Right, so if you breath in 3.6% nicotine, you are exhaling 2.7% nicotine, assuming vapor molecules are as small as oxygen molecules, which they aren't.
Okay, then if you breathe in 2.7% nicotine from secondhand vapor, you exhale 2.1% nicotine from that same vapor.
IOW, if not absorbed from first hand vapor all that much, then how can we, via science, conclude more absorption via SHV?
And if most of it is absorbed via first hand vapor, then there would be arguably barely any available for SHV.
SHV also must take into account that when exhaled, it is nearly always the case that the exhaled mist would be greatly dispersed in the air in a matter of seconds.