Major Study Shows Smoking Marijuana Not Harmful to Lungs, and May be Beneficial

A National Institutes of Health study published in the American Medical Journal looked at 5,000 smokers as well as non-smokers over twenty years.  The study concluded that lung function was not reduced even when smoked up to the amount of a joint per day for seven years.  The study also found that usage does not play a factor in chronic pulmonary obstruction disease (COPD), a major killer among smokers of cigarettes.  To the contrary, the study found that lung functioning may actually improve.  The study did not look at the link between smoking marijuana and cancer, and public health officials encouraged caution about the findings, noting that smoking marijuana use can contribute to short-term problems with attention, memory, motor skills, and motivation.

Source:  http://well.blogs.nytimes.com/2012/01/11/marijuana-smoking-does-not-harm-lungs-study-finds/