Nah, that's not a dumb question at all!

I don't wear a respirator. Haven't worn one in years. The only time I would ever wear one would be if we went into an industrial area with chemical remnants. Otherwise, the risk of being overly exposed to asbestos is so small, believe it or not, that I don't feel I need to wear one.

The thing one needs to really worry about when entering these places is mold. Having been abandoned for years, most of these places become eco-systems of mold and bacteria unto themselves. A few times after going somewhere, I've had some flu-like symptoms for a few days afterwards. And once a couple years back, my skin somehow came into contact with some sort of bacteria that started eating away at my hand. Luckily, a healthy dose of antibiotic treatments helped to get rid of it.