eli5: If tobacco is a leaf, why does it have so many substances known to cause cancer?

Question

* Source is the packaging I’ve just read for a pack of tobacco in the UK which says it has 70 cancer causing substances

In: 2

Answer 1

Anytime you burn organic material you produce tons of carcinogenic chemicals. Cigarettes deliver this material straight to your lungs and blood supply.

But we also burn other things, most notably oil/gas/coal and those too create carcinogens which we breath in. The air pollution from fossil fuels [kills millions of people every year](https://seas.harvard.edu/news/2021/02/deaths-fossil-fuel-emissions-higher-previously-thought, which is roughly the same number of deaths tobacco causes each year.