smoking electronic cigarettes Links to E-Cigarette Resources Is Vaping Better Than Smoking?

What we found is that the brain circuits that are activated after a high aversive dose are actually different from those that are activated when nicotine is delivered at a low dose

I would say it's both

Yes, marijuana joints can increase the risk of chronic bronchitis due to similar effects tobacco smokers experience, including respiratory symptoms, lung damage, and inflammation in the large airways, according to numerous studies and the American Lung Association's reports on cannabis use and health risks

This contamination, often called thirdhand smoke, can continue releasing stale cigarette odors long after smoking has stopped