Smoking pot is almost certainly not good for your lungs. But it is less a problem than tobacco because the amount smoked is far far less. No one I have ever known smoked 20 reefers a day, every day. Anyone who does is on a plane with those who eat 20 cheweseburgere or drink two liters of sweetened soda. Excess in almost everything is bad for you.
Those that worry about the effects of harmful products in pot smoke can use a variety of water pipes or use a vaporizer, which vaporizes the herb without actually burning it, which makes the smoke much less harsh.
No one has criminalized smoking tobacco, either. No one proposes imposing criminal penalties on those who grow, cure, or use tobacco.
I used to be a smoker, but the only effects of tobacco were:
(1) it gave me a slight amount of dizziness the first time I smoked every day. It was not especially pleasant, but not unpleasant, either.
(2) It made me cough a lot.
(3) It increased the probability of getting bronchitis. When I smoked tobacco, I used to get bronchitis almost ever year.
(4) It cost a lot of money, made everything smell pretty awful, and was habit forming.
I smoked cigarettes until I lived in Mexico. There I smoked Mexican cigarettes, Filtrones and Records, mostly. When I returned to the US, American cigarettes tasted funny (because in this period-1966-69- they started adding stuff to them, so I switched to smoking Cavendish tobacco in a filtered corncob pipe. In 1986 I quit, cold turkey.
