珠江三角洲大气环境VOCs的时空分布特征

在珠江三角洲地区的 8个大气功能区观测点、5个主导风向加强观测点和 3个不同高度监测点进行了为期 1年以上的观测 ,采用美国环保局TO15方法定性并定量分析了 5 5种臭氧前体物 (NMHCs)和 6 2种有毒挥发性有机化合物 (ToxicVOCs) ,系统研究了该地区大气VOC的组成特征及其时空分布规律 .结果发现 ,各大气功能区VOC的浓度水平和组成特征差别明显 ,珠江三角洲大气VOCs呈现区域性污染特征 ;广州市区始终具有最高的VOC浓度水平 ,夏季、冬季其下风向地区的VOC浓度呈现出明显的空间变化规律 ;夏季的NMHC及单环芳香烃的浓度均为全年最高 ,VOC各组分表现出并不相同的日变化和季节变化特征 ;城市近地面VOC主要受机动车排放的影响 ,而越往高空 ,一次污染物去除与二次污染物的影响显得突出和显著

Special and Temporal Distribution Character of VOCs in the Ambient Air of Peal River Delta Region

In this paper, eight regional VOC sites and five enhanced VOC site and three different height sites for one year observe were developed. Applying TO-15 measurement method provided by US EPA, the photochemical smog precursor non-methane hydrocarbons ( NMHC ) and Toxic VOCs (T-VOC ) were measured simultaneously under routine quality assurance and quality control ( QA/QC ) procedures. Based on the analyzed result, the special and temporal distribution of the VOCs' concentrations was researched. The research found the VOCs took on regional pollution in Pearl River Delta, and there were big differences among the VOC levels at every function area. VOCs concentration levels were high in urban area, and dropped down from urban to downwind area in summer time, but first decreased then went up from urban to downwind area in winter. Meanwhile, NMHC and MAH had the highest concentrations in summer, which is much different from current domestic and international findings. VOCs species had different diurnal and seasonal variations. VOC concentrations at the ground-level in urban area were dominated by motor vehicles emissions. Concentration of primary VOCs decreased vertically with height, while secondary VOCs showed different behavior.