Whoa there.

Breathing air with more than ~12ug/m^3 of small particles is considered less than ideally healthy. (This is where PM2.5 comes from.)

Go check out the mass of fine particles per puff:

https://www.ncbi.nlm.nih.gov/books/NBK507187/#_sec_000047_

This is so many orders of magnitude above the “good” AQI threshold that it’s almost comical.

Now, sure, different particles have different health characteristics, but the stuff coming out of a vape isn’t water, and you’d better hope that it is many orders of magnitude less damaging than the fine particles that are found in the environment if you actually want to believe that your lungs are prepared to handle it.

(Okay, it’s obviously orders of magnitude less damaging than, say, wildfire smoke or brake dust or restaurant kitchen exhaust on a per-microgram basis, but the question is how many orders of magnitude less dangerous.)

P.S. I strongly suspect that there is one common dry aerosol that is genuinely harmless in moderate amounts: sodium chloride from sea spray. It’s highly soluble and found all over inside your body. I’m not sure to what extent air quality impact studies try to separate out the AQI impact from sea spray from everything else.