Environment Minister Catherine McKenna (pictured above) recently reaffirmed the Trudeau government’s commitment to phase-out coal as a power source.

In an interview with CBC News, McKenna once again credited the Ontario coal phase-out with enabling Ontario to have zero smog days, saying “you've seen provinces like Ontario take action and they've gone from 30 smog days or more to nothing, so that's really important.”

But as we have documented previously, this assertion is false—Ontario’s coal phase-out was not a major contributor to the ending of smog days.
In a recent study, we examined whether the removal of coal from the grid in Ontario explains changes in air pollution levels since 2002. We developed statistical models for air pollution concentration in Hamilton, Toronto and Ottawa, looking at monthly average levels of nitrogen oxides (NOx), fine particulate matter (PM2.5) and ground-level ozone (O3), which are all ingredients of smog. As we documented, Ontario’s coal phase-out did not play a major role in ending smog days. In fact, changes in U.S. pollution controls did that:

We find the elimination of coal was associated with a reduction in average urban PM2.5 levels by about 1 to 2 mg/m3 (about 6–12 per cent from the peak levels), but the effect was not statistically significant in Toronto or Hamilton. We find no evidence that the coal phase-out reduced NOx levels, which were instead strongly affected by reduction in U.S. NOx emissions. We find a statistically significant reduction in peak O3 levels from the coal phase-out, offset by a significant increase associated with natural gas plant emissions.

Overall, we conclude that the coal-phase out did not significantly improve air quality, as most of the problem was caused by cross-border emissions from United States. To make the Minister McKenna’s misrepresentation worse, the Ontario government knew eliminating coal would not significantly contribute to emission reductions. In fact, a study by the province in 2005 showed that a majority of local particulates originated from U.S. sources. Another study completed for the province predicted that phasing-out coal would have extremely small effects on urban particulate levels.

The reality is Canada has a strong record of reducing air pollution. But misattributing that progress to particular (highly politicized) government programs such as Ontario’s coal phase-out is misleading, and likely only misinforms energy policy in other jurisdictions.

Minister McKenna should adapt her rhetoric to better match reality when it comes to the phase-out of coal plants in Ontario.