system
Given the following post, respond as if you're commenting on Reddit:
human
How do some things get absorbed through lung gas exchange (Nicotine) but others don't? (Tar)

I'm essentially wondering how lung gas exchange works for substances other than air. Obviously anything besides air is going to be bad for the lungs but how? Does it leave a film like buildup? Is it permanent? How does vaping compare to regular air?
gpt
The chemicals in the tar are not very soluble in water (blood) and they tend to interact with each other more than water making it difficult to separate tar leading to a build up. The immune system has to remove the tar, which leads to inflammation and cell proliferation and long term it can facilitate the growth of tumors. Vaping has no tar, but it does have oils that can build up in a similar way. Long term effects of vaping are still largely unknown, its likely better than smoking but still far from healthy and possibly even more addictive.