Baking soda is a great natural deodorizer. You can use it as an inexpensive air freshener, but you may not want a box of Arm and Hammer sitting on your bathroom counter. Here is an easy and cute way to make a baking soda air freshener.
Approximate Time: 20 minutes
By Laurel from Port Orchard, WA
April 14, 2012
This is from the ask a scientist website.
The popular "open box of Arm & Hammer in the refrigerator" simply provides an adsorbent material that can soak up odors - but not very effectively. For example, if some of the odoriferous materials floating around in the refrigerator are acidic, the alkaline baking soda can absorb and neutralize the acid. Even in that regard, it is not all that effective because, as the powder in the box contacts water vapor, it tends to crust over an lose a great deal of its already limited surface activity.
It all sounds quite nice, but it does not work very well. Far better would be a canister of activated charcoal because it can indeed adsorb vapors that contact the charcoal.