Pot smoking not so harmful to the lungs, study finds
(01-10) 12:55 PST SAN FRANCISCO — Smoking a joint or a bowl from time to time appears to cause no long-term damage to the lungs, according to a UCSF study that disproves one of the major concerns about marijuana use - that inhaling anything other than air on a regular basis must be harmful.
The study, results of which were published today in the Journal of the American Medical Association, found that the lung capacity of people who smoked marijuana was not diminished by lighting up, even among those who smoked once or twice a week.
Smoking 20 or more joints a month did have a negative impact on the pulmonary system, but that level of marijuana use is unusual. For occasional users, smoking marijuana was actually associated with a small but statistically significant increase in lung capacity - perhaps caused by the deep-breathing pot smokers use to draw the drug into their lungs.