气象因素对广州市大气中二噁英污染特征的影响

采用高分辨气相色谱/高分辨质谱仪测定了广州市环境空气中2,3,7,8-PCDD/Fs的含量,并对其来源进行初步分析.重点研究了广州市大气二噁英浓度的空间和季节分布特征,分析其毒性当量浓度变化与气象因素的相关性,并利用美国空气资源实验室的拉格朗日混合单粒子轨道模型对气流轨迹进行模拟,为了解广州市大气二噁英污染状况提供重要的基础数据.结果表明,工业区的二噁英浓度高于其他功能区;大气二噁英毒性当量浓度最高值出现在春季;风向和风速、温度和气压、相对湿度、降水等气象因素都会对大气二噁英的污染程度产生影响,温度、风速与大气二噁英浓度呈负相关,但相关性不明显;经过气团后向轨迹分析,秋季气流轨迹主要往西北地区延伸,冬季大气团运移较慢,主要来自内陆地区,春夏季节气流主要经过东南沿海或海面到达广州.

Effect of Meteorological Factors on Characteristics of PCDD/F Pollution in Guangzhou

High-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) was used to measure contents of 2,3,7,8-polychlorinated dibenzo-p-dioxin and furan (PCDD/F) in ambient air in Guangzhou city, and its sources were traced and tracked preliminarily. Spatial and seasonal distributions, the correlation between PCDD/F concentrations and various kinds of meteorological factors were studied with emphasis, as well as the trajectory of air mass simulated by hybrid single-particle lagrangian integrated trajectory (HYSPLIT) model of the U.S.A Air Resources Laboratory, which will provide important basic data for understanding PCDD/F pollution levels in urban regions. The results show, PCDD/F concentrations in the industrial area are higher than others, and in spring, PCDD/F TEQs are the highest. Meteorological factors, like wind direction and speed, temperature, air pressure, relative humidity, precipitation all have influence on pollution levels of atmospheric PCDD/Fs. Temperature and wind speed has a negative correlation with the concentration, but it is not obvious. By the analysis of the backward trajectory of air mass, something are obtained that the trajectory extends mainly to northwest areas in autumn, and air masses from inland migrate slowly in winter, while they arrive at Guangzhou after passing southeast coast or sea.