Abstract: Through the real cases ranging from panic buying for isatis root induced by the public opinion of “isatis root may keep SARS away” in 2003 to the behaviors of scrambling for drugs overnight provoked by the public opinion of “shuanghuanglian oral liquid can suppress COVID-19” in 2020, it is not difficult to find that the chain crisis towards public opinion and panic buying (POPB) has seriously threatened people’s normal life and brought enormous challenges on social harmony and stability. Thus, it is of significance and necessity to conduct researches on the evolution law of the chain crisis towards POPB for its emergency response. In view of the impact of information sentiment and environmental noise (ISEN) on the evolution process of chain crisis are rarely considered in the existing studies, a dynamic model incorporating ISEN is proposed to research the evolution law of the chain crisis. Supported by multiple cases study, the structural description on the chain crisis towards POPB from attribute level is firstly constructed, and accordingly, the association between such structural description and system modeling of the chain crisis is established. Based on this, the normative expression of the chain crisis evolution mechanism under the influence of environmental attribute is extracted. Then, the heterogeneous bounded confidence model with environmental noise is extended to depict the impact of ISEN in environmental attributes on participants’ decision-making, and the dynamic model referring to the traditional epidemic model is established to describe the chain crisis evolution. Further, mean-field equations of the proposed model are given, and the roles of ISEN on analytical solution for the reproduction number of chain crisis evolution and stability of POPB-free equilibrium are deduced by using Routh-Hurwitz criteria and LaSalle’s invariance principle respectively. The mathematic derivations show that the increase of positive sentiment orientation or the decrease of negative sentiment orientation and environmental noise tend to result in the lower reproduction number of chain crisis evolution. Also, it can promote the POPB-free equilibrium to reach the local and global asymptotically stability, and the latter stability simultaneously relies on reinforcement effect of panic buying required to be less than a certain threshold. Finally, the chain crisis towards POPB caused by COVID-19 in 2020 is taken as an example to verify the validity of the proposed model and examine the impact of ISEN on the evolution of the chain crisis. The results demonstrate that the evolution tendency on the chain crisis simulated by the proposed model can well approximate the fluctuation of actual data in reality. And compared with the final size, the maximum influence is more pronouncedly impacted by ISEN. Additionally, if the crisis responders take control of the maximum influence of the chain crisis from information sentiment level, the strategies on negative sentiment orientation should be given the priority. The abovementioned research results not only enrich the research contents in the field of chain crisis towards POPB but also bring certain theoretical supports for better coping with it from the view of ISEN.

Key words: public opinion; panic buying; chain crisis; evolution law; information sentiment; environmental noise