Many of us have seen those images displaying what smoking does to your lungs over time. The black, tar-ridden tissue was previously a healthy pinkish-white colour but with consistent inhalation of toxic chemicals, damage was bound to occur.
Below is a video from Backcountry Vapor depicting what those toxins are possibly doing to the lining of the tissues on the way down as well as to the fluid it meets during it's travel into the lungs.
The person performing the experiment incorrectly calculated the nicotine measurements but it would have no effect on the result you see here.
While watching, you may be focused on the water changing to a sickly brown on the smoking side, but you may want to pay attention to the intake tube on that side and the dark stain appearing near the surface of the water.
That's the residue being left on the lining of your tissues!
I don't need to mention too much about the vaping side. The video speaks for itself.
Go ahead, see for yourself: