The result shows that the risky area is closely related with not only the source term,but also the meteorological conditions and the time after the accident;the high concentration zone spread near the leaking point under the unstable and strong winding meteorological conditions,while,the high concentration zone not only lasts for a long time,but also has the transportation function under the.

It is very complex engineering system for the emergent assistance at the leaking accident of the toxic and harmful gas,and the key to the settlement of the question lies the right determination of the potential risky area.

The systematic analysis and its forewarn mechanism of project regional risk;

A Study on the Response Policy Choice for the Project s Regional Risk Based on the Resource Restriction;

Based on the theory of quantitative risk assessment, a regional risk assessment (RRA) method was put forward.

Information diffusion method for regional environmental risk assessment;

Management of regional environmental risks has come to be one of the key components to assure the safety of regional environment.

It was proposed that comprehensive index of regional environmental risk consists of the danger index of risk source, validity index of control mechanism and vulnerability index of risk receptor.

Establishment of the changeable weight combination forecasting model and its application in regional ecological risk forecasting.;

During the past 20 years,with more studies on the ecological risk assessment,the theories and methods of the regional ecological risk assessment improves greatly,meanwhile the ecological risk management receives widespread attention increasingly.