电感耦合等离子体质谱法测定PM2.5中的重金属元素

采集环境空气细颗粒物(PM2.5)样品,建立了电感耦合等离子体质谱法(ICP-MS)同时测定PM2.5中10种重金属元素的方法。样品经5%HNO_3超声浸提,过滤后,用ICP-MS测定。结果表明:10种重金属元素的检出限在0.030μg/L~0.13μg/L之间;线性关系良好,精密度为0.82%~4.3%,回收率为80.1%~113.0%。该方法快速、准确,可用于PM2.5中重金属元素的测定。     

北京大气颗粒物PM10和PM2.5中水溶性阴离子的组成及特征

利用离子色谱技术对北京PM10和PM2.5中的水溶性阴离子（F^-,Cl^-,NO3^-和SO4^2-）进行了分析测定,并讨论了它们的分布、浓度变化和来源.F^-,Cl^-,NO3^-和SO4^2-离子的总质量分别占PM10和PM2.5总量的18.2%和24.2%,是大气颗粒物的重要组分.其中F^-主要存在于PM10的粗颗粒中,而Cl^-,NO3^-和SO4^2-则主要在细颗粒中富集.PM10和PM2.5中Cl^-在总氯中所占的比例分别达到了49.5%和40.3%,并与总氯具有非常好的相关性.氯在大气中明显富集,其主要的人为来源为煤的燃烧.SO4^2-和NO3^-具有比较好的相关性,其浓度在7月份最高,9、10月较低,进入冬季采暖期之后浓度升高.在PM10和PM2.5中NO3^-与SO4^2-的质量之比分别在0.1～0.6和0.1～0.5之间,说明燃煤对它们的贡献要大于汽车尾气.     

Assessment of trace elements characteristics and human health risk of exposure to ambient PM2.5 in Hangzhou,China

A method for simultaneously determining the trace elements in particulate matter (PM) (PM2.5) by inductively coupled plasma mass spectrometry was established. The PM2.5-loaded filter samples were digested under the optimised conditions including a mixture of HNO₃–HCl–HF with ultrasonication proceeding at 70°C for 2 h. Recoveries of 90.83–103.33% were achieved for 20 elements (Co, Sr, Ag, Cd, Sb, La, Ce, Sm, W etc.) in NIST standard reference material 1648a (urban PM). PM2.5 samples were collected at urban site in Hangzhou from August 2015 to November 2015. PM2.5 concentrations of 15% sampling days exceeded the daily limitation and the mean concentrations of PM2.5 from August to November reached the 66.4% of the limitation. PM2.5 concentrations in summer were higher than that in autumn. The concentration of Zn was highest, following with Al, Pb, Mn, Cu and As. Significant enrichment was observed in Mn, Zn, Pb, Ag, V, Ni, Cu, As, Se, Hg, Co, Cd and W, which was probably induced by vehicular exhaust, oil and residual fuel combustion and industrial emissions. The daily mass concentrations of PM2.5 and elements fluctuated significantly. Rainfall could significantly reduce the concentration of Ti, Mn, Cu, Zn, As, Se, Hg, Sr, Ag, Cd, Sb, La, Ce, Sm and Pb, and the risk levels of carcinogenic elements and non-carcinogenic elements in rain day were significantly lower (43.7–81.4%) than those in non-rain day. The risk levels of Co, Cd and As could lead to adverse health outcomes through the respiratory system, which should deserve more attention, while the risk levels of Ni and non-carcinogenic elements (Hg, Mn, Cu, Zn, Pb, V) were under average risk acceptance.     

杭州市冬季大气气溶胶PM2.5中二恶英和多氯联苯的污染特征

2014年1月在杭州市选择5个点位采集大气颗粒物PM_2.5样品,采用同位素稀释高分辨气相色谱/高分辨质谱测定PM_2.5中的二恶英（PCDD/Fs）和多氯联苯（PCBs）,对PM_2.5的污染状况以及PM_2.5中PCDD/Fs和PCBs的污染水平及分布特征进行了研究。PM_2.5的质量浓度范围为85~168 μg/m³,PM_2.5污染较重,但与2004年同期相比明显降低。PM_2.5中PCDD/Fs的毒性当量（TEQ）为0.277~0.488 pg I-TEQ/m³,明显高于2004年同期采集样品。颗粒物中PCDD/Fs以八氯代二苯并-对-二恶英（OCDD）为主,毒性当量主要贡献者为2,3,4,7,8-五氯代二苯并呋喃（2,3,4,7,8-PeCDF）。PM_2.5中PCBs的质量浓度范围为2.9~8.1 pg/m³,二恶英类多氯联苯（DL-PCBs）的毒性当量范围为2.6~6.1 fg WHO-TEQ/m³,污染较低。PCBs在颗粒物中分布以PCB-28为主,但对毒性当量贡献最大的为PCB-126。PCDD/Fs和PCBs的气-固分配特征表现为PCDD/Fs主要分布于颗粒物中,而PCBs主要分布于气相中。     

微波消解–原子荧光法同时测定PM2.5中砷、汞含量

采用微波消解–原子荧光法测定PM2.5中砷、汞含量。实验结果表明,当还原剂硼氢化钾的质量分数为2%、溶液介质酸度为4%(体积分数)盐酸时,同时测定砷、汞可获得最佳的荧光值。砷、汞测定的检出限分别为0.027,0.006μg/L,空白滤膜的加标回收率分别为95.3%~101.7%,96.0%~106.0%,样品的加标回收率分别为95.0%~103.5%,93.3%~110.0%。该法检出限低,准确度高,适用于环境空气PM2.5中砷、汞含量的测定。     

校园室内外大气PM2.5中的含碳气溶胶及室内源特征

分夏、冬季采集南昌大学前湖校区室外和3个不同室内环境中的PM2.5,测定有机碳(OC)和元素碳(EC),并分析室内、外碳气溶胶质量浓度及其分布特征;利用OC-EC关系式半定量分析室内排放源;结合室内、外二次有机碳(SOC)和SOC/OC的分布进一步讨论不同室内排放源的特征及对SOC的影响;对4个采样点的8个碳组分丰度特征比较分析,结果表明复印/打印机对室内OC的贡献高,8个碳组分的丰度分布特征与其它排放源具有较明显的差异。     

离子色谱法测定PM_(2.5)中可溶性阴离子含量不确定度评议

准确测定大气颗粒物中水溶性组分对分析污染物来源及身体健康具有重要意义。本文采用离子色谱法测定PM2.5中水溶性阴离子(氯离子、硝酸根离子、硫酸根离子)含量,并对测定的不确定度进行分析。分析过程不确定度来源是样品重复性测量引入不确定度,样品测量准确性引入不确定度和标准曲线的不确定度。应用不确定度评定理论,分别计算氯离子、硝酸根离子和硫酸根离子的合成不确定度。结果表明,滤膜质量与取样环节是不确定度的主要来源。为了提高分析准确性,建议使用本底低的滤膜,取全样分析。     

上海市区大气颗粒物(PM2.5)中铅、镉的分析测定和污染特征研究

以石英超细纤维滤膜采集上海市长宁区的大气颗粒物(PM2.5)样品,采用球磨机将滤膜研磨成细微颗粒,并以0.7％ Triton X-100作为分散剂,制备了稳定均一悬浮液,建立了一种简便、绿色、快速的悬浮液进样-石墨炉原子吸收法测定PM2.5中铅和镉的方法.铅在0.1～75 μg/L范围内,镉在0.2～3 μg/L范围内,校正曲线的线性相关性大于0.998;铅和镉的检出限分别为0.36和0.06 μg/L,相对标准偏差小于5％.采用HF-HN03体系酸消解样品,并与电感耦合等离子体质谱法和石墨炉原子吸收光谱法测试结果对比,验证了方法的准确性.采用本方法对2014年11月～ 2015年5月期间上海市区大气中PM2.5及铅和镉的污染特性进行分析,结果表明,铅和镉的质量浓度随时间变化趋势与PM2.5的质量浓度随时间的变化趋势呈现良好的一致性.     

广州市夏、冬季室内外PM2.5中元素组分的特征与来源

通过采集广州市9个居民住宅室内、外的PM2.5样品,测定分析PM2.5中18个元素组分的质量浓度,分析讨论其污染、分布特征并解析其污染来源。经过比较得知,广州市PM2.5中元素污染较严重;不同类型住宅PM2.5中元素浓度存在空间分布特征;大部分元素浓度具有夏季比冬季低的变化特征;室内与室外元素浓度比值介于0.4974～2.0497之间;元素浓度的室内、室外相关拟合结果说明冬季室内空气受室外空气影响比夏季时情况更明显;基于富集因子分析,Se、As、S、Pb、Br、Zn和Cl元素高度富集;Ni、V、Cu元素中等富集,主要来自人为源,而Cr、Sr、K、Mn、Ca和Ti元素不富集,主要来自自然源。     

Pollution characteristics of atmospheric fine particles and their secondary components in the atmosphere of Shenzhen in summer and in winter

Two field measurements for atmospheric fine particles were conducted in Baoan district of Shenzhen during the summer and winter in 2004. Totally 30 sets of 24 h samples were collected, and then the mass concentrations and chemical compositions were determined. The seasonal varia- tions and secondary pollution characteristics of fine particles during the sampling periods were dis-cussed with meteorological factors. The results show that seasonal variations of atmospheric particles are significant in Shenzhen. The average mass concentrations of PM2.5 and PM10 in summer were 35 μg·m-3 and 57 μg·m-3, respectively, and those in winter were 99 μg·m-3 and 135 μg·m-3, respec-tively. The concentrations of both PM2.5 and PM10 in winter increased 184% and 137%, respectively, compared to those in summer. PM2.5 accounted for 61% and 75% of PM10 in summer and in winter, respectively, indicating severe fine particle pollution in Shenzhen. During the summer and winter sampling periods, the mean OC/EC ratios were 3.4 and 1.6, respectively. The estimated secondary organic carbon (SOC) averagely accounted for 56% and 6% of the total OC in summer and in winter, respectively, which implies a major contribution of SOC to OC in summer. During the continuous high temperature period in summer, both the concentrations and fractions of secondary aerosol compo-nents in PM2.5 were highly elevated, suggesting severe secondary pollution again. The prevailing wind was from South China Sea in summer, and the air quality was good. The prevailing wind in winter was from Mainland China to the north, and the polluted air mass led to poor air quality.     

雾霾之PM2.5的来源、成分、形成及危害

介绍雾霾及PM2.5的基本知识,从化学角度讨论PM2.5的来源、成分、形成和危害;阐述发展PM2.5分析新方法对于掌握其危害,研究其生理影响和找到其源头的重要意义.清洁能源的高效利用,排放物的后处理以及“碳交易”等有希望成为解决雾霾及PM2.5问题的突破口.     

离子色谱法同时测定PM2.5中的5种阳离子和3种有机胺

建立一种离子色谱检测PM2.5中阳离子和有机胺的方法。采用Thermo Fisher Ion Pac CS17和CG17色谱柱,以甲基磺酸为淋洗液,梯度洗脱,30 min内进行分离测定,Na+,K+,NH4+,Mg2+,Ca2+5种阳离子和丙胺、二甲胺、三甲胺的色谱峰面积与其质量浓度具有良好的线性,相关系数r2在0.998 1和0.999 8之间,各成分检出限为0.02~0.16μg/L,色谱峰面积的精密度在0.7%~1.9%(n=7)之间,加标回收率为88.6%~95.6%。该方法可用于评价区域大气污染状况及污染物来源。     

美国PM2.5采样器校准方法总结

介绍美国PM2.5采样器的分类,从采样时间、滤膜称量、流量、温湿度要求和采样器性能指标等方面总结了美国PM2.5联邦参考方法采样器的校准方法。介绍美国PM2.5联邦等效方法采样器的分类及3个等级PM2.5联邦等效方法采样器的不同校准方法,以及PM2.5单分散气溶胶两种常用制备方法的制备步骤,以期促进完善我国PM2.5监测仪量值溯源体系。     

离子色谱-电感耦合等离子体质谱联用测定大气颗粒物PM2.5和PM10中的六价铬

建立了大气颗粒物PM_2.5、PM₁₀中六价铬（Cr（Ⅵ））的离子色谱-电感耦合等离子体质谱（IC-ICP-MS）检测方法。采用碳酸氢钠（NaHCO₃）溶液超声提取大气颗粒物样品中的Cr（Ⅵ）,并使用含有0.22 g/L 乙二胺四乙酸二钠盐（Na₂EDTA）的75 mmol/L硝酸铵溶液（pH 7.0）淋洗液通过离子色谱柱（AG7,50 mm×4 mm）分离出样品中的Cr（Ⅵ）,电感耦合等离子体质谱测定。标准溶液中Cr（Ⅵ）的质量浓度在0.05~5 μg/L范围内呈良好的线性关系,相关系数达0.9999,标准溶液测定的精密度为1.0%~4.0%,标准样品测定的相对误差为3.3%;纤维素滤膜适用于Cr（Ⅵ）的采样,将纤维素滤膜碱化后,Cr（Ⅵ）的回收率从75%增加到102%;样品在20 mmol/L碳酸氢钠溶液中超声30 min后上机测试,提取完全且回收率稳定;当采样体积为20 m³,方法的检出限为0.0004 ng/m³;采集并测定了PM_2.5及PM₁₀实际样品,样品的加标回收率为91.6%~102%,精密度为1.7%~7.6%。该方法高效、稳定、灵敏,适用于大气颗粒物中六价铬的测定。     

南昌市PM_(2.5)中硫酸盐、硝酸盐及其气态前体物的分布特征与转化机制

2014年1月至2015年1月,在南昌市3种类型采样点(混合区、主干道旁侧、燃煤电厂附近),对大气PM_(2.5)中SO_4~(2-)和NO_3~-及其气体前体物SO_2、NO_2进行同步采样,通过分析硫氧化速率(SOR)和氮氧化速率(NOR),对PM_(2.5)中硫酸盐和硝酸盐的来源、形成机制和影响因素进行探讨。结果表明,南昌市SO_2浓度18.9~74.8μg/m~3,NO_2浓度29.7~62.6μg/m~3,PM_(2.5)中SO_4~(2-)浓度13.7~28.4μg/m~3,NO_3~-浓度3.9~39.9μg/m~3,SOR值0.28~0.60,NOR值0.09~0.33。SO_2、NO_2、SO_4~(2-)、NO_3~-和SOR、NOR的季节分布和日分布,反映硫酸盐和硝酸盐的二次生成受气象条件、环境条件和排放源的影响。SOR与NOR的季节分布正好相反,日分布也差异较大,反映生成机制不同。SO_2、NO_2、SO_4~(2-)、NO_3~-和SOR、NOR在不同采样点的分布,反映燃煤烟气和机动车尾气增加SO_2、NO_2的浓度,促进SO_4~(2-)、NO_3~-的二次生成。[NO_3~-]/[SO_4~(2-)]春、夏、秋、冬分别为0.86、0.15、0.83、0.70,反映南昌市机动车尾气贡献比例较大;[NO_3~-]/[SO_4~(2-)]受硫酸盐和硝酸盐在不同季节的二次生成机制和速率的影响,也受排放源的影响。     

广州大气细粒子中有机碳、元素碳和水溶性有机碳的分布特征

在广州市中山大学采样点进行了为期1年的大气细粒子(PM2.5)采样,监测分析得到PM2.5及有机碳(OC)、元素碳(EC)和水溶性有机碳(WSOC)等组分的质量浓度,并进行了比较和评价分析。结果表明广州市细粒子碳污染较严重。对OC、EC和WSOC质量浓度的月变化和季节变化特征进行了讨论,并分析了原因。OC、EC浓度相关性好,表明OC、EC来源大部分相同。根据OC/EC比值,估算二次有机碳(SOC)量,结果是SOC占OC的1/3。讨论了SOC和SOC/OC比值的季节分布,结果证明SOC夏季生成比冬季多。     

Determination of polycyclic aromatic hydrocarbons (PAHs) in particulate matter collected with low volume samplers

The determination of polycyclic aromatic hydrocarbons (PAHs) contained in samples of particulate matter (PM), collected with low volume pumps, were carried out with an high sensitivity method that comes from several revisions of a previous method. The present work describes how, by using programmable temperature vaporization (PTV) and a mass selective detector with inert ionic source for the GC-MS analysis and the modifications of microwave-assisted extraction (MAE), the sensitivity of the method can be increased.The PAHs chosen for testing the method are: benzo[a]anthracene (BaA), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (Ip) and dibenzo[a,h]anthracene (DbA). They, in fact, belong to that group of substances that are the most harmful for human health for their carcinogenicity.PAHs recoveries for spiked standard solutions at different concentrations were between 95 and 100% with relative standard deviation ranging from 1 to 3%. The revised method was validated using a 1649a urban dust standard reference material (SRM). The results obtained were in good agreement with certified values. The high sensitivity of the method allows to carry out analyses using only a half of the sampled filter (usually 47 mm diameter membranes). In this way, the other half can be used for the characterization of the other components of PM (heavy metals, organic carbon, ions, etc). The last step has been constituted by application of the optimized method on real samples collected in two cities located in Southern Italy (Bari and Taranto).     

智能石墨消解–ICP–MS法测定空气PM2.5中的Pb和Cd

建立电感耦合等离子体质谱(ICP–MS)测定空气PM2.5中的Pb和Cd元素的分析方法。采用连续β射线–DHS PM2.5大气颗粒物浓度监测仪采集空气中的PM2.5,以智能石墨消解PM2.5滤膜样品,ICP–MS测定其中的Pb和Cd元素含量。在优化的仪器条件下,元素Pb和Cd标准曲线的线性相关系数均为0.999 9,检出限分别为0.018,0.52ng/m3,满足HJ 657–2013的要求。Pb和Cd的加标回收率分别为95.8%~101.4%,99.3%~104.9%,测定结果的相对标准偏差分别为4.20%和2.38%(n=6)。对滤膜标准样品进行了测定,测定结果与标准值一致。该方法测定结果准确、可靠,可用于测定空气PM2.5中的Pb和Cd。     

秸秆燃烧排放PM2.5特征及影响因素研究

生物质燃烧向大气中排放大量颗粒污染物, 在中国, 收获季节大量秸秆被直接露天燃烧处理, 对区域环境质量和人体健康造成严重影响. 对我国最主要的两种粮食作物玉米和小麦秸秆的露天燃烧进行模拟, 分析颗粒物排放水平, 特征及影响因素. 玉米和小麦秸秆燃烧PM_2.5排放因子分别为1082.8和835.7~897.3 mg/kg. 有机物是颗粒物最主要组分, 总量占PM_2.5质量的42%~66%. Cl^-和K⁺分别占PM_2.5总质量的4%~15%和2%~14%, K⁺/EC值为0.5~3.8. 各物种在颗粒物中所占比例与之前研究结果一致. 秸秆含水量和燃烧温度影响PM_2.5排放水平和组成特征. 随秸秆含水量增加, PM_2.5和OC的排放因子增加; 秸秆含水量增加, 燃烧温度逐渐降低, 由生物质燃料释放进入烟气中的K⁺和Cl^-比例逐渐减小导致二者在颗粒物中的比例降低. 我国每年由玉米和小麦秸秆露天燃烧排放的PM_2.5和OC分别为92.7 Gg和47.5 Gg, 在总量中占重要比例.     

不同酸体系对PM2.5中重金属测定的影响

采用3种消解体系对聚四氟乙烯滤膜采集的PM2.5样品进行消解,利用电感耦合等离子体质谱法测定样品中15种重金属元素。比较了硝酸–盐酸(A)、硝酸–过氧化氢(B)、硝酸–氢氟酸–高氯酸(C)3种体系的消解效果,分析了南京市PM2.5中重金属含量,并与文献值进行了比较。结果表明,A,B,C 3种体系测定结果的相对标准偏差的平均值分别为7.9%,9.9%和17.2%,加标回收率分别为80.5%~111.0%,87.5%~120.0%,74.1%~113.0%。C体系测定结果偏高,操作步骤繁琐,精密度差;A,B体系具有试剂用量少,精密度好,准确度高等优点,能满足环境空气PM2.5中多元素同时测定的要求。