cigarette cards framed Vintage Tennis Card, c. 1936, "Service" Antique Framed Will's Cigarettes Cards

A strategy for efficiently collecting aerosol condensate using silica fibers: Application to carbonyl emissions from e-cigarettes

United States patent application 15/679849 (2019)

this study supports the need for higher levels of nicotine-containing liquids (approximately 50 mg/ml) in order to deliver nicotine more effectively and approach the nicotine-delivery profile of tobacco cigarettes

[149] The majority of the e-liquids analyzed contained NNN from 0.34 to 60.08 g/L and NNK from 0.22 to 9.84 g/L

Fire and Explosion Risks Unlike tobacco cigarettes, e-cigs pose an explosion risk due to their lithium ion batteries