Evaluation of the Droplet Removal Behavior by a Small Air Cleaner with Photocatalyst

Abstract

A small air cleaner with the visible-light-responding photocatalyst was developed. This air cleaner is specialized in removal of the splashed droplets which flies between facing peoples to cope with various infectious diseases. Photocatalyst of a tungsten trioxide system which response efficiently to visible-light was sprayed on a conventional nonwoven fabric filter with a visible-light LED module and a silent type fan are applied. The photocatalyst was excited by visible-light to generate active oxygen that oxidizes and decompose various organic matters. In this study, the physical performance of the air purifier was estimated, 1) the removal action of splashed droplets from the oral cavity with special motion-picture system, 2) evaluation of the transmittance of droplets to the filter and 3) droplets capture performance in a clean bench. Furthermore, performance of the photocatalyst system was evaluated by formaldehyde gas decomposition rate in a small chamber. As a result, droplets of 5 micrometers or more can be removed effectively by the small air purifier, and it is considered that the virus contained in the droplets caught by the filter will be inactivated with the photocatalyst by degrees.