Methods Based on the mathematical models of poisonous gas diffusion and poisoning casualty probability function method which are recommended by Nation Environmental Protection Standards, using computer programming method, the computer software is designed for hazard analysis of toxic gas diffusion. 方法利用国家环境保护行业标准推荐的描述有毒气体扩散的数学模型和中毒伤亡后果分析的概率函数法结合计算机软件开发技术,设计开发毒气扩散危害分析软件。