Particulate matter could be even deadlier than previously thought, recent studies show.
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Health Canada estimates that around 15,000 premature deaths per year are linked to air pollution, including 10,000 from particulate matter.
In Quebec, 4,000 people die prematurely each year from air pollution, including 2,800 from these particles.
“4,000 premature deaths are more than COVID, which claimed around 3,800 lives in Quebec in 2021,” illustrates Johanne Elsener from the organization Santé urbanité.
And while air quality has improved in recent years, “the levels we have are a big problem,” she adds.
1.5 MILLION MORE DEATHS
A study published last September in the journal Sciences Advances shows that mortality from particulate matter is high, even at very low levels (less than 5 μg/m3).
“We found that we underestimated the impact of PM2.5 on mortality by not considering the impact at low concentrations,” said Scott Weichenthal, a McGill University professor and lead author of the study.
This means that there are 1.5 million deaths worldwide every year, in addition to the 4.2 million people from the effects of air pollution.
KNOWN PROBLEMS
Cardiac and respiratory problems related to fine particles are the most documented.
“In high-income countries like Canada, about a third of cardiovascular disease is caused or aggravated by air pollution,” says Ms. Elsener.
“We have not found a concentration at which there is no health risk,” says Dr. Philippe Robert from the CIUSSS de Capitale-Nationale health department. Even at the levels we are seeing in Quebec, there are health implications.
“Most of the effects of air pollution are chronically exposed to low levels for years,” he adds.
The expert agrees that air quality in Canada and Quebec is “better than anywhere else in the world”.
“But even if we say air quality can be good, that doesn’t mean there aren’t health effects,” he continues.
He cites as an example a study conducted on the population of Toronto that estimated that 90% of air quality impacts were due to days when air quality was rated as “good”.
“So if you want to reduce the health effects, you can’t just focus on the worst smog days,” he says.
Fine particles in brief
- Particulate matter (PM2.5) are airborne aerosols and whose diameter is less than 2.5 microns. For comparison: the diameter of a hair is about 50 micrometers.
- They are the main component of smog. Their composition varies depending on the source, season and weather. In Quebec, according to the latest data from 2011, PM2.5 was mainly generated by the Wood heating (43.8%)industry (39.1%) and transport 16%.
- There is no minimum threshold above which particulate matter no longer has any health effects. norms therefore do not protect the population completely.
Harmful health effects
33%
- In a high-income country like Canada, air pollution is associated with this 33% of cardiovascular diseases16% of chronic obstructive pulmonary disease and 8% of respiratory cancer, says Johanne Elsener, citing a report by the Lancet Commission on Pollution and Health.
- Children, the elderly and people with chronic respiratory diseases (e.g. asthma) are particularly vulnerable to the effects of fine particles.
- “There are also studies that are increasingly showing connections with diabetes, premature births and cognitive problems,” adds Dr. Philippe Robert.
- Fine particles are recognized as carcinogens by the International Agency for Research on Cancer.
- The work of Audrey Smargiassi, associate researcher at INSPQ, has even shown links between fine particles and the risk of dementia.
Significant cost to the economy
6%
The direct and indirect costs associated with air pollution are US$30 billion per year in Quebec and US$120 billion per year in Canada. “Corresponding 6% of GDP [du pays]so it’s really important from an economic perspective and not just from a health perspective,” says Johanne Elsener, citing a 2021 Health Canada report.
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