I work with respirators every day the thing to remember is it has to fit well I would not buy one at a hardware store but look up a safety supply. The type of carterage is quite variable a paint fume one (hardware store type) is unlikely to do the job I'd guess an acid gas one would be best but i am guessing. Keep it in an air tight container they work weather you have it on your face or on a table. The life of the cartarages is variable I get about 2 weeks from one but that is with 3 hours a day use.
Alex