ABSTRACT
The importance of effective ventilation as one of the measures against COVID-19 is widely recognized worldwide. In Japan, at the early stage of the pandemic, in March 2020, an official announcement was made about basic ventilation measures against COVID-19. WHO also used the term 'long-range aerosol or long-range airborne transmission';for the first time in December 2021. Based on the aerosol infection control measures before 2021 by the Japanese government, we conducted experiments on methods related to partition placement as an element of effective ventilation methods. In July 2022, the governmental subcommittee on Novel Coronavirus Disease Control provided an emergent proposal about effective ventilation methods to prevent two types of aerosol infection;infection by large aerosol on the air current and infection by small floating aerosol diffusion in a room. They also showed the way of setting droplet prevention partitions, which do not block off ventilation based on this investigation's results.
ABSTRACT
Information on air-conditioning and ventilation has been continuously disseminated in response to the Japanese Government's announcement of the need for appropriate ventilation measures against the new coronavirus disease (COVID-19), and the issuing of an emergency presidential discourse by the presidents of Engineering Societies. In this paper, we add to the information the latest knowledge on the behavior of SARS-CoV-2 in air, describe its diffusion characteristics in the built environment, and summarize the effects of temperature and humidity on the virus. Then we recommend varying approaches of air-conditioning control for facility type.