Some studies reported a decrease in the number of conventional cigarettes used per day with the concurrent use of e-cigs
The most significant distinction is that carbon dioxide is not toxic, whereas carbon monoxide is highly toxic when inhaled due to its profound impact on the function of hemoglobin
Methods in enzymology 52 , 302310 (1978)
For example, a thrush lesion in the mouth is also white , but it is not an Oral Leukoplakia lesion because it is proven to be caused by the candida fungus
You either have to have multiple disposable e-cigarettes on hand (which kind of defeats the purpose of the convenient disposable if you have to plan for multiple different situations) or risk being without your nicotine for the day
Paper presented at the 2007 National Conference on Tobacco OR Health, Minneapolis, MN, October 2007