大气气溶胶中水溶性有机物的紫外-可见及表面活性特征

Abstract

采集并分析了厦门-金门地区8个站点气溶胶(PM10)中水溶性有机物的紫外-可见光谱及表面活性物质.结果表明,气溶胶颗粒的水溶性有机物与腐殖酸标准具有很接近的紫外-可见吸收光谱,根据E2/E3(250nM吸光值与365nM吸光值之比)计算了水溶性有机物具有较高的芳构化程度(28.7%--34.64%)和分子量(10--19kdA).表面活性剂分析表明,交通繁忙及密集居民区气溶胶颗粒中的表面活性物质的浓度(0.16--0.19μg/M3)比郊区和农村地区高(0.06--0.10μg/M3),且大多表现为东北季风期的浓度高于东南季风期.表面活性剂浓度与颗粒浓度之间不存在简单的函数关系.

PM10 samples from 8 sites in Xiamen-Jinmen area were collected and analyzed for the UV-VIS spectral characteristics and surfactant substances in the water-soluble organic compounds(WSOC).The results showed that the UV-VIS spectra of WSOC were very similar to those of humic acid standards,and the ratio of absorbance at 250 to 365 nm wavelength(E2/E3) showed that the WSOC had much high aromatic content(28.7%--34.64%) and molecular weight(10--19 kDa).The concentrations of surfactant in the WSOC samples collected from busy traffic and compact residential district sites(0.16--0.19 μg/m3) were much higher that those of the suburban and rural sites(0.06--0.10 μg/m3).A seasonal trend was also observed that the concentrations of surfactant in Northeast monsoon samples were almost higher than those of Southeast monsoon samples.There was no simple linear relationship between the concentration of surfactant and PM10.