Influence of talking behavior of infected patients and the associated exposure risk in a ventilated negative-pressure ward

Negative-pressure isolation ward is a primary choice in preventing the spread of outbreaks and safeguarding patient recovery. Inside the ward, patients with respiratory diseases generate virus-carrying bioaerosols through breathing and talking, posing a very high risk of infection to healthcare workers. In this paper, we used numerical simulation to compare the effects of different respiratory behaviors, such as normal breathing, prolonged talking, short talking, and alternating talking, on the spatial and temporal distribution of aerosols in a ward, and to study the risk of infection for healthcare workers. It was found that a short period of time in which a patient talked in a ward increased aerosol concentrations by four orders of magnitude compared to normal breathing. In the ward with the ventilation of up-supply, or the one with side-supply, the impacts of aerosol generation from talking accounted for 62.4% and 42.6% of the total time, respectively. The overall infection risk in wards designed with side-supply ventilation was lower. Patient talking time changes did not affect high-risk areas. However, when healthcare worker and patient talked alternately, the aerosol impact time was slightly extended. In addition, the aerosols produced by talking were mainly deposited on the beds and floors, leading to higher exposure risk for healthcare workers during direct contact with beds. It is hoped that the results of this study can be used as the data basis for the study of aerosol pollution control strategies in medical scenarios, and provide useful suggestions for reducing the risk of infection.