Risk-based personal emergency response plan under hazardous gas leakage: Optimal information dissemination and regional evacuation in metropolises

Knowledge on the characteristics of regional evacuation based on optimal information dissemination in hazardous gas leakage in metropolises plays a critical role. We established a risk analysis model for residents combining optimal emergency information dissemination and evacuation simulation in order to guide residents to make appropriate personal emergency response plan in hazardous gas leakage. The model was developed considering eight influencing factors, type and flow rate of hazardous gas, location of leakage source, wind speed and direction, information acquirement time, leakage duration, state of window (open/closed), and personal inhalation. Using Beijing as a case study, we calculated the risk of all grids and people and also obtained the three-dimensional special risk distribution. Through the microcosmic personal evacuation simulation in different condition, detailed data were obtained to analyze personal decision-making. We found that residents who stay near to the leakage source had better stay at home because of high concentration of hazardous leakage on their evacuation route. Instead of evacuation, staying at home and adopting optimal stay plan is very efficient if residents can receive the emergency information before the hazardous gas totally dispersed. For people who lived far from leakage source, evacuation is usually a good choice because they have longer time to avoid high-concentration hazardous gas.