Everyone knows the dangers of cigarette smoking, and what it can do to your lungs.
But what about smoking marijuana?
Researchers in California found that study participants who smoked less than one joint per day were able to exhale a large volume of air from their lungs.
Those who smoked more than a joint, and those who smoked cigarettes, could not.
The author of the study says the results are a good guideline for patients who use medical marijuana.
Copyright 2012 KPHO. All rights reserved. CNN News contributed to this report.