宝鸡城区大气中铅污染现状分析

Analysis of atmospheric lead pollution in the urban area of Baoji City

目的分析评价宝鸡市市区大气中铅及其化合物的污染现状，为宝鸡市大气污染治理提供依据。方法在宝鸡市区设置7个点位对大气中铅浓度进行了两期调查监测，同时对宝鸡市区域内煤的主要供应种类进行铅含量测定，及煤炭燃烧和汽车燃油对大气中铅尘的贡献量进行预测，结合市区大气中铅浓度的历史数据以及其他城市的铅污染情况，分析宝鸡市大气中铅的时空分布特征，说明宝鸡大气中铅污染的主要成因。结果宝鸡城区大气中铅尘本底值较低，近20年来成倍增长，但近来开始出现下降趋势，且冬季城区大气中铅尘浓度明显高于夏季；燃煤对大气铅的污染愈发明显，估计宝鸡燃煤对城区大气中铅尘贡献量大约为5～15μg／m^3，汽车燃油贡献量远低于5μg／m^3，但道路扬尘成为宝鸡市大气铅尘污染的一个重要因素，同时铅尘浓度分布也受灰霾和宝鸡特殊地形等因素影响。结论大气中铅尘的总体监测结果与细颗粒物有明显相关。因此需要通过控制颗粒物特别是细颗粒物（PM2.5）来实现对铅尘污染的降低，长远考虑需要逐步调整能源结构，降低燃煤量，加强管理，减少铅尘排放。

Objective--To analyze and evaluate the current pollution situation of lead and lead com- pounds in atmosphere, and provide basis for atmospheric pollution control of Baoji City, Shaanxi Province, China. Methods-- In order to explain the main cause of the atmospheric lead pollution in Baoji, two periods （winter and summer respectively） of air quality monitoring were investigated at seven selected sites in Baoji City, so were both the determination of lead content in several main kinds of coal supply in the urban area of Baoji City and the prediction of lead dust contribution to the atmos- phere from coal combustion and auto fuel. Besides, the characteristic of lead time-space distribution of the atmosphere in Baoji City was analyzed by combining the history data of lead concentration in at- mosphere with lead pollution conditions in other cities. Results-- It is found that the background value of lead dust in the atmosphere in Baoji City is lower. Although this value has multiplied in recent 20 years, it declines recently. The lead dust concentration in urban area in winter was significantly higher than that in summer. Because the coal-burning air pollution is increasing obviously, the amount of lead dust in atmosphere caused by coal combustion was about 5 to 15 μg/m3 , and the value caused by automotive fuel is far less than 5 μg/ma. However, road dust is an important factor leading dust pol- lution in Baoji City. In addition, the distribution of lead dust concentration was affected by others fac-tors such as dust haze and special terrain of Baoji. Conclusion--The overall monitoring results of lead dust in the atmosphere in Baoji City are significantly related to the fine particulate matter in the atmos- phere, so the control of particulate matter, especially fine particulate matter （PMz.5） is needed to re- duce lead dust pollution. In the long term, the measures such as gradual adjustment of energy struc- ture, reduction of coal consumption, management enhancement and reduction of lead dust emission are needed.