In order to take care of mold, you need to clean up what you can using hydrogen peroxide. It will foam up when it contacts mold. Keep applying until this is no foam up. Incidentally, peroxide in a spray bottle is great for cleaning showers and places that get mildew. Always use fresh peroxide.
For an air purifier, you need one with a UV light.
For an air purifier, you need one with a UV light.