| 霾与非霾期间汞在不同粒径颗粒物上的分布特征 |
| 摘要点击 3462 全文点击 1877 投稿时间：2014-08-21 修订日期：2014-10-06 |
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| 中文关键词 霾 颗粒态汞 粒径分布 大气颗粒物 ICP-MS |
| 英文关键词 haze particulate mercury size distribution atmospheric particle ICP-MS |
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| 中文摘要 |
| 在我国高速经济增长过程中,霾污染日趋突出,同时大气汞污染也十分严重,而颗粒汞对于汞在大气中的循环演化意义重大. 为了探讨霾污染期间汞在不同粒径颗粒物中的分布特征,采用Nano-moudi 12级(6.2~9.9 μm、3.1~6.2 μm,1.8~3.1 μm、1.0~1.8 μm、0.56~1.0 μm、0.32~0.56 μm、0.18~0.32 μm、0.10~0.18 μm,0.056~0.10 μm、0.032~0.056 μm、0.018~0.032 μm、0.010~0.018 μm)大气颗粒物采样器,对上海霾与非霾期间不同粒径大气颗粒物中的汞进行分析. 结果表明,颗粒态汞含量与颗粒物含量正相关; 采样期间霾天颗粒态汞平均浓度0.31 ng·m-3是非霾天颗粒态汞平均浓度0.11 ng·m-3的2~3倍; 霾和非霾天颗粒态汞浓度以及颗粒物质量浓度随粒径分布呈双峰型,霾期间峰值分别出现在0.56~1.0 μm粒径段和3.1~6.2 μm粒径段,而非霾期峰值分别出现在0.32~0.56 μm和3.1~6.2 μm粒径段; 霾天较非霾天颗粒态汞和颗粒物的粒径分布均出现了向大粒径方向偏移; 颗粒态汞主要分布在粒径≤1 μm粒子上,能够长时间停留和长距离输送; 非霾期间颗粒态汞在颗粒物中的平均含量为0.029 ng· μg-1,而霾期间为0.015 ng· μg-1; 霾污染过程中其他污染物迅速成长,而汞成长较慢; 霾天积聚核模态粒子中颗粒态汞质量浓度为2.06 ng·m-3,而非霾天为0.55 ng·m-3,积聚态颗粒物的大幅增加,是灰霾形成的主要原因. 本地源燃煤等的排放以及风沙扬尘的增加和外地源的输送是导致霾天污染严重的重要原因. |
| 英文摘要 |
| With the rapid economic development, China suffers from the severe haze and atmospheric mercury pollution. Particulate mercury transport has an important significance in its global cycle. In order to investigate the distribution characteristics of particulate mercury, 12 degrees Nano-moudi (6.2-9.9 μm, 3.1-6.2 μm, 1.8-3.1 μm, 1.0-1.8 μm, 0.56-1.0 μm, 0.32-0.56 μm, 0.18-0.32 μm, 0.10-0.18 μm, 0.056-0.10 μm, 0.032-0.056 μm, 0.018-0.032 μm, 0.010-0.018 μm) impactor was used to measure the size distributions of atmospheric particulate mercury on both haze and non-haze days in Shanghai. The results indicated that particulate mercury levels were positively correlated with those of the particles. The average concentration of particulate mercury (0.31 ng·m-3) on haze days was 2-3 times than that on non-haze days (0.11 ng·m-3). The mass size distributions of aerosols and particulate mercury showed bimodal distributions. The peak shifted from 0.56-1.0 μm and 3.1-6.2 μm on haze days to 0.32-0.56 μm and 3.1-6.2 μm on non-haze days. The particles with aerodynamic diameter smaller than 1 μm which could stay for a long time and transport for a long distance, had higher particulate mercury concentrations. The average contribution of particulate mercury to total PM aerosol were higher on haze days (0.029 ng· μg-1) than on non-haze days (0.015 ng· μg-1), indicating that secondary particles typically grew faster than mercury during the haze pollution events. The particulate mercury concentration in accumulation mode was 2.06 ng·m-3 on haze days, while it was 0.55 ng·m-3 on non-haze days. The large increase of the accumulation mode particles was a main reason for the formation of haze. Emissions from the coal burning as well as road surface dust and dust from long-range transport accounted for the serious pollution on haze days. |
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