From the staff report:
Toronto Public Health (TPH) retained Golder Associates Ltd. to conduct a Health Impact Assessment (HIA), which examined the potential health implications of the BBTCA’s current operations as well as potential expansion to include jets. Highlights of the findings are described below, and will also be addressed independently in a report from the Medical Officer of Health to the Board of Health meeting on December 9, 2013.
The HIA found that the central waterfront population is already exposed to elevated health risks from air pollution, noise, and traffic that originate from many sources, including the airport:
Current levels of air pollutants exceed health benchmarks and contribute to the overall existing burden of respiratory, cardiovascular, and cancer-related illness in Toronto. The BBTCA including related traffic contributes 10-15% of air pollution for people closest to the airport, with the balance originating from non-airport traffic, small industrial and commercial sources, home furnaces, and air pollution from other parts of Ontario and United States.
In the absence of BBTCA, noise levels would already exceed health guidelines which have been established to prevent annoyance, sleep disturbance and impaired children's learning performance in most locations considered, mainly as a result of traffic in the area. The HIA suggests that BBTCA noise increases some adverse effects by up to 12% in some locations.
Current traffic conditions around the airport increase the risk of injuries especially for vulnerable pedestrians including children. Traffic congestion hampers access to recreational, health, and community services in the area, which provide a health benefit to people who use them.
The airport is an important contributor to these risks, based on the HIA of current operations compared with a baseline of no airport.
The HIA also indicates that the airport is currently affecting health by diminishing the quality of local parks, community character, and cultural events. As well, the airport contributes to climate change and introduces risks of aircraft accidents and spills or explosions from fuels and other chemicals in a densely populated area.
It is well established that some groups of people are more vulnerable to health risks than others, including groups with lower incomes, children and seniors, and those with underlying medical conditions such as pre-existing respiratory illness. An examination of the TPH Ward Health Profiles for this diverse and evolving area showed that, compared to the Toronto average, their residents are more likely to be living on low income. They may also include a higher proportion of children who are vulnerable in terms of readiness to learn, higher injury rates especially among children, and higher rates of lung and heart disease. The airport may contribute to the existing health burden among vulnerable people living in these areas.
http://www.toronto.ca/legdocs/mmis/2013/ex/bgrd/backgroundfile-64318.pdf