I live in an apartment, and on a number of occasions I smelled weed. I don't know whether it harms my health at all or how it would compare to tobacco. The smell was a bit bothersome though.

I recently moved out of Barratt apartment that was built so poorly that I could smell the neighbor's smoke in the bathroom (which was in the middle of the place and had no windows).

Smoke also drifted in through windows.

Makes no difference if it's weed or tobacco.

I don't feel I need to specify pollutants at this point. The smell may be offensive, upsetting, linger. We can discuss potential harm that (along with the general air quality) additional secondhand weed smoke may have on the under three's lungs if you like.

In return, are you suggesting that air quality does not change and there is no need to be concerned in any way whatsoever? Or perhaps you are hinting that the air quality improves in such a scenario?