Ontario has made progress towards improving air quality and the health of its residents, while lowering its carbon footprint. Ontarians can breathe easier as air pollutants that contribute to heart and lung diseases have been reduced, and smog days are mostly a thing of the past.
The key factor to our cleaner, greener electricity grid was the closure of Ontario’s coal-fired plants. Besides, having a clean grid has set Ontario up for a prosperous shift towards a low-carbon economy.
Ontario’s next challenge is to reduce fossil fuel use in the transportation sector for a multitude of other benefits.
Improving air quality as smog days decline
For many years, coal-fired electricity generation plants in Ontario emitted pollutants that caused acid rain and smog (the most visible sign of poor air quality), both harmful to human health and the environment. In 2005, 19% of Ontario’s electricity came from coal. This has largely been replaced by conservation, wind and nuclear, with smaller contributions from hydro, gas, and solar.
Once Ontario’s coal plants were closed, emissions of air pollutants from the electricity sector fell sharply between 2005 and 2015 by:
- 82% for nitrogen oxides – which causes respiratory problems by creating ozone at ground level, and acid rain that is harmful to forests and aquatic ecosystems,
- 86% for fine particulate matter – small particles that can cause cancer, heart disease and premature death after being inhaled,
- 99% for sulphur dioxide – which also causes acid rain, and
- 100% for mercury – exposure through the consumption of fish or fish-eating birds and mammals can harm the brain, heart, kidneys, lungs, and immune system.
During the same period, Ontario’s ambient air concentration of three key air pollutants declined by 25% for fine particulate matter, 32% for nitrogen dioxide, and 48% for sulphur dioxide.
Smog days – when smog and air health advisories are issued due to high levels of ozone or other air pollutants – also dropped from 53 days in 2005 to zero in 2017 (see figure below).
Reduced impacts on Ontario’s health system
The importance of clean air to human health is well documented. For example, the Lancet Commission on pollution and health reported that pollution is the largest environmental cause of disease and death in the world today, responsible for an estimated 16% of all deaths.
In 2000, the Ontario Medical Association estimated that air pollution contributed to about 1,900 premature deaths, 9,807 hospital admissions and about 45,000 emergency room visits in Ontario. Most of these impacts can be attributed to the inhalation of particulate matter.
Between 2004 and 2014, the estimated number of premature deaths due to air pollution in Toronto (from all sources) fell by about 23% (to 1,300 per year). Hospitalizations also fell by about 40% (to 3,550 per year). All this, in spite of population growth.
In 2017, only a fraction (4%) of Ontario’s electricity supply came from air-polluting, fossil-fuelled generation: natural gas plants. Ontario’s natural gas plants emit a lower amount of air pollutants than coal, and are mainly used to meet a few hours of daily peak demand (i.e., typically before and after people leave and come home from work).
Health impacts of Ontario’s energy use now
Today, Ontario’s electricity system produces almost no air pollution or GHG emissions – a result of Ontario’s coal phase-out and parallel commitments to conservation, renewables and other lower-carbon sources of electricity. This has dramatically improved the health of Ontarians, and creates the foundation to transition away from using energy sources that contribute to air pollution to using a cleaner, less-polluting one
With the closure of the coal plants, transportation is now the most significant (and growing) source of air pollution and GHG emissions in the province. Switching cars, freight and transit from gasoline and diesel to Ontario’s low-carbon electricity grid is the next public health opportunity. Aside from fuel switching, additional health benefits can be achieved with more sustainable transportation solutions, such as mixed-use neighbourhoods that encourage walking and cycling.
The long-term impacts of cleaner air are being felt today, and more benefits can be achieved should Ontario continue on this path of clean energy.
Learn more about how Ontario’s electricity generation mix has changed (Q4), and how our electricity choices have improved health conditions (Q12) in Making Connections, our 2018 Energy Conservation Progress Report.