I guess what I'm asking is if anyone knows how the results compare to exposure from just walking down the street on a given day.
Not a scientist, here, but off the top of my head, I'm guessing it would be almost impossible to estimate on-the-street exposure rates, since components would tend to vary widely depending on location and would probably vary widely minute to minute in the same location.
That being said, I have seen somewhere a comparison of vapor constituents to allowable OSHA workplace levels. Darned if I can find the link just now, tho...