为调查上海市大气气溶胶中铂元素的污染状况,用PM10-2型可吸入颗粒物采样器采集了上海市大气气溶胶样品,采样时间分别为2003-12~2005-12.用微波消解密闭系统消解样品,电感耦合等离子体质谱法(ICP-Ms)测定了大气气溶胶中Pt的含量.分析结果表明,同清洁对照点((0.65±0.16)Pg·m^-3)相比,上海市中心区大气中Pt((1.69±0.93)Pg·m^-3)的污染是明显的;装有三元催化转化器的汽车尾气中Pt的含量均在100ng·g^-1以上,远远高于大气气溶胶样品(人民广场平均值21.7ng·g^-1);不同交通密度区Pt含量分析结果表明,Pt含量与交通密度紧密相关,这说明装有三元催化器的汽车尾气是气溶胶中Pt污染的主要来源;此外,上海市大气气溶胶中Pt呈现季节性变化,并受气象条件影响.同世界其它城市相比,上海市气溶胶中铂元素污染程度还较低,但是这种潜在的重金属污染应该引起重视.
In order to survey platinum contamination in urban airborne particles, aerosol samples were collected from December 2003 to December 2005 in Shanghai. The aerosol samples were digested using a microwave digestion system, and the resulting solutions were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The analytical results showed that (a) the average Pt concentration in the city center of Shanghai was 1.69 ± 0.93 pg· m^ - 3, (b) the level of Pt in the city center of Shanghai is obviously higher than those in control samples (0.65 ± 0.16 pg· m^ - 3 ) , and (c) the Pt concentrations in exhaust samples collected from vehicles installed with three - way catalytic converters were over 100 ng·g^-1, which was much higher than those in the aerosol samples (mean value of 21.7 ng·g^-1 in People's Square). The results show that automobile exhaust was the main emission source of Pt contamination in urban air. The Pt concentrations in the aerosol mainly depended on the traffic density and meteorological conditions. Compared to other cities in the world, the level of Pt contamination in the atmosphere of Shanghai is rather low; however, attention should be given to preventing further contamination.