A vehicle includes a transparent panel provided on an external surface of the vehicle and spaced from an internal component part disposed at a vehicle inner side and an exterior member at least one of whose end portions is adjacent to the transparent panel and which is disposed on the external surface so as to be substantially parallel to the transparent panel. Multiple light sources may permit a single apparatus to have the capability of emitting multiple, preselected wavelengths. The measurement gas chamber has a volume of 0.