Baking soda absorbs odors by neutralizing the pH levels in the surrounding environment. Because of its anti-acid properties and how easy it is to obtain, the substance has a variety of household uses.
The scientific name for baking soda is sodium bicarbonate. Sodium bicarbonate is a slightly base mixture, which means that it can stabilize the pH balance of malodorous substances in the surrounding area rather than merely covering them. Sodium bicarbonate itself is completely odorless. Because items that smell tend to be highly acidic, the natural pH-balancing properties of baking soda have the effect of masking the odor. Common sources of odor that can be absorbed by baking soda include sour food in a refrigerator, dirty clothes, cat litter and old books. The substance is even used as an oral anti-acid drug. All of these substances are highly acidic and known for emitting a foul odor. For maximum effect, baking soda should be placed as close to the odorous item as possible. Because of the chemical reaction that occurs when baking soda reduces the pH in the surrounding air, the soda will actually absorb the foul odors. It is necessary to change out a box of baking soda being used for this purpose every week or so to preserve the maximum effectiveness of the compound.