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.