My point being that smoking marijuana isn't any more harmful to your lungs than sitting in a traffic jam on the freeway and soaking up the CO. Once again, point me to a study that purports to show chronic marijuana smokers dying of lung cancer! Don't waste your time, they're not out there because marijuana doesn't cause lung cancer. Don't you think the critics of normalization haven't looked into this possibility? Marijuana doesn't contain nicotine or the other hundreds of foreign chemicals that are packed into cigarettes and coincidently there are a number of studies out there that purport to show positive health effects resulting from marijuana use, not to mention the clinical evidence represented by the users of medical marijuana. Of course CO from any type of combustion isn't going to facilitate good health, but there are many other ways of consuming marijuana that don't involve CO production. Even so, we're inundated with CO in the air we breath already and smoking marijuana doesn't add significantly to this preexisting condition.