为了解冬季采暖对济南市大气 PM2.5 中汞浓度的影响,在济南市城郊开展了为期超过两年的 PM2.5 样品采集工作,共计采集有效样品 481 个,测定并分析其中的颗粒汞(PHg)浓度和汞含量变化特征.结果表明,济南市大气 PHg 在采暖期的浓度均值为 583.1 pg/m3,约为非采暖期的 1.4 倍,在国内外城市中处于中等偏上水平.济南市大气 PM2.5 对PHg具有极强的富集能力,且在采暖期更强,可能与燃煤等活动排放了更多的超细颗粒物有关.在采暖期,大气 PHg 浓度主要受煤炭燃烧源和交通排放源影响,两者分别贡献了总方差的 39.2%和 16.7%;在非采暖期,气象条件季节性变化、交通排放源、煤炭燃烧源的影响显著,三者分别贡献了总方差的 32.4%、15.8%、12.0%.高浓度 PHg主要来源于分布在采样站点东北偏东方向上的众多燃煤工业企业.此外,济南市大气 PHg还主要受来源于鲁西南地区的区域污染气团的影响,途经污染较重的京津冀地区的污染气团对济南市 PHg浓度也有较大贡献.在非采暖期,济南市 PHg 还受到来自东南和西南方向的清洁海洋气团的显著影响.
To understand the effects of winter heating activities on mercury(Hg)in PM2.5 in Jinan,the concentrations of particulate mercury(PHg)in 481 PM2.5 samples collected over two years at a suburban site in Jinan were measured,and the variation characteristics of PHg concentration and Hg content in PM2.5 were analyzed.The results showed that the average concentration of PHg in Jinan was 583.1 pg/m3 during the heating period,about 1.4 times of that during non-heating period,which was above the mdeium level in domestic and foreign cities.PM2.5 in Jinan had a strong enrichment capacity for PHg and this capacity during the heating period was stronger than those during the non-heating period,possibly due to the increased emissions of ultra-fine particles from activities such as coal combustion.During the heating period,coal combustion and traffic emission were the dominant sources of PHg,contributing 39.2%and 16.7%of the total variance respectively,whereas PHg were primarily influenced by meteorological variations,traffic emission and coal combustion during the non-heating period,contributing 32.4%,15.8%and 12.0%of the total variance respectively.The elevated PHg concentrations were mainly attributed to the numerous coal-burning industries located in the east-northeast of the sampling site.In addition,regional transport from the southwestern Shandong Province and the Beijing-Tianjin-Hebei region also contributed to the high PHg levels in Jinan.In contrast,PHg concentrations during the non-heating period were also strongly influenced by the clean ocean air mass from the southeast and southwest.