2016—2017年中国中东部本底地区PM10化学特性

Chemical Characteristics of PM10 at Background Stations of Central and Eastern China in 2016-2017

  • 摘要: 对中国中东部3个区域大气本底观测站2015年12月—2017年12月PM10质量浓度及其化学成分空间分布与季节变化特征进行研究,结果显示:研究期间龙凤山站、临安站和金沙站平均PM10质量浓度分别为57.5,62.2 μg·m-3和57.6 μg·m-3。其中临安站和金沙站2017年PM10质量浓度较2016年有所下降,但龙凤山站有所上升。与2013年相比,临安站和金沙站平均PM10质量浓度分别降低29.3%和26.2%。临安站SO42-,NO3-和NH4+平均质量浓度分别为9.9,8.2 μg·m-3和3.7 μg·m-3,金沙站分别为10.2,6.7 μg·m-3和2.6 μg·m-3,均高于龙凤山站的5.9,4.9 μg·m-3和2.1 μg·m-3,其中龙凤山站和临安站的NO3-与SO42-质量浓度比值较高(0.9和0.8),金沙站较低(0.6)。龙凤山站的有机碳(OC)和元素碳(EC)质量浓度分别为10.1 μg·m-3和2.7 μg·m-3,临安站为6.7 μg·m-3和3.1 μg·m-3,金沙站为4.7 μg·m-3和2.3 μg·m-3,即龙凤山站OC最高,金沙站最低,3个站点的EC基本相当,临安站略高。与2013年相比,研究期间临安站SO42-,NH4+和OC分别下降38.1%,26.0%和55.6%,金沙站分别下降46.3%,51.9%和44.7%,但临安站和金沙站的NO3-分别上升12.3%和15.5%;临安站EC下降27.9%,金沙站EC上升4.5%。3个站点夏季PM10,NO3-,EC质量浓度及NO3-与SO42-质量浓度比值均最低。

     

    Abstract: The characteristics of PM10 and its chemical composition from December 2015 to December 2017 are studied at three regional atmospheric background stations (Longfengshan, Lin'an, and Jinsha) in central and eastern China. The water-soluble ions (F-, Cl-, NO3-, SO42-, PO43-, Na+, K+, NH4+, Ca2+, Mg2+), carbon-containing compounds (OC, EC) and main elements in PM10 samples are analyzed. The average PM10 concentration at Lin'an (62.2±36.6 μg·m-3) during the whole period is the highest, followed by Jinsha (57.6±31.8 μg·m-3), and that at Longfengshan (57.5±55.3 μg·m-3) is the lowest. At those stations, the annual PM10 mass concentrations are lower than the national second-level air quality standard. The concentrations of PM10 in 2016-2017 show a downward trend, with the reductions of concentrations about 29.3% at Lin'an and 26.2% at Jinsha compared with the results during the year of 2013.The concentrations of SO42-, NO3-, and NH4+ during the whole period are 9.9, 8.2 μg·m-3 and 3.7 μg·m-3 at Lin'an, and 10.2, 6.7 μg·m-3 and 2.6 μg·m-3 at Jinsha, respectively, which are all higher than those at Longfengshan, with the average concentrations of 5.9 μg·m-3 for SO42-, 4.9 μg·m-3 for NO3-, and 2.1 μg·m-3 for NH4+. However, the ratio of NO3-/SO42- at Longfengshan and Lin'an are relatively higher. The concentrations of OC and EC during the whole period are 10.1 μg·m-3 and 2.7 μg·m-3 at Longfengshan, 6.1 μg·m-3 and 3.1 μg·m-3 at Lin'an, and 4.7 μg·m-3 and 2.3 μg·m-3 at Jinsha. Compared to the year of 2013, the concentrations of SO42-, NH4+ and OC during the whole period decrease by 38.1%, 26.0%, and 55.6% at Lin'an, respectively, and decrease by 46.3%, 51.9%, and 44.7% at Jinsha, while the concentrations of NO3- increase by 12.3% and 15.5% at Lin'an and Jinsha, respectively. The concentrations of EC decreases by 27.9% at Lin'an, but increases by 4.5% at Jinsha. The ratio of NO3-/SO42- increase obviously at all the stations, which indicates the increases of nitrate aerosols, due to the continuously control of coal combustion emissions and increase of car ownership.The seasonal concentrations of PM10, NO3-, EC and the ratio of NO3-/SO42- are lowest in summer at three stations. Meanwhile, the mass concentrations of SO42-, NO3- and NH4+ are basically higher in winter than in other seasons.

     

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