Spraying water based paints still puts a considerable amount of particulate matter into the air you're breathing, and quite probably into your lungs unless you're using a good spray booth.
As far as solvent based paints, or two part catalyzed paints, apparently best bet is a filtered booth and a canister type face mask, rated for solvents and organics. A paper mask may not be all that good except for water based paints, although probably better than nothing.
As far as catalyzed 2-part paints, one of the best things I ever read was in an old Model Builder. After hearing how good a certain brand of 2-part polyurethane was, columnist purchased some, and being intelligent, read the label, including health warnings with advise to only apply using a positive pressure breathing mask and full body disposable Tyveck suit. Columnist then called the manufacturer about how serious the warnings were. He reported he was told as far as they were concerned, if while applying the paint, if you smell paint, it might be a good idea to contact your favorite mortuary to make arrangements. The vapors released by the (Probably the catalyst) paint actively attack the pericardium. This is far worse than a general opinion that the only problem is getting paint particles in the lungs.
A couple years later, my company was looking at using a similar product in one of our electronic products assembled in our Canadian plant. The plant engineer refused to allow it in the plant. He cited first the restrictions the Canadian government imposed on the use, and second, having worked at a location where a similar product resulted in several deaths, because of a failure to follow proper safety precautions.