Air pollution is a leading cause of disease and death worldwide. We see the short-term consequences of air pollution through health effects such as asthma attacks and shortness of breath, but the long-term effects of air pollution can have an even stronger impact on our health.
As part of the ComPARe Study, I was responsible for assessing the estimated percentage of lung cancer cases in Canada that occur each year due to outdoor air pollution. This task was challenging since air pollution exposures build up over several decades before actually leading to cancer. For our research, we used air pollution exposure models that assessed fine particulate matter (PM2.5) distributions across Canada. PM2.5 is one of the most commonly studied indicators of air pollution and is directly linked to lung cancer.
Using information on the distribution of PM2.5 in Canada and the known relationship between air pollution and lung cancer, we found that about 7% of lung cancer cases in the year 2015 were due to outdoor air pollution – that’s almost 1,700 lung cancer cases. This number is somewhat misleading because it tells us how many cases we could prevent if air pollution was brought down to zero.
We know it’s impossible to eliminate air pollution exposure entirely in Canada. What we can do is introduce and maintain policies and initiatives that can decrease air pollution exposures around the country in coming decades. Global studies of air pollution tell us that other regions of the world have much higher levels of air pollution, but our work shows that there is still much room for improvement here at home. Continuing to invest in transit and green transportation technologies could help us enjoy reduced air pollution, while changes in urban planning such as strategic planting of trees and hedges, and restricting traffic in urban cores, as well as public education can help us reduce higher exposures. If we are able to successfully reduce air pollution exposures by 50% between now and the year 2042, we could prevent 3,700 lung cancer cases in Canada.
Since it takes a long time for air pollution exposures to lead to cancer, even if we reduce exposures by half in future years, it will be several decades before we start seeing the benefits of that reduction. But just because we won’t see the immediate benefits of our efforts to reduce air pollution doesn’t mean we shouldn’t start those efforts now.
Priyanka Gogna, MSc Epidemiology
PhD Epidemiology candidate at Queen’s University
ComPARe Study Environment Node