Professor Wen Ju, director of the dermatology department of the Second People's Hospital of Guangdong Province, introduced that ultraviolet rays are electromagnetic waves with a wavelength of 100-400 nm. According to different wavelengths and biological functions, it is mainly divided into three bands, namely long-wave ultraviolet UVA, medium-wave ultraviolet UVB and short-wave ultraviolet UVC. Ultraviolet light accounts for about 13% of sunlight, UVA accounts for about 97% in nature, and UVB only accounts for 3%. The ultraviolet rays used for sterilization are mainly short-wave ultraviolet UVC. Generally speaking, the shorter the wavelength of ultraviolet light, the stronger the lethality.

Professor Wen Ju introduced that ultraviolet disinfection lamps are mainly used for air disinfection. At present, indoor air disinfection in most hospitals in China is carried out by using ultraviolet disinfection lamps and ultraviolet sterilizers. This method is simple and easy. The wavelength range emitted by the inner surface of the ultraviolet lamp is 200-270nm, and the central wavelength of sterilization is 253.7nm, which belongs to short-wave ultraviolet. This ultraviolet ray mainly kills microorganisms (bacteria, viruses, spores and other pathogens) by damaging and destroying the function of nucleic acid by radiation, thus achieving the purpose of disinfection.

Long-term ultraviolet radiation will lead to skin pigmentation, skin thickening and roughness, photoaging, and even precancerous lesions, skin cancer, cataracts and so on. Therefore, long-term ultraviolet radiation should be avoided. However, short-term exposure to ultraviolet disinfection lamps mainly causes electro-optic ophthalmia and skin damage, and other carcinogenic risks are minimal. "Sterilization ultraviolet lamp is short-wave UVC, which has extremely weak penetration and mainly causes the greatest damage to the skin surface. How much harm ultraviolet disinfection lamp does to human body depends on power and irradiation time. "