Here in BC the Tobacco Control Act prohibits smoking within 3 meters of a window, door or air intake, bus stop, or in common areas of a workplace, hotel or multi unit residential building. You can't smoke in a car with children either.

Beyond that there are Capital Regional District Bylaws prohibiting smoking within 7 metres of the same.

Expect the same to apply to pot smoking, if it is even allowed in public. Can you drink booze in public anywhere in Canada outside of Québec?

https://en.wikipedia.org/wiki/Drinking_in_public#Canada