i've been to a pulmonary doc before because ive had small problems with my breathing+minor chest pains and discomfort in recent years and the guy had told me i had asthma(and he came to the conclusion that it was most likely from my marijuana smoking) after giving me some weird breathing test, i laughed it off and tossed his prescription in the trash on my out of his office. Well almost two years later i guess it turns out he was right because i also had an asthma attack when all this happened and the only thing that made me feel better and start breathing normally again was when the ER room gave me some bronchodialtors(same thing that's in an asthma inhaler). Also marijuana is carcinogenic, just not as much as cigs(but some docs and studies have said and shown it to be more carcinogenic actually). Sure smoking occasionally isnt going to do anything to you, but im not an occasional smoker. We had to bury one of my younger friends father just a few months ago because of lung cancer, was a lifelong weedsmoker. My old neighbor had a tank of air with him wherever he went because he smoked weed everyday for over 30 years, never touched tobacco. One of my buddies has similar issues to what i had but much worse, he gets shortness of breath and labored breathing almost everytime he smokes up and bunch of them have numerous other problems, almost all linked to heavy smoking. Very rarely will you find heavy smokers who have been smoking weed for their whole lives that dont have some kind of issue because of it. So yea sure at best it can be a nice relaxing way to end the day, but at worst it can definitely kill you and fuck your lungs up. And according to those x-rays and the doc i have some air that has escaped one of my lungs and is stuck between my lungs and breastbone, they literally said i have tiny little hole somewhere in one of my lungs(which is where the air is coming from) but it didnt show on the x-ray because (in his words) "it's probably somewhere on the inside and an x-ray wont catch it we would need to do a CT scan". I didnt believe him since he couldn't show me on the x-ray where the hole was but when i got a few other opinions on it they all said the same thing, that it's most likely not going to show on just a plain x-ray. Basically if this got worse instead of getting better, i was going to have a collapsed lung, which you even know because you mentioned "per-collapsed lung" in one of our PM's. Doctor said the same thing by saying if i left i was most likely going to be back there with a collapsed lung. I'm glad to say he wrong on that part