Sorry I misread the MSDS, the toxicology report was negative, but it still recommends wearing a mask when there is particulate present.
Styrene is noticeable in ppm quantities, so while the smell is not a good sign, it won't harm anyone in limited exposure. If you find yourself in contact with a lot of dust, it might be a good idea to wear a mask
I also forgot to mention that I spoke with a polymers expert yesterday, he said pretty much the same thing, small quantities aren't too much of a problem, wear a mask if it bothers.