Apart from its carcinogenic properties, smoking can increase the incidence of gum (periodontal) disease and post-nasal drip, two of the most important bad breath risks.

Furthermore, in many people, the smoke odor lingers in the mouth itself and mixes with the other smells, resulting in a particularly noxious aroma. Most probably, the smoke components are retained in the mouth itself, rather than in the lung.

Smoke residues in your mouth may lacerate the skin cells, creating a favorable environment for many harmful bacteria to cause infection. This action will invariably affects in bacteria digesting left over food debris and dead cells.