A study came out last summer (ish) about the combined effects of marijuana smoking and cigarette smoking. They began with the hypothesis that the combined exposure of smoking marijuana on top of cigarettes created more serious lung problems. I was really interested in the results because my husband smokes both and I wanted to "make a point." The results of the study were eveidently a huge surprise because the research showed that cigarette smokers who also smoked pot had healthy lungs. Maybe all that coughing keeps the tar from attaching