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How safe is the air you breathe?

It can be easy to take for granted that the air we breathe is healthy. Dr. Scott Weichenthal, a Research Scientist at Health Canada and Assistant Professor in the Faculty of Medicine at McGill University, is examining the content of the air we breathe in several cities across Canada. His research seeks to understand the short and long-term health effects of exposure to specific types of airborne particles found in air pollution.

Particulate matter is the general term used for a mixture of solid and liquid particles in the air. It includes aerosols, smoke, fumes, dust, ash and pollen. The composition of particulate matter varies with place, season and weather conditions. Fine particulate matter – or PM2.5 – is particulate matter that is 2.5 microns in diameter and less. This air pollutant is a concern for people's health when levels in air are high, since they can easily be absorbed in the lungs and cause health issues. Currently, researchers aren’t able to differentiate between the health effects of individual particles based on their presence in the air, but Scott’s research is looking to change that.

Instead of assuming that all particles in polluted air are equally harmful to health, Scott is scrutinizing the underlying, pollution-induced health effects of specific particles. In the future, this could better inform air pollution regulations and public health measures, which could be tailored to the specific types of particulates found in the air.

“Regulating particle mass concentrations has been a true public health success story and has saved countless lives in Canada and abroad. However, we are reaching a point where we need to have a better understanding of why some particles may be more harmful than others,” explains Scott. “Toxicity varies depending on the composition of the pollutant, and we need to start integrating this information into our assessment.”

In particular, Scott is dedicated to identifying and evaluating environmental risk factors for chronic diseases such as cancer and cardiovascular disease. That is where the oxidative potential of the particles comes in.

“Think of oxidative stress like rusting in your body. Air pollution increases oxidative stress and over time causes cell damage that can lead to a variety of diseases,” says Scott. “We are looking at how airborne particles in different parts of Canada contribute to oxidative stress, to determine how likely they are to cause harm. We have already shown that integrating this information into our health studies provides a clearer picture of how air pollution may contribute to heart and lung problems.”

In order to better target public health interventions and focus his efforts, Scott is also developing visual representations, or air pollution maps, of the areas where the particles are more likely to be harmful. Health Canada is currently studying the air in 40 locations across the country in hopes of developing more efficient ways of regulating particulate matter.

“The approach we are evaluating complements traditional mass-based measurement and eliminates the need to treat all particles the same,” says Scott.

Once completed, this study will allow regulators to be more efficient in calculating health risks and provide a clearer idea of the real health impact of air pollution in Canada.

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