Long-term continuous measurements of total gaseous mercury (TGM = gaseouselemental mercury (GEM) + reactive gaseous mercury (RGM)) were conductedsimultaneously along with meteorological variables and a suite of tracegases at an urban site in Nanjing, China from 18 January to 31 December2011. Measurements were conducted using a high resolution mercury vaporanalyzer (Tekran 2537B) with 5-min time resolution. The averageconcentration of TGM was 7.9 ± 7.0 ng m with a range of0.8–180 ng m over the study period. TGM concentrations followed a typicallognormal pattern dominated by a range of 3–7 ng m, which wassignificantly higher than the continental background values(~1.5 ng m) in Northern Hemisphere. The mean seasonal TGM concentrationsdecreased in the following order: summer, spring, fall, and winter. Thisseasonal pattern was quite different from measurements at most other sitesaround the world. We attributed high monthly average concentrations to there-volatilization of deposited mercury during the warm season due to hightemperatures and greater solar radiation. Previous modeling studiessuggested that Nanjing and the surrounding region have the largest Chinesenatural emissions during the summer. Positive correlations betweentemperature, solar radiation, and TGM concentration combined with nocorrelation between CO and TGM in summer provide a strong indication thatnatural sources are important in Nanjing while most sharp peaks were causedby anthropogenic sources. TGM concentrations in Nanjing exhibited anoticeable diurnal pattern with a sharp increase after sunrise and peak ofgreater than 8 ng m during 7–10 a.m. local time. Further,seasonally averaged diurnal cycles of TGM exhibited considerably differentpatterns with the largest variation in spring and insignificant fluctuationsin winter. Using HYSPLIT backwards trajectories from six clusters, it wasindicated that the highest TGM concentrations, 11.9 ng m, was derivedfrom local air masses. The cleanest air masses, with an average TGMconcentration of 4.7 and 5.9 ng m, were advected from the north viafast transport facilitated by sweeping synoptic flows.
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机译：2011年1月18日至2011年12月31日，在中国南京市区，对大气中的总气态汞（TGM =气态元素汞（GEM）+活性气态汞（RGM））进行了长期连续测量，同时还进行了气象变量和一系列微量气体的测量。 。使用高分辨率汞蒸气分析仪（Tekran 2537B）以5分钟的时间分辨率进行测量。在研究期间，TGM的平均浓度为7.9±7.0 ng m，范围为0.8–180 ng m。 TGM浓度遵循典型的对数正态模式，范围为3-7 ng m，显着高于北半球的大陆背景值（〜1.5 ng m）。平均季节性TGM浓度按以下顺序降低：夏季，春季，秋季和冬季。这个季节模式与世界上大多数其他站点的测量结果完全不同。我们将较高的每月平均浓度归因于由于高温和更大的太阳辐射而在暖季期间沉积的汞在那里挥发。先前的模型研究表明，南京和周边地区在夏季的自然排放量最大。夏季温度，太阳辐射和TGM浓度之间的正相关性以及CO和TGM之间的无相关性有力地表明，南京的自然来源很重要，而最尖锐的高峰是由人为来源引起的。南京的TGM浓度呈现出可日变化的日变化模式，在日出后急剧增加，并且在当地时间上午7-10点大于8 ng m。此外，TGM的季节平均日周期表现出明显不同的模式，春季的变化最大，冬季的波动很小。使用HYSPLIT的六个星团的向后轨迹，表明最高的TGM浓度为11.9 ng m，是从当地的空气质量中得出的。从北部向北平流最干净的空气团，其平均TGM浓度为4.7和5.9 ng m，通过快速的气流输送。
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