单颗粒-电感耦合等离子体质谱法测定地表水中金属纳米颗粒的初探

阐述了单颗粒电感耦合等离子体质谱法(SP-ICP-MS)的背景、分析原理、颗粒数量浓度和粒径计算原理,并采用该方法分析地表水中的纳米颗粒,探究其分析条件和影响因素。试验中测定了银、钛、铜、锌、镉、铅6种金属纳米颗粒(AgNPs、TiNPs、CuNPs、ZnNPs、CdNPs、PbNPs),纳米颗粒数量浓度为2.00×10^(3)~1.92×10^(6)个/mL。在粒径分布上,AgNPs和CdNPs相对单一且粒径较小,平均粒径为10和16 nm;其他4种纳米颗粒(TiNPs、CuNPs、ZnNPs和PbNPs)的粒径均在较广的范围内分布,粒径范围分别为58~176,43~75,90~278和19~136 nm。SP-ICP-MS方法相比其他分析方法更为便捷、快速、准确和全面,可同时获取纳米颗粒的粒径大小、分布状况,以及颗粒数量浓度和溶解态离子质量浓度等信息,可为之后的深入研究提供理论基础和科学依据。     

地表水中悬浮物含量和粒径对磷测定的影响

我国地表水体悬浮物含量和颗粒粒径组成的时空分异明显。该研究筛分3种粒径颗粒,研究不同粒径颗粒中赋存的磷形态及其解吸-吸附磷的能力特性差异,探讨不同悬浮物含量引起水体总磷(TP)测定结果偏差情况及改进建议。结果表明,粒径d<30 μm颗粒所赋存总磷、生物有效态磷含量明显高于50~150 μm、30~50 μm颗粒,水空白环境下粒径<30 μm颗粒所释放磷量也最高,等温吸附条件下粒径<30 μm颗粒具有更高的磷吸附能力。通过Freundlich交叉型吸附曲线拟合,粒径50~150 μm、30~50 μm、<30 μm颗粒的磷解吸-吸附平衡质量浓度分别为0.84、0.63、0.58 mg/L,粒径<30 μm颗粒在地表Ⅰ~Ⅴ类水体(TP≤0.4 mg/L)中更易达到磷解吸-吸附平衡状态。我国地表一般水体中悬浮物含量大多在零至几千mg/L范围,而使用 "静沉30min-消解" 国标前处理方法无法保证统一的沉降效果,使得水体TP含量测定结果偏低或偏高。针对地表一般水体,建议同时增加"混匀-消解-过滤"前处理方法测定水体TP含量作为参考。     

武汉地区沙尘天气气溶胶粒径分布特性研究

通过利用湖北省大气复合污染自动监控预警中心的振荡天平法颗粒物监测仪、光散射法气溶胶粒径谱仪,对武汉地区一次典型沙尘天气过程中记录的不同粒径气溶胶颗粒数量浓度、相对质量浓度进行研究。结果表明,在武汉地区沙尘天气过程中,粗颗粒显著增多,而细颗粒显著减少,这与部分研究发现的沙尘天气过程中粗颗粒与细颗粒共同显著增多的结论有所不同。粒径谱仪分析显示,大于PM5颗粒的增多对粗颗粒浓度增加有显著贡献,而小于PM0.5颗粒的减少则对细颗粒浓度降低有主要贡献,这可能是武汉地区沙尘天气过程颗粒物的变化特点。     

利用大气超级站对乌鲁木齐市一次沙尘天气过程及组份的分析

本研究利用大气超级站对乌鲁木齐市4月9日至10日沙尘天气过程,粒径谱、离子和重金属组成及变化进行分析.研究结果表明激光雷达观测结果与环境空气质量监测基本一致;小粒径颗粒在沙尘和非沙尘时段含量最多,但在沙尘时段大粒径颗粒的增长幅度远大于小粒径;沙尘过程中的离子主要来源于土壤一次源;沙尘过程中地壳元素浓度及占比均显著升高,...     

西宁市典型开放源颗粒物粒径组成特征分析

采用BT-9300S激光粒度仪分析了西宁市道路尘、扬尘、土壤尘、建筑尘4种典型开放源的粒径组成。结果表明,4种类型尘中大粒径颗粒物占主导地位,粒径大于10 μm颗粒占到全部颗粒的73.80%以上,可吸入颗粒物的含量仅占7.06%～26.20%;建筑尘的细颗粒物含量最高,粒径小于2.5、1 μm的颗粒含量分别为8.36%±4.25%、2.42%±1.02%;道路尘的细颗粒物含量最低,粒径小于2.5、1 μm的颗粒含量分别为2.30%±0.94%、0.73%±0.28%;4种类型尘的体积平均直径、面积平均直径、中位直径分别在37.70～87.99 μm、8.50～23.53 μm、28.95～74.98 μm之间,其中道路尘的3种粒径参数最大,建筑尘最小;开放源颗粒物的粒度分布曲线主要呈头长尾短的不对称单峰分布,累积频率曲线为两段式,存在较为明显的拐点。     

乌鲁木齐城市土壤与灰尘粒径空间分布特征

结合野外调研的基础,按照四分法采集乌鲁木齐市城市土壤与城市灰尘样品共计306个,利用激光粒度仪和ArcGIS分析了城市土壤与灰尘样品的全粒径(0.02～2 000μm)组成与空间分布特征。研究结果表明:乌鲁木齐城市土壤与灰尘在小粒径范围内空间分布差异不明显,城市土壤粒径主要集中在10～50μm,城市灰尘集中于100～250μm;城市重工业对城市土壤和灰尘小粒径颗粒分布影响更大,而城市商业、居住等为主的人类其他活动行为对大粒径颗粒影响更为显著。乌鲁木齐城市土壤可能对城市灰尘PM_1、PM_(2.5)、PM_(10)粒径分布的贡献比较突出,应从城市土壤、城市灰尘、颗粒物粒径空间分布、气象等因素综合考虑乌鲁木齐市大气污染的防控。     

保山市大气细颗粒物排放特征与理化特征分析

于2016年11月9日—14日,用单颗粒气溶胶在线源解析技术分析保山市体育馆监测点大气中PM_(2.5)的化学组成、粒径分布、来源及典型排放源质谱特征。结果表明:采集的颗粒可分为7类,主要以有机碳、元素碳和混合碳颗粒为主,占电离颗粒数的60%以上;不同类型颗粒粒径分布差异较为明显;机动车尾气为首要污染贡献源,且呈周期性变化,每日有两个上升时段,分别为凌晨1:00—10:00和12:00—20:00;其次为燃煤源,贡献率为10%～40%;工艺过程源与生物质燃烧源贡献率相一致,总体上夜间贡献率高于白天;扬尘源、二次无机源贡献率变化幅度不大。     

桂林市细颗粒物部分典型排放源的粒径谱及成分分析

采用在线单颗粒气溶胶质谱技术源解析方法,对桂林市PM2.5典型排放源的粒径和化学成分进行质谱分析,采集燃煤/燃气源、工业工艺源、扬尘源、油烟源4类共计7个典型排放源。结果表明,桂林市4类排放源细颗粒物的粒径分布为0.25~1.25μm,80%以上的细颗粒分布在0.2~1.0μm的小粒径范围,峰值约0.68μm。细颗粒物离子成分含有Na~+、Mg~+、K~+、NH~+4、Fe~+、Pb~+、Cd~+、V~+、Mn~+、Li~+、Al~+、Ca~+、Cu~+、Zn~+、Cr~+、CN~-、PO_3~-、NO_2~-、NO_3~-、Cl~-、SO_4~(2-)、SiO_3~-等成分,桂林市细颗粒物为元素碳、有机碳元素碳、有机碳、富锰颗粒、富铁颗粒、富钾颗粒、矿物质、左旋葡聚糖以及其他金属等9类。     

北京地区PM10与秸秆燃烧排放单颗粒对比分析

采用场发射带能谱扫描电镜(FESEM/EDS)法分析北京怀柔地区PM10与秸秆燃烧排放颗粒的形貌特征和成分差异.结果显示:秸秆燃烧后排放颗粒物多为大粒径颗粒,成分上都含S、Cl和K元素.含有生物质燃烧标志元素K的PM10颗粒物多为含Si、Al和Na元素的燃煤飞灰和矿物颗粒,与秸秆燃烧排放颗粒组成化学元素差异明显.据此推...     

东平湖不同粒径底泥沉积物中汞的形态分布

对东平湖底泥沉积物中重金属汞的总量和形态及沉积物形貌进行了研究.从粒径分布与沿程分布分析了汞元素的形态分布特征.结果表明,东平湖底泥沉积物的主要粒径<63μm,且沉积物颗粒粒径越小,其表面的吸附物越多.不同粒级沉积物中汞的存在均以可氧化提取态形式为主,汞的形态分布与沉积物粒径的相关性可能受到原生矿物及因粒度效应产生吸附差异的综合影响.汞形态的沿程分布特征表明,湖南采样点受污染严重,潜在危害较大.     

采样时间对ANDERSEN采样器采样效果的影响

在室内用ANDERSEN生物粒子采样器进行了不同采样时间对采集空气细菌和真菌粒子浓度，粒数中值直径效果的研究，结果表明，在1－12min内，采集的空气细菌和真菌粒子浓度随采样时间的增加而减少，呈明显的负相关关系，相关系数分别为－0．903和－0．688，P值均大于0．05，另外，在采样过程中，空气真菌比细菌耐受采样空气冲击力的能力强，采样时间对空气细菌和真菌粒子的粒度分布和粒数中值直径的影响不明显。     

The effect of wind direction on the observed size distribution of particle adsorbed polycyclic aromatic hydrocarbons on an inner city sampling site

An investigation of the variability in the size distribution of particle adsorbed polycyclic aromatic hydrocarbons (PAHs) on an inner city sampling site showed differences depending on the wind direction. Particle size distributions of PAHs from outdoor air sampling were measured in Munich from 1994 to 1997. The sampling site is located northeast of a crossing with heavy traffic and southwest of a large inner city park. Depending on the wind direction, three different size distributions of particle adsorbed PAHs were observed. The maximum PAH concentration on very small particles (geometric mean diameter 75 nm) was observed with wind from west to southwest coming directly from the crossing area or the roads with heavy traffic. The maximum PAH concentration on particles with geometric mean diameter of 260 nm was found on days with wind from the built-up area north of the sampling site. On particles with geometric mean diameter of 920 nm the maximum PAH concentration was found on days with main wind directions from northeast to east. On these days the wind is blowing from the direction of the city park nearby. The distribution of particle adsorbed PAHs within different particle size classes is substantially influenced by the distance of the sampling site from strong sources of PAH loaded particulate matter.     

Evaluation of acoustical particle counter for the sizing of fog droplets

An acoustical particle counter (or acoustical particle sizing device) was evaluated for counting and sizing of fog droplets. Fog droplets were generated under controlled conditions in the laboratory. Fog droplet sizes were measured by an optical and an electron microscope and compared to results from the acoustical particle counter. Most of the droplets were found to be in the size range of 5–30 µm. The mean diameters estimated from the acoustical particle counter were in agreement with the microscope values of mean droplet diameter. A Rich 100 condensation nuclei monitor was also operated simultaneously during the fog droplet counting to monitor the condensation nuclei counts in the laboratory. The results indicate that condensation nuclei count is inversely correlated with the fog droplet threshold diameter. Aerosols of uniform size (35 µm) were generated by the vibrating orifice monodisperse aerosol generator and counted at three different flow rates by the acoustical particle counter. The counts/liter/minute were similar, indicating the reliability of the acoustical particle counter.     

Colloidal mercury (Hg) distribution in soil samples by sedimentation field-flow fractionation coupled to mercury cold vapour generation atomic absorption spectroscopy

Diverse analytical techniques are available to determine the particle size distribution of potentially toxic elements in matrices of environmental interest such as soil, sediments, freshwater and groundwater. However, a single technique is often not exhaustive enough to determine both particle size distribution and element concentration. In the present work, the investigation of mercury in soil samples collected from a polluted industrial site was performed by using a new analytical approach which makes use of sedimentation field-flow fractionation (SdFFF) coupled to cold vapour generation electrothermal atomic absorption spectroscopy (CV-ETAAS). The Hg concentration in the SdFFF fractions revealed a broad distribution from about 0.1 to 1 μm, roughly following the particle size distributions, presenting a maximum at about 400-700 nm in diameter. A correlation between the concentration of Hg in the colloidal fraction and organic matter (O.M.) content in the soil samples was also found. However, this correlation is less likely to be related to Hg sorption to soil O.M. but rather to the presence of colloidal mercuric sulfide particles whose size is probably controlled by the occurrence of dissolved O.M. The presence of O.M. could have prevented the aggregation of smaller particles, leading to an accumulation of mercuric sulfides in the colloidal fraction. In this respect, particle size distribution of soil samples can help to understand the role played by colloidal particles in mobilising mercury (also as insoluble compounds) and provide a significant contribution in determining the environmental impact of this toxic element.     

Analysis for Chemical Characterization of Atmospheric Aerosols Application of X-ray Microprobe System and Double Thin Film Method

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements. Double thin film method was applied to investigate the seasonal change of the mixing states of single sea-salt aerosols associated with chlorine loss due to the heterogeneous reactions between sea-salt particles and acidic gases. It was revealed that the percentages of both chloride-nitrate mixed particles and sulfate-nitrate ones were larger in wintertime than those in summertime and fraction of chloride-nitrate mixed particles increased with an increase of particle size. Comparison between the size-segregated bulk analysis and the single particle analysis demonstrated that remarkable chloride depletion occurred in coarse particles sampled on May in the former analysis, while chloride depletion in coarse particles was not marked in the latter analysis. The discrepancy attributes to the difference of the sampling time between both analyses because significant change of air mass route occurred during the bulk sampling after completion of the single particle sampling.     

氯化钡浸提法测定土壤可交换酸度

建立了氯化钡浸提测定酸性土壤可交换酸度的方法,优化了水土比、土壤粒度、浸提液质量浓度、浸提次数、震荡时间等试验参数。方法检出限为0．016cmol／kg,经重复性和再现性检验表明精密度良好。该方法可同时用于土壤可交换性氢和可交换性铝的测定。     

重庆城区不同粒径颗粒物元素组分研究及来源识别

为研究重庆市大气颗粒物的污染特征及其来源,于2010年3—10月在主城区分别采集PM_1.0、PM_2.5和PM₁₀3种粒径的颗粒物样品,利用XRF分析其中的26种元素浓度。结果表明,重庆市主城区S元素在各粒径中含量都较高,细粒子中K的含量较高,粗粒子中Si、Ca和Fe的浓度较大。富集因子分析表明,主城区Cd、S、Se等污染元素的富集系数较大,且粒径越小,富集现象越明显。利用因子分析得出土壤风沙、扬尘、燃煤的燃烧、机动车燃油产生的尾气排放、生物质燃烧排放是重庆市颗粒物污染的主要来源。     

Characterization of thermally generated aerosols from polyurethane foam

Isocyanates constitute a group of highly reactive chemicals used on a large scale for the production of flexible polyurethane (PUR) foam. Exposure to isocyanates is known to produce irritation of the mucous membranes and the eyes. Isocyanates also have strong sensitizing properties and may cause occupational asthma. It is therefore important to monitor isocyanate emissions at workplaces. To obtain information for the improvement of isocyanate samplers and for health risk assessments of exposure, the emitted aerosol from two types of flexible PUR foam subjected to thermal degradation was characterized. Particle size distribution and toluene diisocyanate (TDI) concentration in the emitted aerosols were measured. Thermal degradation of flexible PUR foam at temperatures from 250 to 300 degrees C produced an aerosol with a geometric mean particle diameter of 30-50 nm. Between 5% and 9% of the PUR foam was emitted as TDI, and 2% to 6% of TDI monomers were found in the particle phase under the experimental conditions used. The 2,6-TDI isomer was more abundant in the gas phase than in the particle phase.     

A comprehensive method for aeolian particle granulometry and micromorphology analyses

The aim of this study was to use a new approach to investigate aeolian particle granulometry and micromorphology. Taking total aeolian deposition into account, we used parameters such as, particle area, perimeter, shape analysis for particle roughness (area/perimeter) and elongation (long/short axis). These parameters were analyzed on temporal and spatial scales at four study sites in the eastern Negev Desert, Israel. The total collection of particles was sorted into three size groups based on particle area to facilitate comparison. The classic definition of particle size (equating particle length with particle diameter) produced relatively small variations among the three size classes (25-38.6%). Our proposed comprehensive method demonstrated significant variation among the three size classes (13.9-60.8%), e.g. the classic method placed 36.4% of the particles in size class two while the new method placed 60.8% of the particles in this size class; the differences were even more significant regarding size class 3 (38.6% vs. 13.9%, respectively). The classic method did not facilitate investigation of particle roughness and elongation. With this new approach, it was possible to clearly define the particles by size class, based on these characteristics. With roughness, the variation among size classes 2 and 3 was about 27%. With elongation, the variation among size classes two and three was about 21%. Applying similar investigation method to study the aeolian particle granulometry and micromorphology can better facilitate more detailed calculation of particle size distribution, roughness and elongation.     

Workplace aerosol mass concentration measurement using optical particle counters

Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM? 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO?) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions calculated from the OPC data are closely correlated with the results of the particle size-selective sampling using the CIP 10. Furthermore, the OPC data allow calculation of the thoracic fraction of workplace aerosol (not measured by sampling), which is interesting in the presence of allergenic particles like fungi spores. The results also show that the modified COP inlet adequately samples inhalable aerosol in the range of workplace particle-size distribution.