Do you know anyone who smoked 40 joints a day?
How about 2 packs of Marlboro?
I don’t smoke anything, but total load matters significantly.
A glass of wine a day won’t hurt you. Three bottles a day will.
40 bones a day? Never that much or even close, but I once was at a party where I was the designated joint roller (due to experience, of course) and lost count after a hundred doobies. Now that party is legendary among those that survived!
I know people who have never smoked cigarettes, but have smoked a couple of bowls every day for 40 years.
They also keep it in their lungs much longer than cigarette smoke.
In any case, chronically deeply inhaling smoke isn’t good for lungs, no matter what is burning.