http://www.npr.org/blogs/health/201...-easier-on-lungs-than-a-cigarette?sc=fb&cc=fp
Not sure how valid the article is, but interesting.
Smoking a joint a week for up to seven years doesn't hurt lung function, according to researchers at the University of California, San Francisco. They came up with that number after following more than 5,000 people for 20 years. The results were just published in JAMA, the Journal of the American Medical Association.
Not sure how valid the article is, but interesting.