Ross McKitrick, in his non-climate life, writes from time to time on particulate matter pollution in Ontario. The Toronto Globe and Mail ran a a story a few days ago about Toronto in 1912, showing the picture at left in its print edition. The amount of pollution looks like some present-day images of Chinese cities. It is also a challenge to those who think that pollution in Toronto (or similar cities) is at “unprecedented” levels.
In the late 19th century and early 20th century, Toronto’s primary form of home heating was coal. There was a substantial changeover to oil heating in the mid-20th century. The trans-Canada natural gas line reached Toronto in the 1950s and Toronto’s home heating is now mostly natural gas. Ontario’s history on this issue is probably similar to many North American (and perhaps European) jurisdictions.