铅大气污染物环境保护标准限值研究

铅因其对公众健康的影响,其大气污染物标准限值的合理性倍受关注.论文对比分析了国内外铅大气污染物环境质量与排放标准,通过计算提出基于保护环境空气质量的排放标准理论限值及建议限值.分析发现,目前国际上铅环境空气质量标准浓度限值为0.00015～0.0015 mg·m~(-3),但多采用世界卫生组织(WHO)的年均浓度限值0.0005 mg·m~(-3);建议我国今后修订标准时对铅年均浓度和季均浓度限值进一步加严.与发达国家相比,我国铅环境空气质量季均浓度限值水平已显落后;国际上目前各类排放源铅大气污染物排放浓度限值在0.04～2 mg·m~(-3)之间,金属冶炼源等主要源的排放浓度限值在1～2 mg·m~(-3),其他排放源均在0.5 mg·m~(-3)以下;我国铅、锌熔炼源正在执行的排放浓度限值(8 mg·m~(-3))较为宽松,而其他源的铅大气排放浓度限值与国际上的限值基本一致.通过计算认为,保护公众健康的铅大气污染物的理论排放限值为1.2～2.4 mg·m~(-3).考虑到我国的经济技术水平,建议铅、锌熔炼源的铅大气污染物新建企业排放浓度限值为2 mg·m~(-3);其他源的新建企业排放浓度建议限值为0.5 mg·m~(-3).经过过渡期,现有企业应达到新建企业的排放控制要求.铅的企业边界浓度排放限值是保护企业边界附近公众健康的有效屏障,但鉴于铅的污染特性,对于具体建设项目应加强环评力度,提出更具体明确的排放控制要求,并加强对企业周边环境敏感点的环境监测等,采取综合措施保护公众健康.

Research on the lead limit values of environmental protection standards

The limit value of lead in atmosphere should be considered more seriously,due to its significant health effects. This paper analyzed the domestic and international lead pollutants in the environment, particularly its standards about air quality and emission. Through calculation, theoretical limit values of emission based on protection of air quality and suggested emission limit values were proposed. The results indicated that current international lead limit values in ambient air quality standards for air pollutant concentration were between 0.00015 and 0.0015 mg·m^-3 world widely, while WHO''s annual average concentration limit value(0.0005 mg·m^-3) was adopted more and more frequently; China''s lead annual average and quarterly average limit values were proposed to be revised; the current international lead limit values in emission standards were between 0.04 and 2 mg·m^-3, around 1~2 mg·m^-3 for emitting sources and metal melting sources, and under 0.5 mg·m^-3 for all other sources. For lead and zinc melting sources, China''s limit value of emission concentration was around 8 mg·m^-3, which was relatively lower, whereas for the rest of the pollution sources, the limit values were at the same level with the international limit values. Furthermore, the theoretical emission limit value for lead in ambient air was suggested to be between 1.2 and 2.4 mg·m^-3 considering its human health effects. So, it was suggested that the limit values of lead emission concentration for new-built lead and zinc melting sources should be reduced to 2 mg·m^-3; and for all other sources, the limit value for new-built sources to 0.5 mg·m^-3. Given some reasonable transition period, the existing sources limit values should be reduced to be in line with new built sources. In conclusion, in view of lead pollution characteristic, it is necessary to strengthen environmental assessment efforts, propose more effective emission control requirements and take comprehensive measures to protect human health.