You can empty and thoroughly clean pens, vaporizers, and cartridges (to where theres no cannabis residue at all), then take them as you would regular vapes
Yes, even hanging around someone who blows clouds can give you a headache, especially in a small room or if you're sensitive to certain flavors or smoke
Your closet and carpet can also smell like cigarettes if you don't wash your clothes after each use
Tob Control 20:e37 Hammond D, Dockrell M, Arnott D, Lee A, McNeill A (2009) Cigarette pack design and perceptions of risk among UK adults and youth
This step would require more research and testing of e-liquid formulations to determine their toxicity (based on dose and delivery through inhalation) with the goal of categorizing the ingredients to create safety standards