD and asthma increased following smoky days. The proportional increase in visits is most pronounced for regions where particulate matter was highest, like Cariboo-Chilcotin Health Service Area (Williams Lake) (Figure 1). After almost a week of smoky days in Cariboo-Chilcotin, starting in mid-August, the daily number of visits increased by 100% (four visits) above the 10-year mean.
An increase in visits was also observed during the same period in the Fraser North Health Service Area, which includes New Westminster, Burnaby, and Coquitlam, even though PM 2.5 reached only 17.6 ug/m3 (Figure 2). Although the proportional increase in visits above the 10-year mean was lower in Fraser North (14%), the increase in the number of visits was greater (15 visits, Figure 2).
This increase in visits following smoky days was consistently observed in smokier regions (data not shown). While this is only a first glimpse at the data, it does illustrate an important principle in the relationship between air pollution and health: a small increase in exposure in large populations (Fraser North, population 597659) can affect larger numbers of people than a large increase in exposures in small populations (Cariboo-Chilcotin, population 26646).
The evidence we present from this season serves as a reminder that forest fire smoke affects people all over the province, even those distant from the fires. Physicians and public health practitioners across BC can (and did) work together to reduce the health effects of exposure to forest fires, particularly among those most at risk: firefighters, young children, the elderly, and those with chronic respiratory disease.
Physicians play a key role in ensuring that patients with chronic respiratory conditions such as COPD and asthma have rescue medication and emergency response plans, and know when to seek medical help. Public health responses include issuing air quality health advisories, establishing air shelters, and evacuating those at risk during severe smoke events. Partnerships between physicians and public health practitioners become particularly advantageous when novel scenarios arise, such as how to manage patients in hospitals when the indoor air becomes smoky.
Forest fires are the norm in British Columbia, and we can anticipate that they will increase with global climate change. Physicians and public health practitioners must continue to work together to reduce the health impacts of forest fires.
Thank you to Population Health Surveillance and Epidemiology, BC Ministry of Healthy Living and Sport, the Office of the Provincial Health Officer, and Sarah Henderson, environmental health scientist, BC Centre for Disease Control.
This article has not been peer reviewed.
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3. Moore D, Copes R, Fisk R, et al. Population health effects of air quality changes due to forest fires in British Columbia in 2003: Estimates from physician-visit billing data. Can J Pub Health 2006;97:105-108.
Dr Elliott is a federal field epidemiologist in Environmental Health Services at the BCCDC. Dr Kosatsky is the medical director of Environmental Health Services at the BCCDC.
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