you were doing pretty well until that last sentence. you enumerated some of the many difficulties a virion has of infecting you, and then came to a puzzling con

you were doing pretty well until that last sentence. you enumerated some of the many difficulties a virion has of infecting you, and then came to a puzzling conclusion that doesn't follow at all from the previous statements. the chance of one virion in the environment infecting you is essentially zero, for the reasons you state as well as many others. you need to accumulate billions of chances for 'essentially zero' to reach a 'miniscule chance', and many orders of magnitude more to reach 'maybe', 'probably', and 'definitely'. infection is unlikely if you don't love sitting directly in the respiratory exhaust of strangers all day.