I wasn't there and I'm not you, so I can't comment on your personal experiences, however, studies have shown that what you're describing is very unlikely, particularly outdoors. A psychological explanation is much more likely.
There is no generalizable “math” involved. Everyone’s physiology is different and their susceptibility to THC depends on the specifics of their exact metabolic conditions in their own body. Some people get high on a few mg. Some people require 10’s of mg. Someone in close proximity to a smoker or smoking crowd could easily get a mg or two if the others are smoking heavy THC strains. The math checks out on that...
