Baking soda will neutralize the acid, not the vapors, which are hydrogen which as they are lighter than normal air, will rise to the highest point.
If you have an acid problem reaching the floor, chances are you're "boiling" or have over-filled your batteries. Most batteries have a high water mark on the fill neck, and a low water mark. Keep your acid within those lines. If there is no "air gap" at the top of the filler neck at the operating temperature of the batteries you will
expel acid. KEEP your batteries CLEAN! they like it, and will last longer.
It really depends on your enclosure and how many batteries you have within it. You do want positive venting, which can be achieved with a chimney at the highest point of containment, or with a fan.