Analysis on the risk of respiratory virus transmission by air conditioning system operation based on experimental evidence

Abstract

Graphical abstract It is important to know whether SARS-CoV-2 is spread through the air conditioning systems. Taking the central air conditioning system as an example, we analyze the mechanism and potential health risk of respiratory virus transmission in air-conditioned rooms and propose a method to study the risk of virus transmission in central air conditioning systems by investigating the data from medical experiments. The virus carrying capacity and the decay characteristics of indoor pathogen droplets are studied in this research. Additionally, the effects of air temperature and relative humidity on the virus survival in the air or on surfaces are investigated. The removal efficiency of infectious droplet nuclei by using an air conditioning filter was then determined. Thus, the transmission risk during the operation of the centralized air conditioning system is evaluated. The results show that the indoor temperature and humidity are controlled in the range of 20–25 °C and 40–70% by central air conditioning during the epidemic period, which not only benefits the health and comfort of residents, but also weakens the vitality of the virus. The larger the droplet size, the longer the viruses survive. Since the filter efficiency of the air conditioning filter increases with the increase in particle size, increasing the number of air changes of the circulating air volume can accelerate the removal of potential pathogen particles. Therefore, scientific operation of centralized air conditioning systems during the epidemic period has more advantages than disadvantages.

Workplace Design Concept Based on Indoor Environmental Quality Analysis to Prevent Coronavirus Transmission

“…The number of people infected with coronavirus was more found in the workplace with a centralized air conditioning system. This is contrary to the research of [13].…”

“…The target population is workplaces in office buildings that have employees who are infected with Coronavirus 19 and use an air conditioner as an air system, which is divided into centralized air conditioning and split air conditioning. In an air-conditioned room, the system can adjust the temperature and humidity and ensure human comfort to create a quality indoor environment [13]. The research sample is 10 workplaces, namely 5 workplaces that use centralized air conditioning and 5 workplaces that use split air conditioners.…”

“…Rooms that use a centralized air conditioning system and are shared by several spaces, the system must be operated with 100% outdoor air [11]. In rooms with centralized air conditioning systems, where temperature and humidity are controlled in the range of 20-25 °C and 40-70% by central air conditioning during epidemics, it is found to be beneficial for the health and comfort of occupants, also weaken the vitality of the virus and reduce the risk of transmission [13]. The arrangement of office interiors after the pandemic must pay attention to distance, furniture layout, and air conditioning systems [14].…”