Validation of In-Room UV-C-Based Air Cleaners

The risks to human health posed by airborne pathogens can be mitigated by the use of ultraviolet-C (UV-C) radiation. In general, UV-C-based systems should be applied in a manner that allows effective inactivation of airborne pathogens, while controlling human exposure to below defined limits. Among the methods used to apply UV-C radiation in indoor settings to meet these objectives are UV-C-based air cleaners. These devices can be effective for the control of airborne pathogens, but methods are needed to quantify and validate their performance. To address this need, an experiment-based method and a mathematical model were developed to quantify the effects of UV-C-based air cleaners on the concentration of an aerosolized, viral challenge agent. The method and model were demonstrated to allow quantification of disinfection efficacy and to allow translation of the results from the test environment to the application environment. The primary figure-of-merit from these tests was the clean air delivery rate (CADR), which is commonly used to characterize the disinfection efficacy of these devices. The ability of a validated air cleaner to improve indoor air quality in application settings is simulated based on the measured value of CADR from laboratory tests and the mathematical model.