4 research outputs found

    Seasonal Variations in PM_(10) and Associated Chemical Species in Jiuxian Mountain in Fujian Province

    Get PDF
    于2011年3月~2012年1月期间在福建德化县九仙山气象站采集大气了PM_(10)样品,分析了九仙山大气PM_(10)中水溶性离子及二元羧酸,; 对其季节分布与来源进行了探讨。结果表明,九仙山大气PM_(10)、水溶性无机离子和有机二元羧酸的季节分布规律较为接近,都表现为春季的浓度显著高于; 其它季节,但9种二元羧酸对PM_(10)的贡献(0.51% 0.41%)显著低于水溶性离子(18.07 %; 8.73%)。其中,水溶性离子组成以NO_3~-和SO_4~(2-)的浓度为最高,其次为Na~+和NH_4~+;阴离子与阳离子当量浓度、NH_4; ~+与SO_4~(2-)当量浓度,以及NH_4~+与NO_3~-当量浓度之间都存在显著正相关关系。有机二元羧酸的组成以乙二酸的浓度为最高,占测量; 二元羧酸总量的75%左右,且随碳数增加呈逐渐递减趋势;来源特征比值(丙二酸/丁二酸、己二酸/壬二酸)、MODIS火点图及后向轨迹图显示,有机二元; 羧酸主要来自大气二次化学反应过程,生物质燃烧的直接贡献很小。PM_(10) samples were collected at the top of Jiuxian Mountain in Fujian; Province from March 2011 to January 2012 and were analyzed for inorganic; water-soluble ions and dicarboxylic acids to investigate their seasonal; variations and sources. The results showed that PM_(10) and its; associated species exhibited much higher levels in the spring than those; in other seasons but the total contribution of the nine species of; dicarboxylic acids to PM_(10) (0.51% 0.41%) was significantly lower; than that of the water-soluble ions (18.07% 8.73%). The water-soluble; ions were characterized by the highest concentrations of SO_4~(2-) and; NO_3~-,followed by Na~+ and NH_4~+. Significant positive correlations; were observed between cation and anion equivalents,as well as between; NH_4~+ and SO_4~(2-) or NO_3~-equivalents. Individual dicarboxylic acid; showed a monotonically decreasing trend with increasing carbon number in; which oxalic acid accounted for approximately 75% of the total; dicarboxylic acids. Characteristic ratios of malonic acid to succinic; acid and adipic acid to azelaic acid,MODIS fire spots,and backward; trajectories showed that dicarboxylic acids mainly originated from; secondary reactions in the atmosphere and that the direct contributions; of open biomass burning to dicarboxylic acid concentrations were; negligible.国家自然科学基金项目; 国家重点研发计划项目; 福建省自然科学基金计划资助项

    小兴安岭沼泽甲烷通量日变化分析

    No full text
    利用静态暗箱—气相色谱法,研究了小兴安岭7种沼泽类型生长季初期、中期、末期甲烷(CH4)通量的日变化规律,结果表明:小兴安岭沼泽甲烷通量无统一的日变化规律,且与温度和水位两个环境因子的相关性较弱。7个沼泽类型中,仅毛赤杨(Alnus sibirica)沼泽和白桦(Betula platyphylla)沼泽甲烷通量峰值在生长季初期、中期、末期出现的时间大致相同,且都为单峰曲线;苔草(Carex schmidtii)沼泽、灌丛沼泽和落叶松(Larix gmelinii)—泥炭藓(Sphagnumspp.)沼泽甲烷通量的峰值在不同时期出现的时间不同,多数为单峰曲线;落叶松—苔草沼泽和落叶松—藓类沼泽甲烷通量速率较小,多数时间吸收甲烷,没有明显的日变化规律。不同类型沼泽和生长期之间甲烷通量没有统一的日变化规律,说明在进行区域甲烷排放总量的估测时,增加每天的观测频率,或者长期、大量的观测数据可能会对提高估测精度有很大帮助

    湘江长潭株段河床沉积物重金属污染Pb同位素地球化学分析

    No full text
    湘江长沙-湘潭-株洲(简称"长潭株")段是湘江流域重金属污染最严重的河段。以往研究得到沉积物严重受Cd、Cu、Pb、Zn、Mn等多种重金属的污染。但河流沉积物是一个复杂的环境单元,其物质组成既是流域岩石风化的产物,又是人为作用的反映。且湘江流域基岩(如花岗岩等)、土壤等环境介质本身就存在Cd、Cu、Pb、Zn、As等重金属元素高背景值。加上城市工业活动等人为排放,使得沉积物重金属的来源复杂化。因此,认识沉积物重金属
    corecore