Once you breath the isocyanates from the hardener, your body never gets rid of them. I have heard from dozens of sources that a charcoal mask simply will not stop them. I would not take the chance.

I use only an exhaust fan to pull air through filters, with the air sources in the two corners opposite the fan. Everything I paint gets sanded and buffed, so a little orange peel is not a big deal....But if you are trying for an acceptable finish without that step, you had better be able to move enough air to keep the overspray cleared out.