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

• Published in: Environmental science and pollution research international Vol. 28; no. 40; pp. 56376 - 56391
• Main Authors: Jia, Yonghong, Xiang, Yue, Guo, Shurui, Guo, Lei, Guo, Luyao, Cheng, Zhu, Zhang, Yin, Zhang, Li, Long, Enshen
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2021; Springer Nature B.V
• Subjects: Air conditioners; Air Conditioning; Air Microbiology; Air Pollution, Indoor - analysis; Air temperature; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Carrying capacity; COVID-19 - transmission; Droplets; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Epidemics; Health risks; Humans; Humidity; Pathogens; Relative humidity; Research Article; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Viral diseases; Virus Diseases - transmission; Viruses; Waste Water Technology; Water Management; Water Pollution Control; Central air-conditioned room; espiratory viruses; Virus survival test;,Transmission risk; Environmental regulation; Circulating air
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-14495-0

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.
Graphical abstract