I would want some more protection if I were you. I would at the very least till you get a trap cut a 2 inch square piece of some panty hose, or ladies nylon and place it over the bottom of your airbrush and thread the hose over it, this will act as a crappy filter, then trim off the excess panty hose. This will at least stop any debris from getting up in your airbrush TEMPORARILY!! I would check it after you are done painting and see if anything gets caught in it.
Josh