大气颗粒物及其组成研究进展(下)

颗粒物是空气中最重要的污染物之一,由于颗粒物表面的吸附作用,其组分非常复杂,其中含有多种有毒有害的化学成分,对大气环境造成不良影响,并危及人体健康。借助大气颗粒物及其组成成分的测定,通过污染源解析分析其来源及影响因素,控制大气颗粒物的排放,对于保证大气环境质量、改善人们的生存环境具有重大意义。本文对此进行综述,着重介绍大气颗粒物及其组成成分、源解析及测量技术的最新进展。     

柴油机车载诊断系统新型颗粒物传感器的研究

随着柴油机颗粒物排放法规的不断严格,颗粒物捕集器被广泛使用以去除尾气中的颗粒物。为了精确地监测尾气中的颗粒物排放,就需要采用新型的颗粒物传感器。该传感器需要有足够的耐热性和承受力,并且能够忍受恶劣的排气环境。文中介绍了几种国内外新型颗粒物传感器的工作原理及其研究方法,其中通过流场模拟对电阻传感器进行了研究,分析了电容传感器电场强制收集方法的碳烟收集效率,对电化学传感器电极加入离聚物后的变化进行了对比分析,并引入了有应用前景的颗粒物传感器。     

大气颗粒物中水溶性离子环境影响、来源及其监测技术

大气颗粒物中水溶性离子影响空气环境质量,影响人体健康,产生气候效应。本文对大气颗粒物中水溶性离子组成、来源及不同条件下对环境影响进行综述。同时,总结大气颗粒物中水溶性离子离线与在线监测方法及其在大气环境监测工作中应用。     

厦门市大气颗粒物中水溶性离子分布特征及其对酸雨的影响研究

为研究厦门市大气颗粒物的污染特征及其对酸雨的影响,于2012年12月至2013年7月在厦门市各区分别采集大气中TSP、PM10、PM2.5颗粒物样品,利用离子色谱法分析了其中的水溶性离子成分含量。结果表明,厦门市大气颗粒物中水溶性离子成分分布特征为：Na＋和Ca2＋离子主要主要分布在TSP、PM10中,而SO42-离子则主要分布在PM10和PM2.5中。说明Na＋和Ca2＋离子更容易富集在粗颗粒物粒子上,而SO42-离子主要存在于细颗粒物粒子中。厦门市大气颗粒物中对雨水酸度有重要缓冲作用的Ca2＋、Mg2＋离子浓度处于较低水平,说明厦门市大气颗粒物对雨水酸度缓冲作用较低,这是厦门地区酸雨发生率较高的原因之一。     

便携式PM2.5/PM10检测技术研究

大气PM2.5/PM10的检测在当今越发重要,其技术核心是检测误差和平行性。为了减小大气颗粒物的检测误差和仪器平行性,该文从PM10和PM2.5分离技术、恒流抽尘技术和细颗粒物浓度检测技术三个方面进行研究,研制了一种适用于大气环境的PM2.5/PM10检测的便携式仪器。实验证明:PM2.5/PM10旋风分离器满足设计要求,颗粒物检测仪误差小于2.2%,平行性误差小于4.8%,符合国家检测标准的要求。     

真空紫外光电离质谱及其在大气化学中的应用研究

大气环境污染成因复杂，往往涉及一系列复杂的化学反应过程，且包含众多的挥发性有机物气体分子、自由基和气溶胶颗粒物等，在线检测是大气化学领域的难点和热点问题。真空紫外光电离质谱技术使分子吸收单个光子能量后，在其电离能阈值附近“软”电离，可以获得分子离子质量信息，具有质谱图简洁、碎片离子少和易于解析等特点，能够从分子层面上在线测量大气化学反应过程中关键的化学成分，揭示复杂的大气化学反应机理，在大气化学领域具有较好的应用前景。本文介绍了基于真空紫外激光、同步辐射光源、自由电子激光和真空紫外放电灯等多种光源的真空紫外光电离质谱技术，阐述了近年来该技术在大气挥发性有机物、自由基以及气溶胶颗粒物化学成分检测方面的进展，并展望真空紫外光电离质谱技术的发展方向。     

大气颗粒物中左旋葡聚糖及其异构体的定量分析

大气颗粒物中的左旋葡聚糖是生物质燃烧的示踪物质,它极性强,可溶于水,与其它两个立体异构体同时排放,其定量分析对分析化学挑战很大。本文介绍了几种分析大气颗粒物中左旋葡聚糖及其异构体的方法,如气相色谱法、液相色谱法等,从仪器配置、样品前处理、分析条件等几个方面进行讨论,并对几种常用的方法进行了比较,对大气分析工作者进行方法选取及定量分析提供参考。     

大气颗粒物浓度在线监测方法研究

大气颗粒物浓度是大气污染监测中的一项重要指标.大气中的颗粒物,特别是PM10及其以下颗粒物浓度的监测一直是国内外专家关注的问题.本文提出一种采用振动原理在线测量颗粒物质量浓度的监测方法,替代了传统的离线监测技术,提高了监测工作的实时性和正确性.     

辽宁省典型城市大气中颗粒物污染状况及分布特征研究

研究了辽宁省典型城市大气中不同粒径颗粒物污染状况及分布特征,结果表明大气中TSP、PM10、PM2.5三种不同粒径颗粒物污染较重,颗粒物中PM10及以下细小颗粒所占比例较高.     

国内大气悬浮颗粒物检测分析方法

介绍了国内大气悬浮颗粒物的检测分析方法,包括源解析方法及预处理技术,重点介绍仪器分析方法,并比较了它们的优缺点,同时对目前研究进展进行了综述.     

我国大气污染的健康效应、主要成分及其检测方法

大气污染是目前我国面临的主要环境问题之一,已引起各界的广泛关注。我国城市大气呈现多污染源叠加的复合型污染特征,其导致的健康效应也更为复杂和严重,而我国关于大气污染细粒子来源、形成机制及其健康影响的研究尚无法满足控制和预防的需求。本文评述了大气污染的健康影响,并简要描述了我国大气污染主要污染物构成,最后对当前大气污染研究常用的检测方法进行了总结。     

Characterization of ultrafine coal fly ash particles by energy-filtered TEM

In this study, energy-filtered transmission electron microscopy is demonstrated to be a valuable tool for characterizing ultrafine coal fly ash particles, especially those particles encapsulated in or associated with carbon. By examining a series of elemental maps (K-edge maps of C and O, and L-edge maps of Si, Al, Ti and Fe) recorded using the three-window method, considerable numbers of titanium and iron species with sizes from several nanometres to submicrometre were shown to be present, typically as oxides dispersed in the carbonaceous matrix. Crystalline phases, such as rutile and iron-rich oxide spinel, were also identified from electron diffraction patterns and high-resolution TEM images. Information about these ultrafine coal fly ash particles regarding their size, morphology, elemental composition and distribution, and crystalline phases, which has not been available previously in conventional ash studies, should be useful in toxicological studies and related environmental fields.     

辽宁省五城市大气可吸入颗粒物中多环芳烃污染特征研究

为全面了解辽宁省大气可吸入颗粒物污染状况,2004年在省内选取了5个城市进行分季节采样,并对颗粒物中美国优先控制的16种多环芳烃（PAHs）进行了定量研究。结果表明,大气PM10和PM2.5中PAHs污染较重,且冬季高于其它季节,PAHs主要富集在PM2.5及以下细小颗粒物中。     

锦州市大气可吸入颗粒物中多环芳烃污染特征研究

为全面了解城市大气可吸入颗粒物污染状况,我们在2004年1、4、7、10四个月份采样四次,分别代表冬、春、夏、秋四个季节,对锦州市进行分季节采样,并对城市空气中可吸入颗粒物（PM10和PM2.5）中关国优先控制的16种多环芳烃（PAHs）进行了定量研究。结果表明,大气PM10和PM2.5中PAHs污染较重,且冬季高于其它季节,PAHs主要富集在PM2.5及以下细小颗粒物中。     

SPAMS打击率影响因素与仪器状态分析

在北京市环境保护监测中心空气质量综合观测实验室,使用气溶胶单颗粒飞行时间质谱（SPAMS）对2013年1~12月空气颗粒物开展综合观测。实验结果表明,SPAMS打击率与测径颗粒数（siz）、大气相对湿度、颗粒物组分以及粒径有关。仪器状态正常时,打击率在siz数量小、大气相对湿度低时较高,与含K⁺、HSO₄^-、OCEC、NO₃^-的颗粒物以及粒径为0.2~0.3 μm、0.3~0.4 μm、0.4~0.5 μm的颗粒物数量呈正相关,与0.1~0.2 μm、0.5~0.6 μm、0.6~0.7 μm的颗粒物数量呈负相关,含NH₄⁺、SiO₃^-颗粒物数量的关系与污染特征及其他环境有关。本研究通过分析打击率数值及打击率与各影响因素的关系判断仪器状态是否正常,这为提前发现常规方法难以发现的仪器故障提供了一种思路。     

HC-PM COUPLING MODEL FOR PARTICULATE MATTER EMISSION OF DIESEL ENGINES

A rapid, phenomenological model that predicts particulate matter (PM) emission of diesel engines is developed and formulated. The model is a chemical equilibrium composition model, and is based on the formation mechanisms of PM and unburned hydrocarbon (HC) emissions of diesel engines. It can evaluate the emission concentration of PM via the emission concentration of HC. To validate the model, experiments are carried out in two research diesel engines. Comparisons of the model results with the experimental data show good agreement. The model can be used to evaluate the concentration of PM emission of diesel engines under lack of PM measuring instruments. In addition, the model is useful for computer simulations of diesel engines, as well as electronic control unit (ECU) designs for electronically controlled diesel engines.     

MRT letter: Auto‐fluorescence by human alveolar macrophages after in vitro exposure to air pollution particles

Macrophages from smokers demonstrate an increased auto‐fluorescence. Similarly, auto‐fluorescence follows in vitro exposure of macrophages to cigarette smoke condensate (i.e., the particulate fraction of cigarette smoke). The composition of particles in cigarette smoke can be comparable to air pollution particles. We tested the postulate that macrophages exposed to air pollution particles could demonstrate auto‐fluorescence. Healthy nonsmoking and healthy smoking volunteers (both 18–40 years of age) underwent fiberoptic bronchoscopy with bronchoalveolar lavage and alveolar macrophages isolated. Macrophages were incubated at 37°C in 5% CO₂ with either PBS or 100 μg/mL particle for both 1 and 24 h. Particles included a residual oil fly ash, Mt. St. Helens volcanic ash, and ambient air particles collected from St. Louis, Missouri and Salt Lake City, Utah. At the end of incubation, 50 μL of the cell suspension was cytocentrifuged and examined at modes for viewing fluorescein isothiocyanate (FITC) and rhodamine fluorescence. Both emission source air pollution particles demonstrated FITC and rhodamine auto‐fluorescence at 1 and 24 h, but the signal following incubation of the macrophages with oil fly ash appeared greater. Similarly, the ambient particles were associated with auto‐fluorescence by the alveolar macrophages and this appeared to be dose‐dependent. We conclude that exposure of macrophages to air pollution particles can be associated with auto‐fluorescence in the FITC and rhodamine modes. Microsc. Res. Tech., 2010. © 2009 Wiley‐Liss, Inc.     

PM2.5-铵的单颗粒表征

在北京空气重污染期间,以石英膜采集的PM2.5为样本,采用飞行时间二次离子质谱(TOF-SIMS)结合质量高分辨模式与正负离子成像模式表征了PM2.5-铵。实验观察到了硫酸氢铵(NH₄HSO₄)单颗粒物,未见硝酸铵或氯化铵。实验验证了正、负离子成像之间微米级偏差的人工校正方法,同时阐明了TOF-SIMS表征PM2.5水溶性无机盐等成分的特点、优势和应用潜力。     

Mass spectrometry of atmospheric aerosols--recent developments and applications. Part II: On-line mass spectrometry techniques

Many of the significant advances in our understanding of atmospheric particles can be attributed to the application of mass spectrometry. Mass spectrometry provides high sensitivity with fast response time to probe chemically complex particles. This review focuses on recent developments and applications in the field of mass spectrometry of atmospheric aerosols. In Part II of this two-part review, we concentrate on real-time mass spectrometry techniques, which provide high time resolution for insight into brief events and diurnal changes while eliminating the potential artifacts acquired during long-term filter sampling. In particular, real-time mass spectrometry has been shown recently to provide the ability to probe the chemical composition of ambient individual particles <30 nm in diameter to further our understanding of how particles are formed through nucleation in the atmosphere. Further, transportable real-time mass spectrometry techniques are now used frequently on ground-, ship-, and aircraft-based studies around the globe to further our understanding of the spatial distribution of atmospheric aerosols. In addition, coupling aerosol mass spectrometry techniques with other measurements in series has allowed the in situ determination of chemically resolved particle effective density, refractive index, volatility, and cloud activation properties.