AbstractThe COVID‐19 pandemic has generated a great deal of interest in ultraviolet germicidal irradiation (UVGI) as an important means to disinfect air and surfaces. The traditional lamp employed for UVGI has been the low‐pressure mercury‐discharge lamp that emits primarily at 254 nm in the ultraviolet photobiological band UV‐C (100–280 nm). The recent development of even shorter‐wavelength UV‐C lamps, such as the Krypton–Chloride, 222‐nm lamp, has led to greater concerns about the UV‐C generation of ozone. It is well known that wavelengths below 240 nm more readily generate ozone. However, there is a great misunderstanding with regard to the actual generation and dissipation of ozone molecules by UV‐C lamps. A review of this subject is much warranted. An overview of the ozone generation of various UV‐C light sources is presented to give users a better understanding of risk and how to assure control of ozone when employing UV‐C lamps.