UVGermicidal

UVgermicidal refers to the use of ultraviolet light to inactivate microorganisms, typically through germicidal ultraviolet irradiation (UVGI). The approach relies primarily on UV-C light, wavelengths about 100 to 280 nanometers, with around 254 nm historically used in lamps and, increasingly, UV-C LEDs being employed. These photons damage nucleic acids, forming pyrimidine dimers in DNA and RNA that disrupt replication and transcription, rendering the organism unable to reproduce.

UVGI is applied in several domains, including air disinfection in heating, ventilation, and air conditioning systems; surface disinfection in laboratories, hospitals, and food processing facilities; and some water treatment processes. Effectiveness depends on the delivered UV dose, exposure time, distance, orientation, and the presence of organic matter or coatings. Microorganisms vary in susceptibility; spores generally require higher doses than enveloped viruses or vegetative bacteria. Shadowed areas and porous materials can limit effectiveness.

Safety considerations are essential: direct exposure to UV-C can injure skin and eyes, so equipment is designed with shielding, interlocks, and warning labels. UV exposure can also degrade polymers and generate ozone at certain wavelengths, so proper use and maintenance are important. Because UVGI acts only on exposed surfaces or air paths, it is typically used in conjunction with routine cleaning rather than as a sole sterilization method. Standards and regulations govern safety, installation, and reporting of UVGI performance.

See also: UVGI, UV-C LED, disinfection.