北京市典型重污染过程中PM2.5载带水溶性无机离子污染特征分析

为研究北京地区冬季PM_(2.5)载带的水溶性无机离子组分污染特征,2013年1月在中国环境科学研究院内采用在线离子色谱(URG-9000B,AIM-IC)对PM_(2.5)中水溶性无机离子(SO_4~(2-)、NO_3~-、Cl~-、NH_4~+、Na~+、K~+、Mg~(2+)、Ca~(2+))进行监测与分析。结果表明,采样期间总水溶性无机离子(TWSI)浓度为61.0μg/m~3,其中二次无机离子SO_4~(2-)、NO_3~-、NH_4~+(SNA)占比达72.3%,在PM_(2.5)中占比为40.29%,表明北京市PM_(2.5)二次污染严重。重污染天[NO_3~-]/[SO_4~(2-)]表明,固定源污染较移动源更为显著。三元相图表明,在空气质量为优的情况下,NH_4~+(在SNA中占比为30.3%~65.5%,下同)主要以NH_4NO_3的形式存在,较少比例以(NH_4)_2SO_4存在;严重污染时,NH_4~+(47.3%~77.9%)主要以(NH_4)_2SO_4形式存在,其次以NH_4NO_3的形式存在,其余的NH_4~+以NH_4Cl的形式存在。[NO_3~-]/[SO_4~(2-)]日变化表明,早、晚机动车高峰影响北京重污染发生。     

蚌埠市夏季大气细颗粒物在线源解析

为了解蚌埠市环境空气中PM_(2.5)的来源,于2017年8月18日—9月18日,在百货大楼和高新区站点,利用单颗粒物气溶胶飞行时间质谱仪开展PM_(2.5)在线源解析。结果表明,百货大楼点位ρ(PM_(2.5))高于高新区点位,轻度污染比例(4.2%)明显高于高新区点位(0.8%),出现了中度污染(0.3%);SPAMS的PM_(2.5)质谱图显示百货大楼点位PM_(2.5)中K~+、Na~+特征明显,高新区点位HSO_4~-、NO_3~-、NO_2~-等无机信号较为明显;2个点位NO_3~-、NO_2~-、NH_4~+离子颗粒数占总颗粒数的百分比明显较高,且高新区点位NO_3~-、HSO_4~-离子数占比要明显高于百货大楼点位,燃料燃烧、工业工艺源、农田氮肥施用是其主要的人为污染源;2个点位PM_(2.5)成分主要为元素碳,分别占比42.4%,40.6%;污染时段,ρ(PM_(2.5))快速上升,除受本地机动车尾气源和燃煤源累积影响外,百货大楼点位扬尘源排放增加,高新区点位扬尘源和工业工艺排放源增加;2个点位机动车尾气源均为首要污染源,分别占比29.5%和30.9%,其次为燃煤源(24.3%和24.7%),扬尘源占比分别为22.9%和20.8%。     

大同市大气颗粒物浓度与水溶性离子季度分布特征

为研究大同市大气颗粒物质量浓度与水溶性离子组成特征,于2013年2、7、9、12月,分别对大同市及其对照点庞泉沟国家大气背景点进行了PM2.5及PM10的采样,通过超声萃取-IC法测定了样品中的9种水溶性离子,结果表明,大同市大气颗粒物污染1、4季度重于2、3季度,PM2.5季度均值全年均未超标,PM10仅第1季度超标1.4倍,污染状况总体良好,PM2.5与PM10相关系数R为0.75,说明大同市颗粒物污染有较为相近的来源,且不同季节均以粗颗粒物为主;大同市PM2.5中水溶性离子浓度分布为SO2-4、NO-3、NH+4Cl-、Ca2+K+、Na+F-、Mg2+,PM10中Ca2+浓度仅次于SO2-4、NO-3,控制扬尘将有效降低PM10的浓度;PM2.5及PM10中的9种水溶性离子在不同季度的浓度与颗粒物浓度分布规律类似,1、4季度较高,2、3季度较低;由阴阳离子平衡计算结果可知,相关性方程的斜率K为1.045,表明大同市大气颗粒物中阳离子相对亏损,大气细粒子组分偏酸性。NO-3与SO2-4浓度比值均小于1,大同市以硫酸型污染为主,大气中的SO2-4主要来源于人类活动排放。     

重庆市主城区大气水溶性离子在线观测分析

2015年12月—2016年3月期间,利用在线气体与气溶胶成分监测仪(IGAC)在重庆市大气超级站开展连续观测分析,并捕捉到2次持续时间较长的空气重污染过程。对PM_(2.5)中9种水溶性离子及5种气态前体物的观测结果分析表明:NO_3~-、NH_4~+和SO_4~(2-)是重庆市主城区PM_(2.5)中主要的水溶性离子成分,其浓度均表现出明显的日变化特征,主要以(NH4)_2SO_4和NH_4NO_3的形式存在。NH_3和SO_2是最主要的气态污染物。2次重污染过程的水溶性离子组分有明显差异,细颗粒物累积型污染的NH_4~+、SO_4~(2-)、NO_3~-浓度高,二次转化十分明显;春节期间烟花爆竹集中燃放,Cl~-、K~+浓度高,主要属于一次排放;污染期间主要离子组分的同源性特征显著。     

徐州市不同类型颗粒物重污染过程特征及组分差异性分析

经过多年的大气污染防治,我国空气质量有了大幅改善,但重污染过程仍有发生。对2018—2021年徐州市3种不同类型颗粒物重污染过程的污染特征、演变趋势、PM_2.5组分特征和相关性及污染成因分析结果表明:在不同类型的重污染过程中,二次无机离子NO₃^-、SO₄^2-、NH₄⁺在PM_2.5中的占比均是最高。在累积型重污染期间,NO₃^-、SO₄^2-、NH₄⁺分别增长144%、142%、183%,二次无机离子对PM_2.5的增长贡献较大。结合相关性分析及SOR、NOR值发现,硝酸盐和硫酸盐的二次生成作用显著。在沙尘型重污染期间,结合雷达监测结果及后向轨迹图可以看出,沙尘沉降至高空与近地面污染物叠加造成颗粒物高值。化学组分中Ca²⁺、Mg²⁺浓度对PM_2.5浓度的影响最大,二次生成和转化对其影响较小。在烟花燃放型重污染期间,和烟花爆竹有关的K⁺、Mg²⁺、Cl^-离子较污染前分别上升1 112%、2 058%、和239%,对污染过程影响显著。     

重庆市黔江区降水地球化学特征

为了解生态旅游城市重庆市黔江区大气污染状况,2015年采集了91个降水样品,分析了降水中离子组分分布特征,运用富集因子法、海盐示踪法、相关性分析、主成分分析、聚类分析和HYSPLIT模型分析了降水化学组分来源。研究结果表明:黔江区域降水p H为5.66~6.96,加权平均值为6.34,降水离子组分浓度大小次序为SO_4~(2-)Ca~(2+)NH_4~+Mg~(2+)NO_3~-Cl~-Na~+K~+F~-,SO_4~(2-)、Ca~(2+)之和占总离子的63.95%;除Mg~(2+)和K+外,其余组分离子浓度与总离子浓度随季节变化(冬季春季秋季夏季)呈同样的变化特征。Ca~(2+)、Mg~(2+)和K+大部分均来源于陆源贡献,Na~+可能受到了海洋源的影响,SO_4~(2-)和NO_3~-主要来源于人为输入源的贡献,Cl~-是受土壤物质和海洋的双重影响。轨迹水汽运输结果表明:黔江区域的降水主要受到西北气团、西南季风、西风环流和极地气候共同作用输入。降水中各个离子组分均表现出显著性或极显著性关系,主成分分析结果表明,第一主成分上研究的降水离子组分中都具有相对较大正载荷,第二组分pH、降水量和气温为一类。     

上海青浦地区大气降水的化学特征

利用上海青浦地区2003—2014年观测的大气降水监测资料,分析该区域12 a以来大气降水的酸化程度、化学组成特征,探讨降水中化学成分的不同来源及相对贡献。结果表明:降水pH年均值为4.43~6.33,酸雨频率为2.6%~86.8%,降水酸化程度大致经历了明显恶化和波动变化2个阶段。降水电导率年均值为1.77~4.01 m S/m,呈下降趋势。降水中各离子雨量加权平均当量浓度顺序为SO_4~(2-)NH_4~+Ca~(2+)NO_3~-Cl~-Na~+Mg~(2+)F-K~+,SO_4~(2-)、NH+4、Ca~(2+)和NO_3~-是降水中的主要离子,占离子总量的83.0%;降水类型由硫酸型向硫酸和硝酸混合型转变。降水离子中的二次组分SO_4~(2-)、NO_3~-和NH_4~+绝大部分来源于人为源,Ca~(2+)、Mg~(2+)和K+主要来自于土壤源和人为源的贡献,Cl~-主要来自海洋源,同时人为源的影响也不可忽视。     

Factor analysis and linear regression model (LRM) of metal speciation and physico-chemical characters of groundwater samples

An approach is described for viewing the interrelationship between different variables and also tracing the sources of pollution of groundwater of north Chennai (India). The data set of 43 variables which include major ions, minor ions and trace metal speciation (Cu, Pb, Cd and Zn) collected during the pre-monsoon and post-monsoon seasons of the year 2000–2001, was subjected to R-mode factor analysis to comprehend the distribution pattern of the said variables. It was found that first factor measures salinity and hardness which explained 19.12% of the total variance (comprised of variables EC, TDS, Na⁺, K⁺, Ca²⁺, Mg²⁺, total hardness, Cl⁻ and SO₄ ²⁻) during pre-monsoon, while it was 25.08% during post-monsoon. The second and third factors were attributed to speciation of zinc and copper ions during both pre-monsoon and post-monsoon. Although there were two more factors, loaded with speciation parameters of lead and cadmium, the variance of them were less than 10%. From this study it is seen that sea water intrusion, municipal solid waste disposal are the identified sources of component of pollution. The importance of metal ions is taking a secondary role and the anthropogenic origin-industrial activity, is the reason in the evaluation of pollution status as they come in the second, third, fourth and fifth factors. As the trace metal speciation was grouped in separate factors, linear regression model (LRM) with correlation analysis was applied to check its validity for prediction of speciation and to apply LRM for rapid monitoring of water pollution.     

Assessment of the sources of suspended particulate matter aerosol using US EPA PMF 3.0

The main purpose of this paper was to carry out a source apportionment of suspended particulate matter (SPM) samples using positive matrix factorization procedure. The central and local Government of Japan introduced strict emission regulations in 2002/10 and 2003/10, respectively, in curbing SPM pollution from major metropolitans. This paper also highlighted the impact of the measures taken by the central and local Government of Japan on the reduction of SPM and the contributions of sources. SPM samples were collected for 6 years starting from 1999 to 2005 at two sites, i.e., site A (urban) and site B (suburban) of Yokohama, Japan. Microwave digestion and inductively coupled plasma-mass spectroscopy (ICP-MS) were employed to measure Mg, Al, Ca, V, Cr, Mn, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and Bi, while water soluble ions (Na⁺, NH₄  ⁺_{4}^{\ \,+}, K⁺, Ca^2 +, Mg^2 +, Cl⁻, NO₃  ^-_{3}^{\ \,-} and SO₄  ^2-)_{4}^{\ \,2-}) as well as carbonaceous mass (EC and OC) were analyzed using ion chromatograph and CHN analyzer, respectively. The sources identified at two sites were automobile, soil dust, marine aerosol, mixed sources, and secondarily formed aerosol. Also, source quantification was performed. Automobile and soil dust were striking contributors at site A. Automobile and soil dust of SPM aerosol might be produced from local origin at current study areas. Besides, Asian dust had an impact on high concentrations of SPM aerosol in some certain period of the year due to the outflows of East Asian emission. In contrast, secondary aerosol in the form of sulfate and ammonium as well as mixed sources (coal, long-transported Cs, and other unknown sources) were remarkable at site B. Stationary/industrial combustion has apparently more impact on the release of SPM components at site B than A. Automobile regulations in 2002 and 2003, respectively, resulted in reduction of SPM by 28% for site A and 16% for site B. There was also net reduction of automobile contribution at both sites due to the above measures being implemented.     

1997—2010年北京市大气降水离子特征变化趋势研究

依据北京市环境保护监测中心1997—2010年降水监测资料,分析北京地区降水中离子特征及变化趋势,阐明北京市降水污染现状及变化特征。结合北京市特有的气象条件、地形地貌和工业分布情况,分析污染物来源及污染变化趋势。研究表明:年度降水电导率呈现波动变化,降水污染严重程度依次为南部郊区>市区>北部背景点。北京地区大气降水中的主要阳离子成分是Ca²⁺和NH₄⁺,主要阴离子成分是SO₄^2-和NO₃^-。近年来[SO₄^2-]/[NO₃^-]比值逐步下降,污染类型由典型硫酸型发展为硫酸+硝酸混合型。阳离子[Ca²⁺]/[NH₄⁺]比值下降,碱性离子缓冲能力降低。9种离子各季节浓度变化趋势基本一致,由高到低依次是春季>秋季>冬季>夏季,这种季节变化特征与气象因素密切相关。相关性及聚类分析表明:NO₃^-与SO₄^2-存在很强相关性,说明其前体物SO₂和NO_X在大气中经常一同排放且进入降水途径相同;H⁺浓度不是由某个离子决定,是所有致酸离子和中和离子相互作用的结果,而NH₄⁺来源不同于其它离子,北京地区的氨存在其单独排放源。