中文摘要：

绿色度方法中各环境影响因子权值的确定非常重要而又颇有争议。本文采用目标值法，通过比较各类环境影响因子的环境现状和目标值，计算得到绿色度方法中各类环境影响因子的权值。提出依据环境政策法规规定的各类污染物的排放阈值来确定目标值，与目标值的其他确定方法相比，本方法避免了采用环境“真实”影响值，可更简捷地用于化工环境影响评价。以北京地区为例，计算结果表明近几年北京地区进行化工环境影响评价时，应重点关注水体人类非致癌毒性、光化学烟雾和富营养化等区域性污染。采用本文确定权值的方法，对合成甲基丙烯酸甲酯的两种化工路线，即异丁烯法（i-C4）和丙烯法（C3）进行了绿色度评价和分析，表明i—C4法路线更为绿色。本研究为绿色度方法用于各地区化工环境影响评价提供了基础。

英文摘要：

The weighting factors of environmental impact categories in Green Degree method are important but difficult to be determined. The Distance-to-Target method is applied in this paper, and the weighting factor is determined as the current value divided by the target value for each impact category. Instead of considering measured environmental impact data, the ＂target value＂ is established mainly based on environmental protection policies and rules, and is convenient for environmental impact assessment of a chemical process. It＇s reasonably concluded that Human Non-Carcinogenic Toxicity to Water, Photochemical Ozone Creation and Eutrophication, should be emphasized much more than other impact categories, when we use Green Degree method to assess the environmental impacts of a chemical process in Beijing. Two chemical routes of producing methyl methaerylate （MMA）, the i-C4 route and C3 route, are compared by the Green Degree method, which shows the i-C4 route has larger green degree value.