Toronto air quality is currently among the worst in the world

 https://toronto.ctvnews.ca/toronto-air-quality-currently-among-the-worst-in-the-world-1.6458972

Air+quality has its good days, but then the bad days really hit so hard.

https://toronto.citynews.ca/2023/06/28/the-big-smoke-photos-capture-toronto-air-quality-wildfire-smoke/

https://globalnews.ca/news/9798277/southern-ontario-air-quality-deteriorated-wildfires/

https://www.cbc.ca/news/canada/toronto/toronto-air-quality-wildfire-smoke-1.6891013

It's certainly not any better in Chicago or Detroit.

https://www.npr.org/2023/06/28/1184746530/why-haze-wildfire-canada-midwest

https://www.usatoday.com/story/news/nation/2023/06/27/chicago-midwest-hit-by-canada-wildfire-smoke/70360124007