| 嵊泗地区大气PM2.5中汞形态污染及其与碳组分的关系 |
| 摘要点击 3805 全文点击 1205 投稿时间：2016-07-28 修订日期：2016-09-09 |
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| 中文关键词 海岛 PM2.5 PM2.5中总汞(PBM) 汞形态 碳组分 |
| 英文关键词 island PM2.5 PM2.5-bounded mercury (PBM) mercury species carbonaceous components |
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| 中文摘要 |
| 2014年11月~2015年8月在舟山群岛嵊泗岛上设定采样点采集了4个不同季节的大气PM2.5样品.采用微波消解-原子荧光光度法测定了颗粒物中汞及其不同形态，采用热/光碳分析仪分析样品中有机碳（OC）和元素碳（EC）.结果表明，嵊泗岛上大气PM2.5中总汞（PBM）的质量浓度范围为0.02~1.25 ng·m-3，而单位质量颗粒物中汞的含量为（12.46±18.79）μg·g-1，比陆地城市PM2.5的汞含量偏高.ANOVA分析结果表明，PBM的季节变化规律为：秋季 > 春季 > 冬季 > 夏季.春秋季节汞的质量浓度较高，这表明春秋季节嵊泗地区的汞可能受到外来输送的影响.此外，大气PM2.5中不同形态汞的分析结果表明，惰性汞（RPM）的比例最高，占53.1%.OC、EC均与PBM显示出明显的正相关性，表明碳组分有利于汞的气-粒转化.由于OC/EC比值间接反映了大气光氧化能力的高低，而OC/EC与可溶盐酸汞（HPM）呈显著正相关，这说明高浓度HPM主要来自于大气中的气-粒转化.char-EC/soot-EC与形态汞呈现显著负相关，表明嵊泗地区的大气颗粒汞主要受外界源输入的影响. |
| 英文摘要 |
| PM2.5 samples of four seasons were collected from Nov. 2014 to Aug. 2015 at the site of Shengsi island in Zhoushan islands. Mercury (Hg) and speciated mercury concentrations in PM2.5 samples were measured by Atomic Fluorescence Spectrometry (AFS-9130, China) after digestion with CEM Mars Xpress (PyNN Corporation, USA). The concentrations of organic carbon (OC) and elemental carbon (EC) in PM2.5 samples were determined by thermal/optical carbon analyzer (DRI, USA). The results showed that the daily concentrations of PM2.5-bounded mercury (PBM) ranged from 0.02 to 1.25 ng·m-3. Moreover, the mass content of PBM was (12.46±18.79) μg·g-1, which was higher than those in continental cities. ANOVA analysis result suggested that the highest average mass concentrations of PBM occurred in fall, sequentially followed by spring, winter and summer. Higher concentrations of PBM were in fall and spring, which might be related to biomass burning. In addition, RPM took the highest fraction of 53.1% in PBM, followed by HPM (27.3%) and EPM (19.7%), which might be resulted from the complicated composition of marine aerosols. The strong correlations among OC, EC and PBM indicated that carbonaceous composition may affect the transport of Hg in the atmosphere. The ratio of OC/EC represents atmospheric photo-oxidation capacity, so the positive correlation between OC/EC ratio and HPM indicated that HPM was resulted from atmospheric gas-particle transformation. The negative correlation between Char-EC/soot-EC and mercury species indicated that the atmospheric particle-bounded mercury might come mainly from the input of external mercury sources. |
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