Comparison table of commonly used ultraviolet sterilization irradiation doses, including bacteria, viruses, fungi, spores, etc

Application and sterilization principle of ultraviolet light

According to wavelength, ultraviolet (UV) light is usually divided into UVA (315~400 nm), UVB (280~315 nm), and UVC (200~280 nm). The wavelength UVC band, also known as the "sun blind" band, is almost non-existent in the near Earth solar spectrum due to the strong absorption of ozone in the atmosphere

The main applications of UVC include disinfection/purification of water/air/surfaces, analytical instruments (spectrophotometry, liquid chromatography, gas chromatography, etc.), and mineral analysis. The UVC band has a short wavelength and high energy, which can quickly destroy the molecular structure of microbial organisms (bacteria, viruses, and other pathogens) in cells. By disrupting the DNA and RNA of microorganisms to prevent their reproduction, it can achieve efficient and rapid broad-spectrum sterilization effects, thereby sterilizing water, air, and object surfaces, making cells unable to regenerate. Therefore, it is widely used in sterilization and disinfection of water, air, and other substances. Data shows that with only 30 mW/cm2 of UVC ultraviolet irradiation intensity, almost 100% killing of most bacteria can be achieved in one second, and the effect is very significant, which can be widely used in the medical and health fields. In the field of personal health and home hygiene, ultraviolet light can be used for disinfecting water cups, bowls and chopsticks, air purification and sterilization, killing insects, disinfecting shoes and socks, and disinfecting baby bottles, with countless applications

UV sterilization effect

According to the different types of microorganisms, the UV sterilization time and dosage also vary. Different bacterial species have different absorption peaks for ultraviolet radiation. The maximum absorption wavelengths of DNA and Escherichia coli are both 265 nm, while the maximum absorption wavelengths of Cryptosporidium and bacteriophages are 261 nm and 271 nm, respectively. Therefore, the required sterilization time should also be different. When the ultraviolet radiation intensity is 3 × 104 μ W/cm2, the time required to kill viruses and bacteria, mold spores, algae and bacteria is 0.1-1.0 s, 1.0-8.0 s, 5.0-40.0 s, respectively. According to the research team of Dong Xiaoping, an expert from the Institute of Viral Disease Control and Prevention of the Chinese Center for Disease Control and Prevention, UVC radiation with an intensity greater than 90 μ W/cm ² can kill the SARS virus in 30 minutes

The dosage of ultraviolet radiation plays a crucial role in the sterilization process. UV dose can be expressed as the product of UV intensity and irradiation time. Under sufficient UV dosage, inactivated virus and bacteria will not be resurrected, but when the dosage is insufficient, many virus and bacteria that have been inactivated by UV irradiation can repair their damaged structures with the assistance of light. When the UV dose is the same, high-intensity, short-term or low-intensity, long-term irradiation can be used to achieve sterilization. To kill 1 × 104 spiral bacteria/mL, a UV dose of about 30 mJ/cm2 is required, while to kill the same number of spores, a UV dose of about 70 mJ/cm2 is needed

Dosage of commonly used ultraviolet sterilization irradiation