Science & Tech

Burnett listed the main outdoor sources of air pollution are from industries and automobiles. Photo: Alex Rivette/Fulcrum
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Tell me how I’m supposed to breathe with no air

As awareness grows as to the societal consequences associated with climate change, there is an ever-growing field of research on the specific consequences of exposure to pollution of the air we breathe.

Dr. Rick Burnett is a University of Ottawa professor and long-time researcher for Canada Public Health, who has been working in the field of air pollution research for the last 30 years. This had led him to compile international data in a paper titled “Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter.”

What previous research has been done?

Burnett has been involved in a lot of the major air pollution studies since the 1990s. Early research was limited to one site, meaning the United States or Canada. In studies like the 1993 ‘Six Cities’ study, research was expanded to assess the consequences of poorer air quality in other countries around the world. Researchers, along with Burnett, were especially worried about the long-term consequences of air pollution on life expectancy in countries like India or China, where there is an observably increased amount of smog. 

To study the consequences of air pollution, researchers use cohort studies, where they interview participants for lifestyle details, then follow the participants through their lives to determine if their death or other health problems are associated with the quality of air where they live.

According to Burnett, all of the research to this date has concluded that “if you live in a neighbourhood or a community with higher pollution, you don’t live as long as if you lived in a neighbourhood or a community with lower pollution.” 

Air pollution research quantifies air pollution as the concentration of fine particulate matter per cubic metre of air. 

For reference, normal concentration levels in Ottawa are between 6 and 8 µg/m3 (micrograms per metre cubed). Burnett explained that Canada has some of the lowest concentration levels in the world because of our large landmass and low population density. The Canadian figure is minuscule compared to air pollution in India and China, where concentration levels are as high as 150 µg/m3.

What inspired this study and its methodology?

As interest in international studies on air pollution grew, Burnett had the idea to study the effects of other types of exposure to particulate matter besides greater air pollution. The study combined the effects of outdoor air pollution with exposure from smoking, second-hand smoke, and burning wood or other matter inside the home (the latter was restricted to developing countries).

Burnett explained that these other factors are significant because smoking a single cigarette is the equivalent of spending 24 hours in a room where the particulate matter concentration is around 700 µg/m3. In developing countries, where wood or dung is burned for heating and cooking purposes, individuals are inhaling “hundreds or thousands of micrograms per metre cubed.”

The study combined sources from outdoor pollution and smoke generated within households to create the Integrated Exposure Response (IER) model, as well as the Global Exposure Mortality Model (GEMM), which only used outdoor air pollution in its calculations.

The study focuses on air pollution-associated deaths, what were the findings? 

Burnett created a computer program that allowed him to compile data from his connections around the world into an international cohort that could be analyzed in one framework.

The results of the study found that, around the world, there are 8 million excess deaths per year that are related to the air we breathe. These findings allowed the director general of the World Health Organization (WHO), Dr. Tedros Adhanom, to conclude that air pollution is “the new tobacco” soon after the paper was published. 

Burnett explained that smoking is also the cause of eight million deaths per year. He drew the comparison that if all of the smokers in the world stopped smoking, it would have the same effect as everywhere in the world having the same particulate concentration levels as we have here in Canada. 

What can governments and industries do to reduce air pollution?

When it comes to policy decisions, air pollution ranks pretty high up on Canada’s priority list. Provinces and the federal government are consistently making efforts to improve air quality for Canadians, including negotiating with the United States about their air pollution. Their concentration levels are slightly higher than ours — they are also is the main source of air pollution for the region that covers Southern Ontario and Southern Quebec. 

Burnett listed the main outdoor sources of air pollution are from industries and automobiles — although the latter are the most recent target of attempts to make technology “cleaner.” Indoor sources are usually things that individuals can control, like burning candles, smoking, and burning wood inside.

We made a big jump in the 1990s towards cleaner technology that reduces emissions of particulate matter, but Burnett said, “the cleaner we go, the harder it is for technology to do the entire job.” We used to be able to “hope that engineers will solve the problem for us” by creating cleaner technology. However, Burnett stated we’ve reached a point where we might also see the effects of individual efforts to reduce air pollution.

That doesn’t mean that the decisions of governments and corporations don’t matter, though, policy on air pollution is still largely based on cost-benefit analyses that decide which options will have the most public health and economic benefits.