化学事故引发城市灾害的危险识别与控制

城市化学灾害属于局域性环境灾害的范畴。工业性化学事故列首要危险。由流动事故源引起的化学灾害更难控制。对20世纪（1900－1996）139个国家和地区的运输化学事故进行统计，造成城市灾害的概率在0．73％－2．10％。由灾害源和孕灾环境构成的灾害系统中，众多因素共同影响导致灾害发生。孕灾环境不仅包括自然环境要素，还包括社会环境要素。人类对很多环境灾害至今缺乏认识，尚不能在真正意义上防灾。但人类可以控制引起灾害的危险化学品，可以控制能影响和抵御灾害的承灾体能力。大部分城市化学灾害原因基本清楚，可以也应该实行防灾、抗灾和救灾三级预防。

HAZARD RECOGNITION AND CONTROL OF CITY DISASTERS CAUSED BY CHEMICAL INCIDENTS

City chemical disaster belongs to the category of local environmental disaster. The industrial chemical incident is the primary danger in the city chemical disaster. The chemical disasters caused by the mobile accidental sources seem more difficult to be controlled than those occur in the factories. The transport chemical incidents from 139 countries and regions in the 20th century( 1900 ~ 1996 ) are counted for 0.73% ~ 2.10% of the probability of city chemical disasters.Among the disaster system consisting of the disastrous source and the environment impregnated with disaster, numerous factors jointly influence and cause the occurrence of calamity. The environment impregnated with city chemical disaster not only includes the factors of natural environment, but also includes the factors of social environment of cities. To this date, human still lack of knowledge of many environmental disasters and cannot control disasters in real meaning yet. Human can control the dangerous chemicals that induce disasters, and can control the carrying capacity of environment that influences and resists disasters. Therefore, we can, and should, implement 3 levels of precautions, i.e. preventing disaster, fighting against disaster, and rescuing from disaster.