You basically 'smoked' 150 cigarettes in Montreal last year without even knowing it

If you're the kind of person who swears they'll never touch a cigarette, you might not love this news: just by breathing Montreal's air last year, you may have unknowingly puffed your way through nearly eight packs.

That's the conclusion of a new study by HouseFresh, which ranked global cities by how many cigarettes people are effectively "smoking" due to air pollution. And in Canada, Montreal came out on top (or bottom, depending how you look at it).

According to the data, Montrealers inhaled the equivalent of 148 cigarettes in 2024, the highest number of any major Canadian city included in the ranking.

To raise awareness about the health risks of pollution, HouseFresh translated annual PM2.5 levels into cigarette equivalents using a formula from Berkeley Earth. In short: 22 micrograms per cubic metre of PM2.5 equals one cigarette per day. Multiply that over a year, and you get a surprisingly relatable picture of how dirty the air really is.

Canada's top 10 most polluted cities by 'cigarette' exposure

• Montreal, QC – 148 cigarettes
• Edmonton, AB – 144 cigarettes
• Calgary, AB – 133 cigarettes
• Hamilton, ON – 129 cigarettes
• Winnipeg, MB – 116 cigarettes
• Mississauga, ON – 116 cigarettes
• Toronto, ON – 114 cigarettes
• Brampton, ON – 113 cigarettes
• Ottawa, ON – 100 cigarettes
• Vancouver, BC – 70 cigarettes

Even though no Canadian cities made the global top 20, the Montreal stat is still cause for concern — especially considering how many locals spend summer outdoors in parks, on patios, or biking through the city. Meanwhile, summer 2025 has already featured multiple air quality warnings for Montreal due to wildfire smoke. On July 15, Montreal had the fifth-worst air quality of any major city on the planet, according to IQAir's live global index.

Globally, the worst offender was Delhi, India, with a jaw-dropping 1,797 cigarettes per year, followed by several cities in Pakistan, Bangladesh, and Africa.

You can explore the full rankings, global breakdown, and interactive map via the full HouseFresh study.

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