I have an appointment with my doctor tomorrow, and he had asked that I try to quit vaping and switch to nicotine gum because ecigs create formaldehyde in the lungs, which is terrible for you. I know many of you have dealt with this BS, so here's a short, easy-to-read article by a doctor explaining exactly why these studies are ridiculous and misleading. There is much more in-depth stuff out there, but for something by a medical professional that is still very scientific but still easy enough to approach that people will actually read it, I think it's pretty darn good.
The deception of measuring formaldehyde in e-cigarette aerosol: the difference between laboratory measurements and true exposure
The deception of measuring formaldehyde in e-cigarette aerosol: the difference between laboratory measurements and true exposure