广东南岭大气背景点气态元素汞含量变化特征

利用高时间分辨率自动大气测汞仪(Tekran 2537B),于2012年6月~2013年5月对南岭地区大气气态元素汞(GEM)进行了为期1a的野外观测.结果表明,南岭地区年均GEM含量为(2.56±0.93)ng/m~3,明显高于全球大气汞背景值(1.50~1.70ng/m~3).GEM秋季含量最高(3.03±1.08)ng/m~3],春季最低(2.30±0.69)ng/m~3].日间GEM含量(2.61±0.06)ng/m~3]略高于夜间(2.53±0.07)ng/m~3],峰值出现在17:00.太阳辐射、气温、风速、相对湿度及本地源都对GEM日变化过程有一定的贡献.潜在贡献因子分析(PSCF)结果表明,大气汞的长距离迁移是南岭地区GEM的重要来源,全年南岭地区主要受源自于广西、湖南、广东和江西的大气汞迁移的共同影响.GEM主要源区与主要的有色金属冶炼厂分布有较强的一致性,暗示有色金属冶炼是影响南岭大气汞含量的重要大气汞排放源,而本地局部的燃煤排放也对监测点大气汞含量有一定的影响.

Variation characteristics of gaseous elemental mercury at Nanling mountain background station in Guangdong

Gaseous elemental mercury (GEM) was continuously monitored at Nanling mountain, using the high-resolution automatic atmospheric mercury vapor analyzer (Tekran 2537B) from June 2012 to May 2013. Annual average concentration of GEM was (2.56±0.93)ng/m³, higher than those reported in global background areas (1.50~1.70ng/m³). The GEM concentration exhibited seasonal variation, with the highest and lowest concentrations in autumn(3.03±1.08)ng/m³] and spring(2.30±0.69)ng/m³], respectively. The GEM concentration in the daytime(2.61±0.06)ng/m³] was slightly higher than night(2.53±0.07)ng/m³] with a peak value at 17:00. Solar radiation, temperature, wind speed, relative humidity and local sources made certain contributions to the diurnal variation of GEM. Potential source contribution function (PSCF) indicated that GEM of Nanling area mainly came from long-range transport of mercury, especially from Guangxi, Hunan, Guangdong and Jiangxi province. The strong coherent distribution between main source regions of GEM and the geographical locations of non-ferrous metal smelting factories, suggesting non-ferrous metal smelting was an important mercury emission source, While local coal-fired emission was also a contributor to the GEM in Nanling.