The characteristics of large passenger flow and high density of people in the public transport increase the infection risk of respiratory infectious diseases among passengers in the public transport. Ventilation plays a decisive role in reducing the risk of infection of passengers in closed public transport. In this study, discrete phase modeling was used to simulate the propagation characteristics of droplet nuclei carrying SARS-CoV-2 based on different ventilation. The modified Wells-Riley model was used to quantitatively assess the infection risk of SARS-CoV-2 spread by droplet nuclei on the elderly with low immunity in the public transport. Results show that ventilation is essential to reduce the risk of infection among the elderly in the caring seats in the public transport. The air change rate per hour determines the infection risk of SARS-CoV-2 in the elderly. Personalized air supply angles will also affect the spread and distribution of droplet nuclei carrying the new coronavirus in the public transport, thereby affecting the risk of infection for the elderly. It follows that good ventilation is essential to prevent the spread of SARS-CoV-2 through droplet nuclei and the development of COVID-19.

SARS-CoV-2; The elderly; Ventilation; Wells-Riley model; Infection risk