Evolution model and risk analysis of urban haze disaster chain are carried out on the basis of disaster system theory and the complex network theory in this paper. Through the information gathering and analysis of the causes and harm of urban haze disaster, the disaster chain mechanism of urban haze is analyzed, as well as the types and characteristics of disaster chain, according to the characteristics of disaster-causing factors, hazard-formative environment and hazard-affected bodies. By building the urban haze disaster chain evolution network model, qualitative risk analysis is made based on the out-in degrees and number of nodes in its subnets, the shortest path and average path, and the number of branched chains. Finally, the key steps are found and the solutions on disconnecting chains are presented. The results of risk analysis show that in the urban haze disaster chain evolution system, the haze event closely relates to the other crisis events. Through several times of transition, the harm effect might spread to the entire network, and the key links are the decline in atmospheric visibility, the decline in air quality or air pollution, traffic jams or paralysis, traffic accidents, resulting in urban atmospheric acid rain, urban greening, economic losses and endanger human health.

urban haze disaster  /  disaster evolution network  /  disaster chain  /  crisis events  /  out-in degree