cigarette smoke in lungs How Smoking can affect your File:Healthy lung-smokers lung.jpg - Wikimedia

Figure 1.12 PET images of nicotinic receptors in the human brain

An analysis by researchers at the US Food and Drug Administration (FDA) found very low levels of nitrosamines, ethylene glycol and diethylene glycol chemicals associated with cancer and other health risks in some electronic cigarette products, but the levels were a tiny fraction of what a smoker would get from a tobacco cigarette

doi:10.1007/s13181-016-0563-7

[53] Many e-cigarette versions include a power control to adjust the volume of vapor created

E-Cigarettes have become one of the most successful ways to become smoke free, with studies indicating they could be up to twice as effective as other forms of nicotine replacement therapy

Scientific Reports, 4 , 4133