济南市大气颗粒物来源解析样品的采集及处理技术

本文主要研究了济南市大气颗粒物来源解析中样品的采集及处理技术。通过对济南市大气颗粒物污染源的深入调查，确定排放源类的类别为土壤风沙尘、工业燃煤（油）飞灰、民用燃煤（油）飞灰、机动车尾气燃油飞灰、建筑水泥尘、钢铁尘、扬尘排放源类。根据各种排放源类的不同，须采取不同的采样方式和处理技术，确保样品的代表性和样品分析的最佳效果，同时对颗粒物污染源排放的季节性和季节稳定性作了特征分析。通过受体样品和源样品的粒度分散度测量及数据处理的结果得出尘粒在空气中的沉降和扩散情况，为空气中粗、细颗粒物的组成提供科学依据。为颗粒物来源解析的研究奠定了成功的基础。     

北京地区冬季气溶胶分级化学成分及来源分析

在北京城区进行冬季大气气溶胶采样,样品采用PIXE方法进行分析,得到大气气溶胶中20种元素的质量浓度。结果表明:元素Mg、Fe、Si这3种元素均呈粗粒模态单峰型分布,且峰值出现在2～4μm,表明它们来自土壤尘;S、Cl、K等3种元素谱分布呈细粒单峰型分布,峰值都出现在0.25～0.5μm范围内,表明这3种元素主要来自燃煤;Cu、Zn、As、Br、Pb等5种元素谱分布呈双峰型谱分布;Ni、Cu、Zn、As、Se、Br、Pb等元素的粗、细模态的富集因子都较大,尤其是细粒模态,表明这些元素更容易在细粒模态上富集,进一步说明这些元素主要来自人为污染源。因子分析结果表明:土壤尘、煤烟尘、工业源和汽车尾气排放源对北京冬季气溶胶有主要贡献。     

西安市餐饮业大气颗粒物浓度与碳气溶胶研究

为了了解西安市餐饮业大气颗粒物浓度和分布特征,利用安德森8级撞击采样器采集6家不同餐馆颗粒物样品,并用热光碳分析仪对其中的碳气溶胶进行了分析。结果表明:6家餐馆中,面庄、火锅店和韩国菜馆中颗粒物质量浓度较大,烤肉店中有机碳质量浓度最大,并且有机碳与PM1.1的质量浓度比值为99%,其他烹饪方式的有机碳占颗粒物的比例小于20%;餐馆室内大气颗粒物粒径分布呈双峰模式,主峰集中在小于1.1μm范围内,以PM1.1为主;有机碳粒径分布呈单峰模式,集中在0.43~0.65μm范围内。     

实测数据对大气颗粒物浓度计算模式的验证

针对常用的大气颗粒物(PM10、PM2.5)浓度计算模式计算结果偏差较大的问题,由太原市城区例行监测的PM10浓度估算出燃煤电厂导致的大气颗粒物(PM10、PM2.5)浓度推算值,使用AERMOD和CALPUFF模式计算燃煤电厂排放源导致的大气颗粒物浓度,对大气颗粒物浓度的计算值与实测值进行了比较分析与评估。结果表明:在城市区域,性能较佳的大气颗粒物浓度计算模式是AERMOD模式。     

气溶胶单颗粒分析方法的应用和进展

大气颗粒物污染由于其对区域环境和人体健康的影响而日益成为全球关注的焦点。相对于全颗粒物分析方法,大气单颗粒分析方法可以获得特征单颗粒的形貌、元素组成及粒子数量粒径谱等大量信息,具有采样量少、样品处理过程简单和分析速度快的特点,这使得单颗粒分析已成为表征大气颗粒物理化特征的重要手段。该方法已在源解析、颗粒物基本理化特性、颗粒物的混合状态和老化过程等方面得到应用。本文就单颗粒分析主要方法及其在颗粒物源解析等大气环境化学研究中的应用进行介绍,并对比分析不同单颗粒分析仪器的特点。     

开封大气扬尘颗粒物的来源解析

为了解析河南省开封市大气扬尘颗粒物的来源,对开封市的扬尘源成分谱和大气颗粒物PM_(10)进行采样,提取城市扬尘源中各单一源类的标识物,分析PM_(10)化学组分,应用化学质量平衡模型(CMB)和二重源解析技术进行定性和定量分析。结果表明:开封市PM_(10)污染严重,主要是城市扬尘,对环境空气中颗粒物的贡献在27. 7%,是首要污染因素;二次颗粒物对PM_(10)的贡献率达到26. 92%;汽车尾气尘对PM_(10)的贡献率在11. 29%。     

长春市2006—2007年采暖期大气降尘来源研究

研究长春市2006—2007年采暖期大气降尘的来源,采用电感耦合等离子体法分析降尘中的元素组成,应用富集因子法分析大气降尘中各元素的来源,应用化学质量平衡法分析各污染源的特征元素。结果表明:大气降尘样品中主要元素有As、Mn、Ca、Mg、Fe、Ti、Al、Pb、Zn和Cu;采暖期间长春市区的大气降尘首要来源是燃煤尘,其次是土壤风沙尘;降尘中各污染源特征元素是,建筑尘为Ca元素,土壤风沙尘为Al元素,机动车尾气尘为Pb、Zn元素,燃煤尘为Ti、Mn元素,道路尘为Fe元素;富集因子法和化学质量平衡法在元素的来源分析上具有很好的一致性。     

南京市东郊大气颗粒物污染特征

为了研究南京东郊大气颗粒物污染特征,利用安德森8级粒度分布采样器采样,并结合大气监测数据,综合分析2013—2014年间南京东郊大气颗粒物的粒度分布特征和大气污染物的污染水平及其相互关系。结果表明:南京市大气污染主要由粒径为0.43~2.10μm的大气颗粒物引起,其中12月份污染最严重,且首要污染物为细颗粒物PM2.5;温度、降雨量、风速等气象因素对颗粒物呈负相关性影响;灰霾天时颗粒物浓度受SO2、NO2的正相关性影响比非灰霾天时大,且NO2浓度对颗粒物浓度的影响比SO2浓度的影响大。     

中子活化分析测定大气颗粒物的质量保证

仪器中子活化分析具有灵敏度高、无需样品预处理、可测元素种类多等优点,是大气颗粒物元素含量分析的常用方法之一,为污染源解析提供重要的数据基础。本文归纳整理了NAA实验室利用相对比较法和单比较器k0法分析大气颗粒物样品工作中各实验流程的质量保证过程,以及内、外部质量控制方法。     

杭州市大气悬浮颗粒PM_(2.5)污染状况及化学组成特征分析

为了解杭州市大气悬浮颗粒物PM2.5污染状况及化学组成特征,2006年在杭州市内布设2个监测点位,按季节进行采样,并对悬浮颗粒物PM2.5中20种元素进行定量研究。结果表明:杭州市区大气中悬浮颗粒物PM2.5的年均质量浓度值为77.5μg/m3,其中S、Si、Ca、K等元素年平均质量浓度大于1.0μg/m3。元素Si、Al、Fe、Mg、V、K、Na、Ti、Mn、Ca、P、Cr、Ni主要来源于地壳,而元素Cl、Cu、Zn、Pb、As、Br、S、Se等主要来源于人为排放源。     

沈阳城区春节期间大气细颗粒元素浓度及其来源

为了解城市春节期间大量燃放烟花爆竹造成的大气污染状况,对沈阳城区进行了大气气溶胶分级采样,对细颗粒样品中41种元素进行了分析。结果表明:春节期间空气中污染物浓度明显高于平时状态,其中燃放烟花爆竹的标识元素Ba、Sr、K等元素浓度非常高;由交通和工业生产产生的污染元素Cd、As、B、Pb、Zn等在细颗粒中也有大量的富集,显示了春节期间除燃放烟花爆竹造成的颗粒物污染外,来自冶炼、餐饮、化学工业以及汽车尾气等人为污染源的释放也占有重要地位。     

A review of atmospheric fine particulate matter and its associated trace metal pollutants in Asian countries during the period 1995-2005

Many studies have monitored atmospheric particulates and gaseous phases of PM(2.5) in Asia over the past 10 years. This work also compared and discussed different sample collection, pretreatment and analytical methods in Asia countries in past decade. The results indicated that the main PM(2.5) sources are traffic exhausts. PM(2.5) concentrations are also ranked highest in the areas of traffic, followed by the urban sites, and lowest in rural sites in Asian countries. This work elucidates the sources, analytical tools, and the average concentrations for PM(2.5) and related metallic elements during 1995-2005. The results indicated that the average highest concentrations order of metallic elements for PM(2.5) were Fe>Mg>Zn, and the average concentrations of lowest metallic elements was Pb>Cu>Mn>Cr>Cd. The results also indicated that the concentration of metallic element Cu increased as the averaged concentrations of metallic element Zn and Mn increased during the past 10 years in Asian countries.     

中国沙尘暴及其监测预警

利用1954—2001年中国大陆681个站的气象资料，分析了中国沙尘暴的时空分布特征和分级标准，给出了沙尘暴若干观测事实。通过分析沙尘暴的发生发展机制，讨论了沙尘暴的定性预报和定量预报技术，指出发展包含大气运动、风蚀物理过程和下垫面地表信息的集合数值预报模式是沙尘暴定量预警技术的发展方向。同时，指出传统的监测网尚不能全面监测沙尘暴的发生和发展，建立包含下垫面生态环境要素、大气物理化学要素的专业化沙尘监测网络是深化对沙尘暴特性认识和发展沙尘暴定量预警技术的基础。     

沙尘期间大气颗粒PM_(10)与PM_(2.5)化学组分的浓度变化及来源研究

于2006年3月—4月北京沙尘发生期间,监测了沙尘与非沙尘期间悬浮颗粒PM10和PM2.5质量浓度,分析了样品中无机水溶性离子和金属元素。结果显示:沙尘天气导致PM10和PM2.5质量浓度上升,粗颗粒物质量浓度明显上升,细颗粒物受到的影响相对较小。SO42-、NO3-和NH4+为PM10与PM2.5主要水溶性离子。沙尘与非沙尘期间SO42-、NO3-和NH4+浓度变化表现出不稳定性,可能与沙尘的强度和持续时间、来源有关,沙尘下来自于土壤源Ca2+和Mg2+浓度都显然提高。沙尘期间Sc、Ti、V、Cr、Mn、Co、Ni、Rb和Cs金属元素浓度高于非沙尘期间浓度,并且富集因子系数都小于10,说明主要来自于自然源,而Zn、Se、Cd、Pb和Bi这5种元素浓度随沙尘的侵入并没增加其含量,反而使浓度有所下降,富集因子和富集程度对比表明这些元素主要来自于当地污染源。     

Dust optical properties retrieved from ground-based polarimetric measurements

We have systematically processed one year of sunphotometer measurements (recorded at five AERONET/PHOTONS sites in Africa) in order to assess mineral dust optical properties with the use of a new polarimetry-based algorithm. We consider the Cimel CE318 polarized sunphotometer version to obtain single-scattering albedo, scattering phase matrix elements F(11) and F(12) for dust aerosols selected with Angstr?m exponents ranging from -0.05 to 0.25. Retrieved F(11) and F(12) differ significantly from those of spherical particles. The degree of linear polarization -F(12)/F(11) for single scattering of atmospheric total column dust aerosols in the case of unpolarized incident light is systematically retrieved for the first time to our knowledge from sunphotometer measurements and shows consistency with previous laboratory characterizations of nonspherical particles.     

Bio-geochemically inspired capacitive sensors for heavy metals pollution monitoring

A novel sensor for environmental pollution monitoring is presented in this paper. A capacitive measuring system, together with suitable signal conditioning electronics, has been developed for performing real-time estimations of heavy metals concentration in air particulate. The proposed measuring system is biologically inspired from the observation of lichens that are widely used as bio-monitors for the environmental pollution. A synthetic replica of such bio-chemical elements has been developed regarding their behavior in the trapping of atmospheric particulate. A capacitive probe is then applied to this substrate in order to perform conversion of trace element concentration to an electric signal. The proposed prototype has been characterized through a large set of measurements performed in laboratory conditions with several pollutants as found in the real environment: features such as element selectivity and sensitivity to pollutant concentration have been highlighted. A procedure for performing both the pollutant classification and the estimation of its concentration has also been developed.     

Wind-induced dust generation and transport mechanics on a bare agricultural field

Strong atmospheric winds may cause wind erosion and dust emissions on bare, dry, erodible fields. Since these dust emissions may exceed particulate matter limits established by the United States Environmental Protection Agency, information on dust generation and transport mechanics is needed to determine the particulate hazard of dust sources. Measurements of climatic variables and airborne sediment mass and concentration were made during three strong wind events on a bare, fine sandy loam field in west Texas. This study clearly shows that dust flux estimates were very sensitive to dust concentration measurement height. PM10 flux values estimated between heights of 2 and 5m were 2-5 times those estimated between heights of 5 and 10 m. Tower placement in relation to the upwind unerodible boundary produced significant differences in dust flux that varied with storm intensity. During the most intense storm event, the PM10 flux between heights of 2 and 5m measured at the tower 200 m from the unerodible boundary was almost 2.5 times as that measured at the tower 100 m from the unerodible boundary. Vertical PM10 dust flux was closely related with horizontal sediment flux only when the winds came from the same direction during the entire duration of horizontal sediment flux measurements.     

Determination of low-Z elements in individual environmental particles using windowless EPMA

The determination of low-Z elements such as carbon, nitrogen, and oxygen in atmospheric aerosol particles is of interest in studying environmental pollution. Conventional electron probe microanalysis technique has a limitation for the determination of the low-Z elements, mainly because the Be window in an energy-dispersive X-ray (EDX) detector hinders the detection of characteristic X-rays from light elements. The feasibility of low-Z element determination in individual particles using a windowless EDX detector is investigated. To develop a method capable of identifying chemical species of individual particles, both the matrix and the geometric effects of particles have to be evaluated. X-rays of low-Z elements generated by an electron beam are so soft that important matrix effects, mostly due to X-ray absorption, exist even within particles in the micrometer size range. Also, the observed radiation, especially that of light elements, experiences different extents of absorption, depending on the shape and size of the particles. Monte Carlo calculation is applied to explain the variation of observed X-ray intensities according to the geometric and chemical compositional variation of individual particles, at different primary electron beam energies. A comparison is carried out between simulated and experimental data, collected for standard individual particles with chemical compositions as generally observed in marine and continental aerosols. Despite the many fundamental problematic analytical factors involved in the observation of X-rays from low-Z elements, the Monte Carlo calculation proves to be quite reliable to evaluate those matrix and geometric effects. Practical aspects of the Monte Carlo calculation for the determination of light elements in individual particles are also considered.     

基于风廓线雷达技术的沙尘天气监测研究

利用塔克拉玛干沙漠大气环境观测试验站2010年4月11日沙尘天气风廓线雷达资料,分析了此次过程启动爆发的水平风场、垂直速度和雷达等效回波强度特征。研究表明:风廓线雷达是进行沙尘探测和监测的一种有效的高空大气遥感系统,它不仅可以捕捉到沙尘天气的开始和结束时间,而且能监测到沙尘在空中被输送的高度、厚度范围以及沙尘运动的垂直强度特征;塔克拉玛干沙漠扬沙和沙尘暴雷达等效回波强度约为-3～10 dBZ,浮尘等效回波强度约为-15～-3 dBZ;水平风垂直切变以及低空东风的维持是此次沙尘天气发生的动力成因。扬沙、沙尘暴发生时,大气垂直速度表现为上升运动,在较大水平风速及干燥下垫面的配合下,导致地面沙粒被输送到高空,形成了沙尘天气。     

Characterization of PM10 fraction of road dust for polycyclic aromatic hydrocarbons (PAHs) from Anshan, China

Nineteen road dust samples were collected during 2005 in different parts of the urban area of Anshan, Liaoning Province, China, and 11 polycyclic aromatic hydrocarbons (PAHs) species were quantitatively analyzed using GC–MS. The results indicated that the total average concentration of PAHs over the investigated sites ranged from 48.73 to 638.26 μg/g, with a mean value of 144.25 μg/g, higher than the concentrations measured in previous studies. PAHs concentrations were higher with high molecular weight homologues (4–6 rings PAHs), accounting for 83.24–96.98%, showing combustion of petroleum fuels was a potential source. Organic carbon in road dust was considered one of the important factors that influenced the concentrations of PAHs in this study, and it was found that concentrations of total PAHs were correlated with those of organic carbon in road dust. The results of diagnostic ratios analysis showed traffic emission (gasoline or diesel) was one of the most important sources of road dust PAHs. Principal component analysis (PCA) indicated that the major sources of road dust PAHs might be emission from traffic, steel industry, cooking and coal combustion.