Multi-stage risk assessment and evacuation strategy for promoting urban resilience in the face of bioaerosol leakage under various meteorological information

In this study, the dynamics of airborne bioaerosol particles originated from different releasing sources under in spring, summer, autumn and winter meteorological factors in Zhongguancun, Beijing were investigated. The quantitative assessment of exposure risks was conducted by integrating a dose-response model within the context of accidental releases of biological materials in the scenarios of biosecurity incidents or terrorist attacks. Based on the classification of high- and medium-risk area, an improved evacuation strategy considering the influence of pre-evacuation time was proposed. Variations of leakage resource and meteorological factors including wind direction, wind speed and even thermal stratification, significantly impact the output of exposure risk. The highly susceptible population with the infection probability between 90 % and 100 % decreased from 12.05 % to 2.98 % of the total population with little change of evacuation distance and time by adopting the exposure-blocking method on summer day. Exposure-blocking algorithm demonstrates superior performance, manifesting a more pronounced reduction in the number of highly infectious individuals (above 50 %) by more than 6000 (10 % of the total population) when pre-evacuation time is prolonged from 120 s to 300 s. The proposed evacuation strategy can be generalized into urban community with various releasing source and meteorological factors.