Canada’s dirty air: how pollution is hurting our health
This summer, record numbers of forest fires in Western Canada made air pollution impossible to ignore. Eerie photos of the smoky skies of Vancouver made the news – then disappeared after the air cleared.
But the threat remains. Air pollution contributes to asthma, COPD and cardiovascular disease. And high background levels are often more harmful than dramatic, one-off events like the ones we saw this year.
In Alberta, a new report found that the province’s air quality is poor – in one area, it’s below Health Canada’s acceptable levels. In contrast, Ontario is doing well, with air pollution lower than it has been in decades. What does that mean to the health of Canadians living in those provinces?
The Alberta Air Zones Report
The Alberta Air Zones Report revealed that the Red Deer Zone is failing the national Canadian Ambient Air Quality Standards. Nearly half the rest of the province, including Calgary and Edmonton, are close to the threshold.
The report, which was released in September, measures air quality from 2011 to 2013. Created by Alberta’s Environment and Parks ministry, it found that for fine particulate matter, the Red Deer Zone was above both the annual and daily limits. Four out of five of the other areas in the province were in the warning zone for the annual limit as well.
The province did better on ground level ozone, the other component measured in the report, with most of Alberta in the lower threshold. But small particulate matter, caused mainly by combustion, is the form of air pollution with the greatest impact on health.
What caused the higher levels? “Population and economic growth are a couple of the drivers – sources like industry, transportation and home heating,” says Jason Maloney, a public affairs officer for Alberta Environment and Parks.
A continued reliance on coal fired power is another factor, according to Joe Vipond, an emergency room physician and member of the Canadian Association of Physicians for the Environment.
Dust storms and forest fires also contribute to air pollution. But their impacts are removed from the report since they’re seen as natural, unpreventable events.
Because of the poor results, the Air Quality Standards require that the province create a response plan that outlines how it will improve air quality in the Red Deer zone. The plan is set to be released within the next few weeks.
The health effects of air pollution
Years ago, emergency room physician Brian Rowe was working in Sudbury when girl after girl started coming in, all wheezing. “About 100 patients showed up in the emergency department within an hour,” he says. They eventually realized the cause: “One of the mining companies had released a toxic plume of gas, which went rolling along and landed in a Girl Guides camp.”
That’s an extreme case, but it’s not unusual for air pollution to send patients to the emergency department – a Canadian Medical Association report estimated air pollution was connected to 92,000 emergency department visits in Canada in 2008. Air pollution increases the number of hospitalizations for asthma, stroke and heart failure.
Overall, its largest impact is on lung health. Air pollution raises the risk of pneumonia, COPD and asthma attacks – and may even be a cause of childhood asthma. Children, who spend more time outside and breathe at a faster rate than adults, are particularly vulnerable. It also causes lung cancer: the World Health Organization’s International Agency for Research on Cancer has classified air pollution as carcinogenic, declaring it the most widespread environmental carcinogen and calling out particulate matter as the major cancer-causing agent.
Close behind lung disease are cardiovascular illnesses: poor air quality increases the risk of heart attacks and stroke, especially for smokers. Long-term exposure is strongly associated with various forms of heart disease.
More recently, preeclampsia and pre-term birth have been suggested as other repercussions. And it may also cause a small increase in the risk of diabetes. Researchers are now moving into new territory to determine if air pollution is linked to dementia (which to date has had mixed results), early-onset inflammatory bowel disease and even appendicitis.
All this translates into premature deaths. The CMA estimates air pollution was responsible for 21,000 early deaths in Canada in 2008. Worldwide, fine particulate matter is responsible for 2.9 million deaths, according to the 2013 Global Burden of Disease Study.
The loss in life expectancy can be measured in months. Small particulate matter is responsible for an 8.6 month reduction in life expectancy for the average European, according to the World Health Organization. Similarly, an American study estimated that improvements in fine particulate matter exposure in the 1980s and ’90s led to an average increase in life expectancy of 4.9 months in the 51 metropolitan areas studied.
The effects of air pollution are difficult to study. Many studies use home addresses to map results, and sophisticated land-use regression models help incorporate the effects of buildings, traffic and hills. But that doesn’t take into account some important factors. “You have to make an assumption that the person is being exposed to the air pollution [in their area],” says Gilaad Kaplan, a gastroenterologist and epidemiologist at the University of Calgary. “But people may not be residing or working in these areas, they may be staying indoors – there are so many different things that affect it.”
The future of such research may be small personal air quality monitors, says Kerri Johannson, a respirologist who studies air pollution and lung disease at the University of Calgary. “Currently, air pollution exposure can be very challenging to map to the individual person.”
Nevertheless, the impacts of air pollution are becoming clear. “The science on fine particulate matter is especially robust,” says Vipond. “Whether it’s a particularly bad day or a higher baseline, what you get is increased incidents of heart attacks, strokes, asthma and COPD, and all of this contributes in a very real way to increased mortality.”
As research on fine particulate matter has grown, it has shown everyday air pollution can be more damaging than acute levels. Lower levels also cause more harm than previously thought; in fact, there doesn’t seem to be a floor. “We’re not finding any evidence of a threshold at all,” says Paul Villeneuve, an associate professor at Carleton University and epidemiologist who focuses on the effects of air pollution.
These new studies are what prompted the new regulations in the Canadian Ambient Air Quality Standards Act. The acceptable daily levels of fine particulate matter have been reduced from 30 µg/m³ to 28 µg/m³. A new annual standard, based on the annual average concentrations, of no more than 10 µg/m³ has also been added. That’s close to the World Health Organization’s guidelines, which recommend no more than an annual mean of 10 µg/m³ and a maximum hourly mean of 25 µg/m³ – and much more stringent than the EU’s annual limit of 25 µg/m³.
Ontario’s coal phaseout
Air pollution is a sensitive issue in Alberta: In some ways, it pits the thriving economy against public health. “I understand both sides of that challenge,” says Kaplan. “But I don’t think you need to sacrifice one thing for another.”
He points to Ontario as proof. The province’s Air Quality Report had good news: between 2004 and 2013, the amount of ambient air pollution decreased, including a 30% decrease in fine particulate matter. The entire province now meets the Canadian Ambient Air Quality Standards for fine particulate matter. And the number of smog advisories in 2013 dropped to zero for the first time in 20 years.
A large part of that is because the province has phased out coal power, pushed by concerns about the public health effects of air pollution put forward by groups such as the Ontario Medical Association. Coal has been replaced with natural gas and renewable energy. In 2003, it made up 25% of the energy in the province; the last coal plant closed in 2014.
The transition was made easier by the fact that most of the plants were older, and that Ontario’s coal was imported. (In Alberta, on the other hand, coal is a major industry).
The improvement can’t just be credited to removing coal plants, as the province simultaneously benefited from tighter American pollution laws. (The most current report on transboundary air pollution, from 2005, estimated over half of Ontario’s ground-level ozone and fine particulate matter had blown over from the U.S.)
In Toronto, the cleaner air has reduced the number of premature deaths in which air pollution was a contributing factor, from 1,700 in 2004 to 1,300 in 2014. The number of hospitalizations has also dropped, from 6,000 to 3,550.
“[Ontario is] going down the right path,” says Vipond. “It has contributed in a very real way to decreased mortality and improved public health.”