The measure of volatile sulfur compounds can be performed by an organoleptic evaluation of the air emanating from the oral cavity through gas chromatography or the use of a sulfide monitor, such at the Halimeter (Interscan Corporation), which determines the amount of volatile sulfur compounds in parts per billion (ppb) in the exhaled air. Gas chromatography is the most appropriate means for detecting halitosis of different origins. In 2004, the Oral ChromaTM (Abilit Corporation) was developed in Japan for the individual measurement of the three main gases (hydrogen sulfide, methyl mercaptan and dimethyl sulfide), allowing the evaluation of the intensity and origin of halitosis.