The amount of nic per puff is so small. It's like 1/10th of what's in a cigarette or less, and then the actual person who inhales that again only gets 1/10th of that. Then you exhale it and it's dispersing very quickly and odds are, no one but yourself will get very much nicotine if any at all.
Simply based off this: one cig is anywhere more than 10mg per stick but you actually asorb 1mg or thereabout. If you have 24mg strength nicotine, that's 24mg per millilitre of liquid. One puff is roughly one drop. There is roughly 20 drops per ml. 24/20 = 1.2mg per puff (extremely roughly).
So that's about 1.2mg per puff that's in the vapour. Let's compare to a real cig. 10mg cig or higher, you absorb anywhere just under or above 1mg. 1/10th absorption from something that's specifically designed for quick and good absoption of nicotine. So we actually start with about 1.2mg nic from a 'high' concentration of nicotine (24mg) and you can expect to absorb about 1/10th or less of that again, as the person who is in direct contact with it. 0.12mg of nicotine or even less per puff, as the person who inhaled it directly. That's about 1/100th of what's in a cig nic wise to start with.
Really rough science, based loosely on guesstimates by the tobacco companies that put on the mg amounts on cig packs and guesstimated absorption rates from ecigs as based on some studies that are on the board somewhere.
I think in terms of second hand nicotine you'd be more likely to get higher nic from breathing in second hand breath from someone eating a tomato. Even if they got 'some' nic, it wouldn't be a lot and it's relatively not-that-bad for you anyway.
Edit: Eh, probably not everyone will agree with the 10% absorption rate from ecigs. Controversial as it's not backed up by a lot of studies. Just a guess
