Yes. Lungs take in oxygen and pass it along into the bloodstream, which keeps us alive. Any type of second-hand smoke – cannabis, tobacco-related is harmful to the body. Both cannabis and tobacco smoke are made up of similar harmful substances, which are therefore also present in second-hand smoke. Effects include coughing, wheezing, and even light-headedness (as less oxygen is delivered to your blood and brain). Although less conclusively studied, cannabis second hand smoke is damaging to your lungs.