Carbon is not healthy along with other things burning or smoking will create it also makes you cough like crazy. Vaporizer won't make you cough unless set to high temp & taking massive hits. Your friend prob had a crappy pen vape with glass screen to keep plant off the exposed coil they suck hardly produce any vape. read more
How to vape using a vape pen: Tips on getting the most out of a marijuana vaporizer Bans on puffing in public: One Colorado city started looking at an ordinance after someone was spotted vaping in the public library. read more
Vaporizers are much more efficient than smoking (when you smoke a joint, the lit end stays burning and wasting herb), and gram for gram a high quality vape gets me much higher than smoking normally would. read more