If you want to bring our the beam of your laser a bit more an you don't have fog, you can spray your room with deodarant.
... and create acrolein. No, no and no.It won't ignite. Unless we are talking about Q-switched lasers or the like.
Another alternative is to buy a bottle of glycerine heat up a metal surface e.g. fry pan/spoon/etc.. then put a drop or two on it. It will instantly create enough fog to see a laser beam.
I wouldn't really expose any electronic devices to an environment saturated with water vapor. Not only they're not designed to work in such conditions, but it's common sense. Water condenses and ruins electrical equipment slowly but steadily.You could also use incense or water vapor. Take a hot shower for 10 minutes and then test your laser in the bathroom.