Development of an air purifier with UVC radiation and HEPA filter in the context of COVID-19

ABSTRACT

The transmission of respiratory infections has an important role on human health, especially in the current context of the COVID-19 pandemic. In this work, we present the assessment of an air purifier that uses ultraviolet-C (UVC) radiation and a “High Efficiency Particulate Air” (HEPA) filter as mechanisms to decontaminate indoor environments with low air circulation. To assess the physicochemical and microbicidal characteristics of the equipment, the irradiance produced by the lamp, the flow rate at the entrance and exit of the device, possible changes in the ozone concentration and the equipment's decontamination potential for Staphylococcus aureus, Escherichia coli and Candida albicans. The total dose of UVC radiation that the air receives when passing through the equipment was 801.4 μJ cm^-2, which would represent an inactivation of up to 80% of SARS-CoV-2 in the air. Furthermore, the filtration efficiency dropped with smaller particle diameter, and reduced to around 60% for particles with less than 1 μm and remained above 90% for PM_2.5 and PM₁₀. In microbiological tests, there was a reduction of 99.4%, 99.9% and 99.5% for S aureus, E. coli and C. albicans, respectively, in 11 minutes.

Keywords:
COVID-19; disinfectants; ultraviolet rays; air filters