百色市右江区大气PM10中水溶性无机离子的化学特征与来源

2010年10月至2011年9月采集百色市右江区大气PM10样品,分析PM10及其水溶性无机离子的化学特征与来源。结果表明:(1)百色市右江区大气PM10为13.89～319.44μg/m3,年均117.48μg/m3,年均值超过《环境空气质量标准》(GB 3095-2012)二级标准(100μg/m3)。百色市右江区大气可吸入颗粒物的污染主要出现在春冬季节。(2)水溶性无机离子浓度年均值依次为SO24->NO3->Cl->NH4+>K+>Na+>Mg2+>F-,SO24-、NO3-和Cl-浓度最高,分别占水溶性无机离子的57.7%、14.9%和14.5%。(3)百色市右江区大气PM10呈较强的酸性,高浓度的SO42-可能是导致百色市右江区大气PM10呈较强酸性的主要原因。(4)PM10的季节变化受气温和风速的影响极显著;气象因素对SO42-、NO3-、F-的影响不显著。(5)主因子分析表明,PM10中水溶性无机离子可能来自3个方面,Cl-和NO3-主要来自于当地低烟卤煤燃烧排放的烟气;Mg2+、K+和Na+主要来自于自然源;F-、SO24-和NH4+主要来自于混合源。     

西安夏季PM2.5中碳组分与水溶性无机离子特征分析

2012年8月6日—22日利用大气细颗粒物水溶性组分在线监测分析系统和大气气溶胶OC/EC在线分析仪在线分析了西安PM2.5中的水溶性无机离子和OC、EC,并结合气溶胶前体物SO2、NO2和部分气象参数的监测数据进行了分析。结果表明,PM2.5中OC、EC和主要水溶性组分SO2-4、NH+4和NO-3的比重分别为:14.34%、5.35%、26.32%、12.90%和11.28%;以有机物(OM)为主要成分的总碳气溶胶(TCA)在PM2.5中的质量分数为28.30%,其中光化学反应导致OM中二次组分(SOC)高达45.30%;对主要水溶性组分之间的相关性分析发现,NO-3、SO2-4、NH+43种主要组分之间的结合形态为(NH4)2SO4和NH4NO3,对Mg2+和Ca2+的相关分析反映其有多种共同源;此外,硫氧化率(SOR)和氮氧化率(NOR)均较高,表明大气中存在较强的光化学反应。PM2.5的各组分因子分析得到4个主要来源(机动车尾气和燃煤、土壤建筑尘和生物质燃烧、二次硝酸盐气溶胶、二次硫酸盐气溶胶)。     

天津工业区冬春季大气PM2.5的组成特征及来源分析

选择2020年12月(冬季)和2021年3月(春季),对天津工业区大气细颗粒物(PM_2.5)中的半挥发性有机物(SVOCs)、水溶性无机离子(WSIIs)进行检测,分析其组成特征、季节变化及来源。结果表明,天津工业区冬春两季PM_2.5中SVOCs的质量浓度均值分别为(276.23±197.56)、(180.30±94.46) ng/m³,主要成分是酯、含杂原子化合物,且冬季SVOCs的浓度大于春季。WSIIs均以SO₄^2-、NO^-₃和Na⁺为主,冬春季二次无机气溶胶SO₄^2-、NO^-₃、NH⁺₄(SNA)的平均质量浓度分别为(34.60±21.61)、(30.88±16.46)μg/m³,且春季SNA在总水溶性无机离子(TWSIIs)中的占比大于冬季。冬春两季大...     

珠三角地区大气PM_(2.5)理化特性季节规律与成因

基于珠三角大气超级站2013年8月至2014年3月PM2.5、PM2.5中主要水溶性无机离子组分及其重要气态前体物等参数的逐时在线监测结果,揭示当地大气PM2.5中二次无机组分与其气态前体物的相互作用,以及PM2.5理化特性与成因的季节差异。结果表明,观测期间,PM2.5、PM10的年平均质量浓度分别为64.2、105.1μg/m3,PM2.5在PM10中所占比例(PM2.5/PM10)平均为61.1%。SO2-4、NO-3、NH+4的年平均质量浓度分别为16.6、9.0、10.2μg/m3,3者之和(SNA)占PM2.5的比例(SNA/PM2.5)平均为55.8%,体现了二次转化对珠三角地区PM2.5污染的重要影响;不同季节,SNA/PM2.5为46.0%~64.3%,夏季最低,冬季最高,其中SO2-4、NH+4对PM2.5的贡献相对稳定,NO-3贡献的季节差异较大;秋、冬季各项观测参数浓度的日变化规律相对明显,夏季除HNO3和NH3外,多项观测参数在低浓度水平波动,日变化规律不明显;珠三角大气中具有足量气态NH3以中和硫酸盐和硝酸盐,PM2.5中NH+4、SO2-4、NO-3主要以(NH4)2SO4和NH4NO3形式存在;本研究站点夏季的硫氧化率和氮氧化率均高于广州市,这充分体现了该站点的区域性特征。     

西安采暖期PM2.5及其水溶性无机离子的时段分布特征

为了探讨西安市采暖期大气颗粒物PM2.5及其水溶性无机成分的污染水平,于2010年1月4日—2月1日按一天8个时段(每个时段3 h)连续采集PM2.5样品四周,每周更换一次滤膜。结果显示,西安市采暖期PM2.5的质量浓度时段差异较大,呈现明显的双峰分布特征:21:00—24:00时段(147.516μg/m3)和09:00—12:00时段(141.678μg/m3)。4种被测水溶性无机组分总浓度为39.801μg/m3,占PM2.5总浓度的30.5%。SO24-和NO3-是最主要组分,占到4种无机组分的86.2%。各离子间相关分析显示,Cl-只与NO3-有较强的相关性,表明机动车尾气对Cl-有较大的贡献。SO24-和NO3-时段分布规律较为相似,与PM2.5浓度的时段分布特征相反:在PM2.5污染最轻的15:00—18:00时段,SO24-和NO3-的相对含量达到一天中的最高浓度时段,而在PM2.5双峰时段,它们的含量有所降低。     

西安市冬、夏两季PM2.5中碳气溶胶的污染特征分析

为研究西安市冬、夏两季大气颗粒物PM2.5中碳组分的污染变化规律,利用TEOM系列RP1400a采样仪于2010年冬季和夏季进行采样,测定了样品中的有机碳(OC)、无机碳(EC)和水溶性有机碳(WSOA)的含量。结果显示,PM2.5中OC和EC的季节平均浓度值冬季较高,分别是夏季的2.62,1.75倍,这表明西安市冬季碳气溶胶污染严重。OC和EC日变化在不同季节均呈现双峰分布特征,这主要是由交通源的排放和不利的气象条件造成的。OC和EC在冬、夏两季都有较强的相关性(R2分别为0.823和0.543),且OC/EC平均值分别为5.36和3.58,均大于2,表明采样各时段有二次有机碳(SOC)生成。     

宝鸡市冬季城郊水溶性离子浓度的昼夜变化及粒径分布特征

为研究宝鸡市冬季城郊水溶性离子浓度的昼夜变化及粒径分布特征,用分级采样器在宝鸡市城区和郊区同步采集2017年12月至2018年1月大气颗粒物,用离子色谱法分析9种离子的粒径分布。结果表明:(1)宝鸡市PM2.1(粒径≤2.1μm的细粒子)和PM2.1(粒径2.1μm的粗粒子)均呈郊区高于城区、夜间高于昼间的特征,PM2.1是颗粒物主要组成部分。二次离子(SO24-、NO3-和NH4+)是水溶性离子的主要成分,且主要存在于PM2.1中。城郊NO3-/SO24-(质量比)均大于1.6,表明宝鸡市移动污染源贡献大;(2)城郊PM2.1、PM2.1及6种主要离子均呈双模态分布,二次离子主峰分布于0.43～1.10μm粒径段,Ca2+、Na+、K+的主峰分布于4.70～5.80μm粒径段;(3)不同粒径段的硫氧化率(SOR)和氮氧化率(NOR)均呈双模态分布,主峰分布于0.43～1.10μm的细粒径段,说明在PM2.1中更易发生硫氧化反应和氮氧化反应。人为活动及车流量的昼夜时段性差异是造成城郊SOR和NOR差异的重要原因。     

西安南郊采暖期大气颗粒物PM_（2.5）的污染特征分析

为研究西安市南郊地区采暖期大气颗粒物PM2.5的污染浓度及水溶性成分,使用颗粒物采样器于2009年1月6日-2009年2月15日进行PM2.5采样。将24 h分为8个阶段,每天3 h定时采样。结果表明,西安市南郊地区采暖期PM2.5明显污染,24 h中PM2.5污染状况最严重的时段为21：00-23：59;PM2.5中NH4^＋、NO3^-和SO42^-是其最主要的水溶性组分,在PM2.5中的平均质量混合比分别为10.225%、13.698%和15.650%,三者在PM2.5中质量混合比最高的时段分别为06：00-08：59、03：00-05：59和18：00-20：59。     

天津冬季PM2.5与PM10中有机碳、元素碳的污染特征

研究了天津冬季PM2.5和PM10中碳成分的污染特征.结果表明,天津冬季PM2.5和PM10的平均质量浓度分别为(124.4±60.9)、(224.6±131.2)μg/m3;总碳(TC)、有机碳(OC)与元素碳(EC)在PM2.5中的平均质量分数比在PM10中分别高出5.0%、3.6%、1.2%;PM2.5中OC、EC的相关系数较高,为0.95,表明OC、EC的来源相对简单,可能主要反应了燃煤和机动车尾气的贡献.OC/EC的平均值在PM2.5和PM10中分别为3.9、4.9.次生有机碳(SOC)在PM2.55和PM10中的平均质量浓度分别为14.9、23.4/μg/m3,分别占OC的48.5%(质量分数,下同)、49.8%,OC/EC较高可能主要与直接排放源有关;PM2.5中的OC1与OC2的比例明显高于PM10,而聚合碳(OPC)的比例又低于PM10,同时PM2.5与PM10中的EC1含量均较高,表明天津冬季燃煤取暖和机动车尾气是重要的污染源.     

武汉市秋、冬季大气PM_(2.5)中水溶性离子污染特征及来源分析

采用离子色谱法测定武汉市秋、冬季大气PM2.5中水溶性离子浓度,对其化学组成、质量浓度变化特征及源解析等方面进行了研究。结果表明,NO-3、SO2-4、NH+4为武汉市秋、冬季大气PM2.5中主要的水溶性离子,相关性分析表明,燃烧源是秋、冬季大气PM2.5中水溶性离子的共同来源。成分分析表明,工业区的水溶性离子主要来源于燃烧源,交通区的水溶性离子主要来源于二次污染源,其中包括垃圾焚烧源,植物园的水溶性离子主要来源于二次污染源。     

辽宁省区域性空气污染的天气分型

应用2003-2004年主要污染物浓度和气象资料,对辽宁省全年的PM10产生的区域性3级空气污染进行环流分型,按污染源划分为冬季煤烟型、春季沙尘型和夏秋大雾型.其中冬季煤烟型又分为长白山高压地形槽型、高压内部均压场型、东北高压脊,西部倒槽型、蒙古高压前均压场、蒙古低压前均压场、高压内部小范围均压场型6个型;春季沙尘型分为东北低压型、南大风型和干冷锋北大风型;夏秋大雾型分为低压槽型和低压前均压场.上述类型几乎概括了近两年PM10 3级污染的所有个例,为大气环境质量预报、总量控制等提供依据.     

控制大气颗粒物的经济效应预测研究

大气颗粒物仍然是全球大气污染的主要影响因子.许多研究表明,可吸入颗粒物(PM10)浓度上升与疾病的死亡率、发病率关系密切,由此对经济产生直接或间接的影响.以香港为研究对象,通过流行病学研究和对健康影响评估,来预测和评价10年期效的减排措施获得的价值.结果显示,减排措施达到清洁空气的目标后,社会可以获得7.6亿至43.3亿港元的间接潜在收益.     

Properties of organic matter in PM2.5 at Changdao Island,China—A rural site in the transport path of the Asian continental outflow

Fifty-five seasonal PM_2.5 samples were collected March 2003–January 2004 at Changdao, a resort island located at the demarcation line between Bohai Sea and Yellow Sea in Northern China. Changdao is in the transport path of the continental aerosols heading toward the Pacific Ocean in winter and spring due to the East Asia Monsoon. Solvent-extractable organic compounds (SEOC), organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) were analyzed for source identification based on molecular markers. This data set provides useful information for the downstream site researchers of the Asian continental outflow. Total carbon (TC, OC+EC) was ∼18 μg m⁻³ in winter, ∼9 μg m⁻³ in spring and autumn and a large part of the TC was WSOC (33% in winter, >45% in the other seasons). Winter and spring were the high SEOC seasons with n-fatty acids the highest at ∼290 and ∼170 ng m⁻³, respectively, followed by n-alkanes at ∼210 and ∼90 ng m⁻³, and polycyclic aromatic hydrocarbons (PAHs) were also at high at ∼120 and ∼30 ng m⁻³. High WSOC/TC, low C_18:1/C₁₈ of fatty acids, and low concentrations of labile PAHs such as benzo(a)pyrene, together with back trajectory analysis suggested that the aerosols were aged and transported. PAHs, triterpane and sterane distributions provided evidence that coal burning was the main source of the continental outflow. The detection of levoglucosan and β-sitosterol in nearly all the samples showed the impact of biomass burning.     

Comparison of structural features of water-soluble organic matter from atmospheric aerosols with those of aquatic humic substances

Elemental analysis, Fourier transform infrared coupled to attenuated total reflectance (FTIR-ATR) and solid-state cross polarization with magic angle spinning-¹³C-nuclear magnetic resonance (CPMAS ¹³C NMR) spectroscopies were used to compare the chemical features of water-soluble organic compounds (WSOC) from atmospheric aerosols with those of aquatic humic and fulvic acids. The influence of different meteorological conditions on the structural composition of aerosol WSOC was also evaluated. Prior to the structural characterisation, the WSOC samples were separated into hydrophobic acids and hydrophilic acids fractions by using a XAD-8/XAD-4 isolation procedure. Results showed that WSOC hydrophobic acids are mostly aliphatic (40–62% of total NMR peak area), followed by oxygenated alkyls (15–21%) and carboxylic acid (5.4–13.4%) functional groups. Moreover, the aromatic content of aerosol WSOC samples collected between autumn and winter seasons is higher (∼18–19%) than that of samples collected during warmer periods (∼6–10%). The presence of aromatic signals typical of lignin-derived structures in samples collected during low-temperature conditions highlights the major contribution of wood burning processes in domestic fireplaces into the bulk chemical properties of WSOC from aerosols. According to our investigations, aerosol WSOC hydrophobic acids and aquatic fulvic and humic acids hold similar carbon functional groups; however, they differ in terms of the relative carbon distribution. Elemental analysis indicates that H and N contents of WSOC hydrophobic acids samples surpass those of aquatic fulvic and humic acids. In general, the obtained results suggest that WSOC hydrophobic acids have a higher aliphatic character and a lower degree of oxidation than those of standard fulvic and humic acids. The study here reported suggests that aquatic fulvic and humic acids may not be good models for WSOC from airborne particulate matter.     

铁炭复配修复地下水中NO_3~--N的条件研究

采用了铁炭复配修复地下水中NO3--N,探讨了实验条件对修复效果的影响。结果表明,在pH值近中性条件(初始pH 6.42)下,反应时间为1 h时NO3--N修复率达到60.85%;Fe/C=1∶1时介质最佳用量分别为4~5 g;Fe/C=1/1.5时修复率为72.80%;反应速率在高振荡强度下大于低振荡强度;氧化铜的催化效果最好,可使修复率提高7.5个百分点。铁炭复配介质修复地下水中NO3--N是有效可行的,修复率随反应时间的增加而提高,在Fe/C=1∶1时修复率与介质用量呈正相关,无限减小Fe/C比并不能无限提高修复率,振荡强度对修复具有显著影响,低振荡强度下的修复过程较高强度存在滞后现象,并非所有金属氧化物催化剂对铁炭修复NO3--N均有促进作用。     

出水口位置对垂直潜流人工湿地净化的影响

研究出水口位置对垂直潜流人工湿地净化的影响。垂直潜流人工湿地以间歇进水方式运行,进水水力负荷为0.125m3/(m2.d),进水来自南宁市琅东污水处理厂初沉池出水。研究结果表明,出水口位置对垂直潜流人工湿地净化有显著影响。与底部出水相比,中部出水的TN、SS和COD去除率分别提高了8.01%、8.48%、7.99%,出水NO-3-N质量浓度降低了9.38 mg/L;但NH+4-N去除率则降低了26.25%,TP去除率降低了21.21%。     

Inorganic and carbonaceous components in indoor/outdoor particulate matter in two residential houses in Oslo, Norway

A detailed analysis of indoor/outdoor physicochemical aerosol properties has been performed. Aerosol measurements were taken at two dwellings, one in the city center and the other in the suburbs of the Oslo metropolitan area, during summer/fall and winter/spring periods of 2002-2003. In this paper, emphasis is placed on the chemical characteristics (water-soluble ions and carbonaceous components) of fine (PM2.5) and coarse (PM2.5-10) particles and their indoor/outdoor relationship. Results demonstrate that the carbonaceous species were dominant in all fractions of the PM10 particles (cut off size: 0.09-11.31 microm) during all measurement periods, except winter 2003, when increased concentrations of water-soluble inorganic ions were predominant because of sea salt transport. The concentration of organic carbon was higher in the fine and coarse PM10 fractions indoors, whereas elemental carbon was higher indoors only in the coarse fraction. In regards to the carbonaceous species, local traffic and secondary organic aerosol formation were, probably, the main sources outdoors, whereas indoors combustion activities such as preparation of food, burning of candles, and cigarette smoking were the main sources. In contrast, the concentrations of water-soluble inorganic ions were higher outdoors than indoors. The variability of water-soluble inorganic ion concentrations outdoors was related to changes in emissions from local anthropogenic sources, long-range transport of particles, sea salt emissions, and resuspension of roadside and soil dusts. In the indoor environment the infiltration of the outdoor air indoors was the major source of inorganic ions.     

Redox activity of urban quasi-ultrafine particles from primary and secondary sources

To characterize the redox activity profiles of atmospheric aerosols from primary (traffic) and secondary photochemical sources, ambient quasi-ultrafine particles were collected near downtown Los Angeles in two different time periods – morning (6:00–9:00 PDT) and afternoon (11:00–14:00 PDT) in the summer of 2008. Detailed chemical analysis of the collected samples, including water-soluble elements, inorganic ions, organic species and water soluble organic carbon (WSOC) was conducted and redox activity of the samples was measured by two different assays: the dithiothreitol (DTT) and the macrophage reactive oxygen species (ROS) assays. Tracers of secondary photochemical reactions, such as sulfate and organic acids were higher (2.1 ± 0.6 times for sulfate, and up to 3 times for the organic acids) in the afternoon period. WSOC was also elevated by 2.5 ± 0.9 times in the afternoon period due to photo-oxidation of primary particles during atmospheric aging. Redox activity measured by the DTT assay was considerably higher for the samples collected during the afternoon; on the other hand, diurnal trends in the ROS-based activity were not consistent between the morning and afternoon periods. A linear regression between redox activity and various PM chemical constituents showed that the DTT assay was highly correlated with WSOC (R² = 0.80), while ROS activity was associated mostly with water soluble transition metals (Vanadium, Nickel and Cadmium; R² > 0.70). The DTT and ROS assays, which are based on the generation of different oxidizing species by chemical PM constituents, provide important information for elucidating the health risks related to PM exposure from different sources. Thus, both primary and secondary particles possess high redox activity; however, photochemical transformations of primary emissions with atmospheric aging enhance the toxicological potency of primary particles in terms of generating oxidative stress and leading to subsequent damage in cells.     

Seasonal characteristics of water-soluble organic carbon in atmospheric particles in the inland Kanto plain,Japan

An investigation of water-soluble organic carbon (WSOC) in atmospheric particles was conducted as an index of the formation of secondary organic aerosol (SOA) from April 2005 to March 2006 at Maebashi and Akagi located in the inland Kanto plain in Japan. Fine (<2.1 μm) and coarse (2.1–11 μm) particles were collected by using an Andersen low-volume air sampler, and WSOC, organic carbon (OC), elemental carbon (EC), and ionic components were measured. The mean mass concentrations of the fine particles were 22.2 and 10.5 μg m^?3 at Maebashi and Akagi, respectively. The WSOC in fine particles accounted for a large proportion (83%) of total WSOC. The concentration of fine WSOC ranged from 1.2 to 3.5 μg-C m^?3 at Maebashi, rising from summer to fall. At Akagi, it rose from spring to summer, associated with the southerly wind from urban areas. The WSOC/OC ratio increased in summer at both sites, but the ratio at Akagi was higher, which we attributed to differences in primary emissions and secondary formation between the sites. The fine WSOC concentration was significantly positively correlated with concentrations of SO₄^2?, EC, and K⁺, and we inferred that WSOC was produced by photochemical reaction and caused by the combustion of both fuel and biomass. We estimated that SOA accounted for 11–30% of the fine particle mass concentration in this study, suggesting that SOA is a significant year-round component in fine particles.