..."Known by the State of California to Cause Cancer..."
I use the $30-40 respirators at Homedepot and you should be fine. Unless your around this **** everyday then your fine. I've been fine using short sleeves and lots of baby powder, but I'd reccomend wearing sweats and long sleeves taped to your gloves. This is only for sanding, otherwise your fine.
I often glass in a wifebeater and gymshorts with my respirator and googles. You shouldn't have a problem with fiberglas strands when glassin, only when sanding.