Far UV light, also called far ultraviolet or far-UVC, refers to ultraviolet radiation in the wavelength range of 200 to 230 nanometers used for air disinfection. Far UV light sits between traditional UVC (254 nm) and vacuum UV, offering the advantage of inactivating microorganisms while showing reduced ability to penetrate living tissue. This characteristic makes far UV safer for use in occupied spaces.
Technical Details
Far UV light has been demonstrated effective against bacteria, viruses, and fungal spores at doses between 2 and 10 millijoules per square centimeter. The wavelength range of 200 to 230 nm provides sufficient photon energy to damage microbial DNA and RNA. Lamps operating at 222 nm have shown particular effectiveness and safety profiles in peer-reviewed research. Far UV systems typically require 5 to 15 watts of electrical input depending on coverage area.
Applications and Practical Significance
Far UV light technology is deployed in portable air cleaners, in-duct systems, and upper room applications within occupied spaces. The reduced skin and eye penetration compared to standard UVC makes far UV suitable for continuous operation in offices, classrooms, and healthcare settings. Research indicates 222 nm far UV provides 1.5 to 2.5 times greater germicidal effectiveness per unit dose than 254 nm UVC, offering enhanced microbial control with improved safety profiles.