# Causality Analysis and Risk Assessment of Haze Disaster in Beijing
## 3 Results and Discussion
### Suggestions on Haze Controlling of Multiple Urban Regions  
The above experiments show that cross-regional joint governance is the best way to solve the haze problem in Beijing. According to the causal relationship of haze formation analyzed above, the optimization path of the regional governance policy is as follows: first, promoting public transport and new energy vehicles to reduce exhaust emissions; second, adjusting the industrial structure and developing the green economy; third, adjusting the energy structure and replacing fossil fuels, such as coal, with clean energy; fourth, improving the carrying capacity of the urban ecological environment; and, lastly, establishing a mechanism of cross-regional coordinated governance between Beijing, Tianjin and Hebei to achieve common development.  
Considering the level of economic development in the Beijing, Tianjin and Hebei region, there is a big gap. It is necessary to ensure the maximization of regional interests and establish a good benefit compensation mechanism in the process of the cross-regional collaborative governance of haze reduction. To achieve effective cross-regional collaborative governance in the Beijing-Tianjin-Hebei region, the following suggestions are put forward: (1) form a strong driving force. All regions in Beijing, Tianjin and Hebei need to form a clear understanding of the urgency of haze pollution control. Local governments, enterprises and the public should actively participate in making joint efforts toward haze control; (2) build solid trust. Confidence building is the basis of dialogue and synergy and is extremely important in solving cross-region problems and conflicts of interest. All regions of Beijing, Tianjin and Hebei should be based on the common goal, that is, to eradicate haze pollution, establish firm and full trust and jointly contribute to haze control; (3) ensure good political support. In the comprehensive cooperation strategy to control cross-regional haze pollution, the political support of governments in Beijing, Tianjin and Hebei plays an important role and determines whether the cooperation policies and measures can be successfully implemented. In short, the economic development of Beijing, Tianjin and Hebei is different, and the corresponding policies for haze pollution control are also different. When formulating relevant environmental protection policies, local governments in Beijing, Tianjin and Hebei should take into account the governance measures of the region and cooperation with surrounding regions, and further promote the collaborative governance of haze pollution based on policies.  
In order to realize the cross-regional collaborative governance of haze pollution in Beijing, Tianjin and Hebei, we should form multi-level, cross-regional institutional arrangements and determine accurate policy plans and detailed implementation plans, so as to ensure the efficient promotion of haze governance. In the process of haze control, we should also pay attention to the cost sharing of pollution control, eliminate the conflict of interest between regions in the process of haze control and stabilize the cooperative relationship.