Photo: fil photo
The Bennett Bridge was suffocated in forest fire smoke in August 2019
Exposure to air pollution in Canada leads to nearly 8,000 deaths a year, says a new study.
The research, published today in a Health Effects Institute (HEI) report, looked at the mortality of 7.1 million Canadians over the last 25 years.
Long-term exposure to particulate matter (PM2.5) proved to be the most harmful in combination with other pollutants such as ozone. As of 2016, it led to 7,848 deaths a year, though that is probably a lower estimate compared to what Canada is experiencing now.
But even low concentrations of PM2.5 – a pollutant vaulted into the air from forest fires, wood-burning stoves and fossil fuels from cars and trucks – have been shown to help increase the risk of death in people already suffering from cardiovascular disease. – and heart disease, diabetes, pneumonia or a respiratory disease such as COPD.
“There really is no safe level of air pollution,” said the study’s lead author Michael Brauer, a professor at the University of British Columbia’s School of Population and Public Health.
Brauer and his colleagues combined data from satellites, local air sampling, and atmospheric modeling to measure PM2.5 concentrations in Canada from 1981 to 2016.
After analyzing the data, the researchers found that cities had particle concentrations between almost three and eight times higher than in rural areas. Until 1990, the highest PM2.5 concentrations were found in major cities, including Vancouver, Toronto, Hamilton, and Quebec City.
And while these pollution levels dropped in the following years, even low levels were found to increase the risk of premature death.
‘We picked the low-hanging fruit’
Brauer’s data hampers the results of a study released last year in which Health Canada estimated that all forms of air pollution contribute to the early deaths of 15,300 Canadians each year.
In this study, BC’s Interior suffers some of the largest fallout from air pollution in the country.
Between 2013 and 2018, the top 10 census departments in the country with the largest exposure to PM2.5 were all in BC’s interior, according to a 2021 Health Canada analysis of the impact of air pollution on human health.
Of these, half of the census divisions – including Central Kootenay, where Nelson is located – were among the top 10 sections of the country with the highest per capita. inhabitant of premature death.
Brauer said climate change, from rising urban temperatures to devastating wildfires, threatens many of the advances that have taken place in recent decades.
“We picked the low-hanging fruit,” he said. “With a warmer climate, things are unlikely to get better without more aggressive action … And the faster we decarbonize. The faster we will eliminate these health effects.”
The growing impact of bad wildfire seasons has led some physicians to reconsider the way they diagnose health crises. After a record-breaking heat wave and brutal fire season, a doctor from BC even diagnosed a patient suffering from “climate change”.
“A lot of people in Kootenays thought in a way that this would be a good place to hide while the rest of the world falls apart. But of course it hits us here, just like it hits many places, and we really see the effects. , ”Said Dr. Kyle Merritt, director of Kootenay Lake Hospital in Nelson.
The global death rate from air pollution is likely to be much higher
The World Health Organization (WHO) estimates that outdoor air pollution leads to around 4.2 million deaths worldwide each year. Brauer’s research would increase this estimate by a further 1.5 million.
Yet few jurisdictions have air quality standards that reflect the risk Brauer found in his study. Canada’s 2012 Ambient Air Quality Standards pave the way for reducing pollutants in a step-by-step approach until 2025. Current standards recommend PM2.5 concentrations below 8.8 micrograms per day. square meters.
In the United States, national standards are 12 micrograms per square meter.
WHO’s recently updated standards meanwhile lower this threshold to 5 micrograms per liter. square meters.
But none of these pollution limits meet the limit of 2.5 micrograms per day. square meters, in addition to which Brauer says, increases the risk of mortality.
It should be a signal to regulators both in Canada and around the world that air quality standards need to be strengthened, Brauer said.
“Globally, that means we have to get on with it,” he said. “This will be there – even relatively clean countries, Western Europe, North America … there is still significant influence.”
Photo: The contribution
PM2.5 concentrations decreased throughout the study period, but even low exposure levels significantly affected the risk of premature death. Brauer et al. (2022)
The UBC-led study is the latest in a series of HEI-supported studies looking at how even low levels of outdoor air pollution affect human health.
The first, a 2021 study looking at the effects of particulate matter, carbon black, nitrogen dioxide and ozone in 11 European countries, found “significant” correlations between those exposed to low levels of pollution and early mortality in people with heart disease. vascular and respiratory diseases, and lung cancer.
The second report, released earlier this year and focused on the United States, tracked low levels of exposure to air pollution among 68.5 million older Americans. Once again, the story was repeated: even low levels of exposure to particles increase the risk of death.