Some substances have the properties that enable them to absorb ultraviolet light of a specific wavelength, and the concentration in the gas can be obtained by irradiating the ultraviolet light and measuring the amount of light transmitted. This principle can be used in ozone analysis equipment, as well as TOC (total organic carbon), protein, Sox, NOx, chlorine, etc., and similar principles can be used for analysis.

In order to analyze these items, UV mercury lamp is usually used. However, there are various limitations in size and voltage. By using deep UV LED in the analyzer, miniaturization and low power consumption can be realized.