As part of our ongoing study on verification of helium–alternative carrier gases in the official test method using gas chromatography–mass spectrometry (GC–MS) for chemicals in indoor air, we examined the applicability of hydrogen and nitrogen to thermal desorption (TD)–GC–MS. A comparison of the signal–to–noise ratios of standard solutions of volatile organic compounds (VOC) and Phthalate esters showed that detection sensitivities of hydrogen and nitrogen analyses were sufficient for the official test method. Measurements using these alternative carrier gases showed good linearity and could quantify less than 1/100^th of Japanese guideline values for indoor air concentrations. Therefore, hydrogen and nitrogen gases can be applied to the official test method using TD–GC–MS for VOC and Phthalate esters in indoor air as alternative carrier gases to helium.