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Decay characteristics of aerosolized viruses in the air and control strategy of thermal and humid environment for epidemic prevention

The novel corona respiratory viruses usually leave the host via droplets and float in the air or settle down. Medically, the decay characteristics of aerosolized viruses have been simulated and measured by atomizing suspensions into air, but there has been no systematic study on the effect of ambient temperature and humidity. In this study, we collected experimental data from existing medical studies, then introduced and calculated the initial decay constant (k1) and the secondary decay constant (k2) based on these data as a unified standard to quantify the decay process of the aerosolized viruses. Additionally, the influence of various factors on the decay constant of respiratory viruses in the air was statistically analyzed. The results showed that the phase decay of aerosolized viruses was very evident, and k1 (0.1∼50) was usually one order of magnitude higher than k2 (0.005∼3.2). Furthermore, the relationship between the decay constant and the survival rate of viruses, representing the risk of virus transmission, and the decay time constants, reflecting the effective period of prevention and control, was discussed. According to the decay law, the main contradiction between virus transmission and epidemic prevention and control at different time nodes was pointed out, and scientific measures to reduce the transmission risk in the built environment were recommended.