Underground subway platforms are among the world's busiest public transportation systems,but the air-borne transmission mechanism of respiratory infections on these platforms has been rarely studied.Here,computational fluid dynamics(CFD)modeling is used to investigate the airflow patterns and infection risks in an island platform under two common ventilation modes:Mode 1-both sides have air inlets and outlets;Mode 2-air inlets are present at the two sides and outlets are present in the middle.Under the investigated scenario,airflow structure is characterized by the ventilation jet and human ther-mal plumes.Their interaction with the infector's breathing jet imposes the front passenger under the highest exposure risk by short-range airborne route,with intake fractions up to 2.57％(oral breathing)or 0.63％(nasal breathing)under Mode 1;oral breathing of the infector may impose higher risks for the front passenger compared with nasal breathing.Pathogen are efficiently diluted as they travel further,in particular to adjacent crowds.The maximum and median value of intake fractions of passengers in adjacent crowds are respectively 0.093％and 0.016％(oral breathing),and 0.073％and 0.014％(nasal breathing)under Mode 1.Compared with Mode 1,the 2nd mode minimizes the interaction of ventilation jet and breathing jet,where the maximum intake fraction is only 0.34％,and the median value in the same crowd and other crowds are reduced by 23-63％.Combining published quanta generation rate data of COVID-19 and influenza infectors,the predicted maximum and median infection risks for passengers in the same crowds are respectively 1.46％-40.23％and 0.038％-1.67％during the 3-10 min waiting per-iod,which are more sensitive to ventilation rate and exposure time compared with return air.This study can provide practical guidance for the prevention of respiratory infections in subway platforms.

Jianjian Wei;Sirui Zhu;Feiwu He;Qianfang Guo;Xinxin Huang;Jianxiang Yu;Lirong Zou;Tao Jin;Jie Wu

Institute of Refrigeration and Cryogenics/Key Laboratory of Refrigeration and Cryogenic Technology of Zhejiang Province,Zhejiang University,Hangzhou 310027,China;Center for Balance Architecture,Zhejiang University,Hangzhou 310000,China;The Architectural Design&Research Institute of Zhejiang University Co,Ltd,Hangzhou 310000,China;Guangdong Medicine and Food Consulting and Research Center,Guangzhou 511430,China;Guangdong Provincial Center for Disease Control and Prevention,Guangzhou 511430,China;School of Public Health,Southern Medical University,Guangzhou 510515,China

地学前缘（英文版）

[1]Jianjian Wei;Sirui Zhu;Feiwu He;Qianfang Guo;Xinxin Huang;Jianxiang Yu;Lirong Zou;Tao Jin;Jie Wu-.Numerical investigation of airborne transmission of respiratory infections on the subway platform)[J].地学前缘（英文版）,2022(06):236-243

busiest,infector,infectors,iod

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