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1.
Nowadays, high-time resolved aerosol studies are mandatory to better understand atmospheric processes, such as formation, removal, transport, deposition or chemical reactions. This work focuses on PM10 physical and chemical characterisation with high-time resolution: elements (from Na to Pb), ions and OC/EC fractions concentration were determined during two weeks in summer and two in winter 2006 with 4-hours resolution. Further measurements aimed at hourly elemental characterisation of fine and coarse fractions and at the determination of particles number concentration in the 0.25-32 microm size range in 31 bins. The chemical mass closure was carried out in both seasons, enhancing intra-day differences in PM10 composition. In Milan, the highest contribution came from organic matter (34% and 33% in summer and winter, respectively); other important contributors were secondary inorganic compounds (16% and 24% in summer and winter, respectively) and, in summer, crustal matter (14%). Temporal trends showed strong variations in PM10 composition during contiguous time-slots and diurnal variations in different components contribution were identified. Moreover, peculiar phenomena, which would have hardly been detected with 24-hours samplings, were evidenced. Particles removal due to precipitations, aerosol local production and long range transport were studied in detail.  相似文献   

2.
采用单颗粒气溶胶飞行时间质谱仪(Single Particle Aerosol Mass Spectrometer,SPAMS)对西安市大气矿尘颗粒物进行连续12 d在线分析,共采集到107 425个同时含有正负质谱信息的矿尘颗粒,矿尘颗粒物占PM_(2.5)样本数的8.44%。结果表明,矿尘颗粒物的正离子碎片成分以Na~+、K~+、Al~+、Ca~+、CaO~+、Fe~+为主,同时还含有Pb~+等,负离子碎片成分以NO~-_2和NO~-_3为主,另外还含有HSO~-_4、SiO~-_3、HSiO~-_3、H(NO_3)~-_2等。在西安市大气细颗粒物中,矿尘颗粒物中贡献较大的几类(如含钙、含铁、铁氧颗粒物等)大多是老化的成分。将观测阶段采集到的矿尘颗粒纳入本地污染源谱进行来源分析,其主要来源为扬尘源、工业源、燃煤源和汽车尾气源等。  相似文献   

3.
大连市区大气气溶胶的无机化学特征分析   总被引:5,自引:0,他引:5  
通过对大连市的两个采样点从2002年4月至12月三个期间的气溶胶的三种粒径的采样分析,结果表明,大连市区气溶胶中PM10质量浓度约占TSP的50%,PM2.5质量浓度约占TSP的30%;8种可溶性离子在不同粒径气溶胶中所占的比例,随着粒径的减小而增大,冬季的SO42-、NO3-、NH4 在各种粒子中含量高于夏季,沙尘暴期间各种可溶性离子在不同粒径颗粒物中的含量较低;11种常见元素在细粒子中的含量比粗粒子中的含量高,春季各种粒子中的元素含量要高于冬季.  相似文献   

4.
乌鲁木齐市可吸入颗粒物水溶性离子特征及来源解析   总被引:2,自引:1,他引:1  
采暖期时在乌鲁木齐市采集了环境空气中的可吸入颗粒物,对可吸入颗粒物质量浓度及8种水溶性离子的特征和来源进行了分析。结果表明,细粒子和粗粒子的月平均质量浓度分别是53.5~233.3μg/m3和38.9~60.9μg/m3;细粒子和粗粒子中水溶性离子主要由SO24-、NH4+和NO3-组成;粗粒子中NH4+与NO3-和SO24-的相关性分别是0.70和0.66,细粒子中NH4+与NO3-和SO24-的相关性分别是0.89和0.93,铵盐是乌鲁木齐可吸入颗粒物主要存在形式;煤烟尘是乌鲁木齐市采暖期可吸入颗粒物的主要来源。  相似文献   

5.
石家庄市大气颗粒物中水溶性无机离子污染特征研究   总被引:3,自引:0,他引:3  
用超声萃取-离子色谱法分析了石家庄市大气颗粒物中8种水溶性无机离子。结果表明,NO3-、SO2-4、NH4+及 Ca2+为主要组分;各个离子的质量浓度均有季节及空间变化差异;不同粒径颗粒物中 SO2-4和 NO3-相关性均很好,NH4+与 SO2-4、NO3-在细颗粒物中具有良好的相关性,Ca2+在粗粒子中与 NO3-和 SO2-4的相关性也较好。SO2-4/NO3-质量比季节变化表明,春、夏季固定源与流动源对大气颗粒物贡献相当,秋季流动源贡献较大,冬季固定源贡献较大。PM2.5中SO2与SO2-4、NO2与 NO3-转化率表明,SO2-4、NO3-主要是由二次转化而来。  相似文献   

6.
Soil dust particles transported from loess regions of the Asian continent, called Asian dust, highly influences the air quality of north-eastern Asia and the northern Pacific Ocean. In order to investigate the effects of these dust storms on the chemical composition of atmospheric aerosol particles with different size, measurements of size distributions of total aerosol and major ion species were carried out on Jeju Island, Korea during April 2001. Juju Island was chosen for the study because the levels of emissions of anthropogenic air pollutants are very low. A 5-stage cascade impactor was used to sample size-fractionated aerosol particles. Samples were analyzed for major water-soluble ions using Dionex DX-120 ion chromatograph. The average mass concentration of total aerosol was found to be 24.4 and 108.3 microg m(-3) for non-Asian dust and Asian dust periods, respectively. The total aerosol size distribution, measured during the non-Asian dust period, was bimodal, whereas the coarse particles dominated the size distribution of total aerosol during the Asian dust period. It was found that SO4(2-), NH4+ and K+ were mainly distributed in fine particles, while Cl-, NO3-, Na+, Mg2+ and Ca2+ were in coarse particles. Although SO4(2-) was mainly distributed in fine particles, during the Asian dust period, the concentrations in coarse particles were significantly increased. This indicates heterogeneous oxidation of SO2 on wet surfaces of basic soil dust particles. The NH4+ was found to exist as (NH4)2SO4 in fine particles, with a molar ratio of NH4+ to SO4(2-) of 2.37 and 1.52 for non-Asian dust and Asian dust periods, respectively. Taking into account the proximity of the sampling site to the sea, and the observed chloride depletion, coarse mode nitrate, during the non-Asian dust period, is assumed to originate from the reaction of nitric acid with sodium chloride on the surfaces of sea-salt particles although the chloride depletion was not shown to be large enough to prove this assumption. During the Asian dust period, however, chloride depletion was much smaller, indicating coarse nitrate particles were mainly produced by the reaction of nitric acid with surfaces of basic soil particles. Most chloride and sodium components were shown to originate from sea-salt particles. Asian dust aerosols, arriving at Jeju Island, contained considerable amounts of sea-salt particles as they passed over the Yellow Sea. Ca2+ was shown to be the most abundant species in Asian dust particles.  相似文献   

7.
为探究典型燃煤工业城市邯郸市的大气细颗粒物(PM2.5)污染水平及水溶性无机离子特征,于2016年1—12月采集了当地大气PM2.5样品,然后利用离子色谱法测得水溶性无机离子的组分,分析了不同季节水溶性无机离子随PM2.5的浓度变化特征。通过对PM2.5中的阴离子、阳离子进行分析发现,SO4^2-、NO3^-和NH4^+在春夏秋冬四季均为PM2.5中的主要离子成分,SO4^2-、NO3^-和NH4^+的浓度之和在春夏秋冬四季占各季节总的水溶性无机离子浓度的百分比分别为84.6%、77.4%、89.9%、62.5%。其中,在春季和冬季含量最高的3种离子分别是NO3^-、SO4^2-和NH4^+,夏季含量最高的3种离子分别是SO4^2-、NH4^+和NO3^-,而秋季含量最高的3种离子分别是NH4^+、SO4^2-和NO3^-。相关性分析发现,2016年春季、夏季和秋季PM2.5为酸性,冬季为碱性。SO4^2-、NO3^-、NH4^+浓度分析表明,冬季PM2.5中的一次建筑扬尘排放较多。通过主成分分析法得出,PM2.5中水溶性无机离子主要来源于二次转化和生物质燃烧。  相似文献   

8.
In this study, PM10 concentrations and elemental (Al, Fe, Sc, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sn, Sb, Ba, Pb, and Bi) contents of particles were determined in Düzce, Turkey. The particulate matter samplings were carried out in the winter and summer seasons simultaneously in both urban and sub-urban sampling sites. The average PM10 concentration measured in the winter season was 86.4 and 27.3 μg/m3, respectively, in the urban and sub-urban sampling sites, while it was measured as 53.2 and 34.7 μg/m3 in the summer season. According to the results, it was observed that the PM10 levels and the element concentrations reached higher levels, especially at the urban sampling site, in the winter season. The positive matrix factorization model (PMF) was applied to the data set for source apportionment. Analysis with the PMF model revealed six factors for both the urban (coal combustion, traffic, oil combustion, industry, biomass combustion, and soil) and sub-urban (industry, oil combustion, traffic, road dust, soil resuspension, domestic heating) sampling sites. Loadings of grouped elements on these factors showed that the major sources of the elements in the atmosphere of Düzce were traffic, fossil fuel combustion, and metal industry-related emissions.  相似文献   

9.
Measurements of aerosols were made in 2001 and 2002 at Dunhuang (40 degrees 00'N, 94 degrees 30'E), China to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had noticeable peaks in super micron size range not only in the boundary mixing layer but also in the free troposphere. Super-micron particle concentration largely decreased in the mid tropopause (from 5 to 10 km; above sea level, a.s.l.). Lidar measurements made during August 2002 at Dunhuang suggested the possibility that mixing of dust particles occurred from near the ground to about 6 km even under calm weather conditions, and a large depolarization ratio of particulate matter was found in the aerosol layer. The top of the aerosol layer was found at heights of nearly 6 km (a.s.l.). It is strongly suggested that nonspherical dust particles (Kosa particles) frequently diffused in the free atmosphere over the Taklamakan desert through small-scale turbulences and are possible sources of dust particles of weak Kosa events that have been identified in the free troposphere not only in spring but also in summer over Japanese archipelago. Electron microscopic experiments of the particles collected in the free troposphere confirmed that coarse and nonspherical particles observed by the mineral particle were major components of coarse mode (diameter larger than 1 microm) below about 5 km over Dunhuang, China.  相似文献   

10.
近年来,空气污染已成为长三角地区最关键的环境问题之一,气溶胶颗粒物(PM)是最主要的污染物之一.生物气溶胶作为颗粒物的重要组成部分,可能对空气质量和人体健康产生不利影响.利用高通量测序方法研究了江苏省泰州2019年11月至2020年1月期间发生沙尘和霾污染时生物气溶胶中细菌群落结构组成特征.结果表明:冬季沙尘天和霾天气...  相似文献   

11.
A field study aimed to characterize atmospheric pollutants in the gaseous and the particulate phases was conducted during the fall-winter of 2004 and the summer of 2005 in the Ashdod area, Israel. The site is influenced by both anthropogenic sources (power plants, refineries, chemical and metal industries, a cargo port, road traffic) and natural sources (sea-spray and desert dust). The use of diffusion lines--a series of annular diffusion denuders for sampling gaseous compounds followed by a cyclone and a filter pack for determining PM(2.5) composition--allowed a good daily characterization of the main inorganic compounds in both the gaseous (HCl, HNO(3), SO(2), NH(3)) and the particulate phase (Cl(-), NO(3)(-), SO(4)(=), NH(4)(+), and base cations). During the summer campaign two other activities were added: an intensive 3-h sampling period and the determination of PM(2.5) bulk composition. The results were interpreted on the basis of meteorological condition, especially the mixing properties of the lower atmosphere as determined by monitoring the natural radioactivity due to Radon progeny, a good proxy of the atmospheric ability to dilute pollutants. Several pollution episodes were identified and the predominance of different sources was highlighted (sea-spray, desert dust, secondary photochemical pollutants). During the summer period a considerable increase of nitric acid and particulate sulphate was observed. Secondary inorganic pollutants (nitrate, sulphate and ammonium) constituted, on the average, 57% of the fine particle fraction, organic compounds 20%, primary anthropogenic compounds 14%, natural components (sea-spray and crustal elements) 9%. The advantages of the diffusion lines in determining gaseous and particulate N- and S- inorganic compounds are discussed.  相似文献   

12.
PM2.5是城市大气的主要污染物,对人体健康危害巨大。研究PM2.5的形貌特征及矿物组成有助于解析PM2.5的来源和贡献及评估PM2.5对人体健康的风险。利用高分辨率场发射扫描电镜(FESEM)和能谱(SEM-EDX)对以石化为支柱产业的奎屯-独山子石化区域生活区和工业区的夏季、秋季PM2.5的形貌和矿物类型进行了分析。结果表明,奎屯-独山子的PM2.5主要包括矿物颗粒(规则矿物、不规则矿物)、烟尘集合体、球形颗粒(燃煤飞灰和二次粒子)、其他颗粒(生物质、未知颗粒)等4种类型,其中矿物颗粒在数量上和体积上均占优势。夏季规则矿物颗粒较多。从元素组成分析看,夏季PM2.5有"富Si"、"富Al"、"富Fe"、"富Ca"、"富Cu"、"富Zn"等类型,秋季PM2.5有"富Si"、"富Ca"、"富Fe"、"富Zn"、"富Cu"、"富Ti"、"富Ba"等类型,2个季节均以"富Si"颗粒占优势,表明道路扬尘、燃油飞灰、燃煤飞灰、工业粉尘、机动车尾气尘、城市扬尘等污染源是奎屯-独山子石化区夏季和秋季大气污染的主要来源。  相似文献   

13.
To analyze polycyclic aromatic hydrocarbons (PAHs) at an urban site in Seoul, South Korea, 24-hr ambient air PM2.5 samples were collected during five intensive sampling periods between November 1998 and December 1999. To determine the PAH size distribution, 3-day size-segregated aerosol samples were also collected in December 1999. Concentrations of the 16 PAHs in the PM2.5 particles ranged from 3.9 to 119.9 ng m−3 with a mean of 24.3 ng m−3.An exceptionally high concentration of PAHs(∼120 ng m−3) observed during a haze event in December 1999 was likely influenced more by diesel vehicle exhaust than by gasoline exhaust, as well as air stagnation, as evidenced by the low carbon monoxide/elemental carbon (CO/EC) ratio of 205 found in this study and results reported by previous studies. The total PAHs associated with the size-segregated particles showed unimodal distributions. Compared to the unimodal size distributions of PAHs with modal peaks at < 0.12 μm measured in highway tunnels in Los Angeles (Venkataraman and Friedlander, 1994), four- to six-ring PAHs in our study had unimodal size distributions, peaking at the larger size range of 0.28–0.53 μm, suggesting the coagulation of freshly emitted ultrafine particles during transport to the sampling site. Further, the fraction of PAHs associated with coarse particles(> 1.8 μm) increased as the molecular weight of the PAHs decreased due to volatilization of fine particles followed by condensation onto coarse particles.  相似文献   

14.
The contribution of fugitive dust from traffic to air pollution can no longer be ignored in China. In order to obtain the road dust loadings and to understand the chemical characteristics of PM10 and PM2.5 from typical road dust, different paved roads in eight districts of Beijing were selected for dust collection during the four seasons of 2005. Ninety-eight samples from 28 roads were obtained. The samples were resuspended using equipment assembled to simulate the rising process of road dust caused by the wind or wheels in order to obtain the PM10 and PM2.5 filter samples. The average road dust loading was 3.82 g m − 2, with the highest of 24.22 g m − 2 being in Hutongs in the rural–urban continuum during winter. The road dust loadings on higher-grade roads were lower than those on lower-grade roads. Attention should be paid to the pollution in the rural–urban continuum areas. The sums of element abundances measured were 16.17% and 18.50% for PM10 and PM2.5 in road dust. The average abundances of OC and EC in PM10 and PM2.5 in road dust were 11.52%, 2.01% and 12.50%, 2.06%, respectively. The abundance of elements, water-soluble ions, and OC, EC in PM10 and PM2.5 resuspended from road dust did not change greatly with seasons and road types. The soil dust, construction dust, dust emitted from burning coal, vehicle exhaust, and deposition of particles in the air were the main sources of road dust in Beijing. Affected by the application of snow-melting agents in Beijing during winter, the amount of Cl −  and Na +  was much higher during that time than in the other seasons. This will have a certain influence on roads, bridges, vegetations, and groundwater.  相似文献   

15.
利用2019—2021年合肥市气象参数、颗粒物浓度、颗粒物化学组分、颗粒物散射系数、颗粒物粒径谱等的逐小时观测数据,分析了合肥市大气能见度变化趋势及其影响因素。结果表明,2019—2021年,合肥市能见度呈逐年上升的总体特征,并且在季节变化上呈现为夏高冬低,在日变化上呈现为午后最高、夜间最低。相关性分析结果显示,合肥市能见度与颗粒物浓度、相对湿度均呈显著负相关关系,且能见度与相对湿度的相关程度比与颗粒物浓度的相关程度高15.5%~219.2%。相对湿度是直接影响合肥市能见度的主要因素之一,而温度、风速对能见度的间接影响作用相对较小。能见度与颗粒物特性关系研究结果表明:能见度与水溶性离子的相关程度高于与碳质组分的相关程度;当能见度处于较低水平时,能见度与PM2.5主要组分浓度的相关性明显减弱,相对湿度、超细颗粒物占比、水溶性离子含量和碳质组分含量等因素对能见度的影响逐渐凸显;在较高PM2.5浓度环境条件下,颗粒物散射系数的显著变化是导致能见度降低的主要原因;小粒径颗粒物对合肥市大气能见度的影响程度相对较高,应优先大幅度降低PM1.0浓度。  相似文献   

16.
Aerosol size distributions, trace gas, and PM(2.5) concentrations have been measured in urban Jinan, China, over 6 months in 2007 and 2008, covering spring, summer, fall, and winter time periods. Number concentrations of particles (10-2,500 nm) were 16,200, 13,900, 11,200, and 21,600 cm(?-3) in spring, summer, fall, and winter, respectively. Compared with other urban studies, Jinan has higher number concentrations of accumulation-mode particles (100-500 nm) and particles (10-2,500 nm), but lower concentrations of ultrafine particles (10-100 nm). The number, surface and volume concentrations, and size distributions of particles showed obvious seasonal variation and are also influenced by traffic emissions. Through correlation analysis, traffic emissions are proposed to be a more important contributor to Atkien-mode and accumulation-mode particles than coal firing. Around midday, the presence of nanoparticles and new particle formation is limited to pre-existing particles from traffic emissions and the mass transport of particles from suburban and rural areas. Compared with other studies in urban areas of Europe and the USA, the variation of particle number concentration and related gas concentration in Jinan between weekdays and weekends is smaller and the reasons has been deduced.  相似文献   

17.
Water-soluble inorganic ions in aerosol samples have been studied. The sample collection took place during summer in 2003 at a European background site which is operating within the framework of the European Monitoring and Evaluation Program. Gent type PM10 stacked filter unit (SFU) samplers were operated in parallel on a day and night basis to collect particles in separate coarse (2.0-10 microm) and fine (<2.0 microm) size fractions. Particulate masses were measured gravimetrically; the filters from one of the SFU samplers were analyzed by particle-induced X-ray emission spectrometry (PIXE) and instrumental neutron activation analysis (INAA). Filters from the other SFU sampler were analyzed by ion chromatography (IC) for major inorganic anions (MSA-, NO2(-), NO3(-), Cl-, Br-, SO4(2-), oxalate) and cations (Na+, K+, NH4(+), Mg2+, Ca2+). The water-soluble inorganic ions measured were responsible for 44% and 16% of the total fine and coarse particulate mass, respectively. In the fine size fraction, the main ionic components were SO4(2-) and NH4(+) accounting for about 90% of fine ionic mass. In the coarse fraction the main ionic components were Ca2+ and NO3(-), followed by SO4(2-). Significant day and night difference in the mass concentrations was observed only for fine NO3(-). The molar ratios of fine NH4(+) to SO4(2-) indicated their complete neutralization to (NH4)2SO4. According to the cation-to-anion ratios the coarse particles were alkaline, while the fine particles were slightly acidic or neutral. By comparing the corresponding concentrations obtained from PIXE/INAA and IC, we determined the water-extractable part of the individual species. We also investigated the effect of long-range transported air masses on the local air concentrations, and we found that the air quality of this background monitoring station was affected by regional pollution sources.  相似文献   

18.
Complementary studies on the inorganic chemical composition of Nerium oleander leaves collected in the town of Messina (Sicily, Italy) and seven grain-size fractions of local roadway dust have been carried out. Data and maps are presented to show that the particulate matter present in the air of Messina contains trace elements significantly in excess with respect to the average continental earth crust. The anomalies follow the outline of the urban area, the highest concentrations of trace elements being observed where traffic density is highest. Chemical and isotopic analyses of both road dust and Nerium oleander leaves indicate that Pb contamination still characterizes roads with heavy traffic. In addition to Pb, other metals such as Pt, Pd, Sb, Au, Br, Zn, Cu, Mo, and Cd are significantly enriched in roadway dust, indicating their common anthropogenic origin, especially from traffic. SEM/EDS study of some roadway dust particles has shown the presence of gypsum probably of secondary origin, mixed particles formed by coagulation or gas-to-particle conversion, and porous spherical particles apparently emanating from combustion processes.  相似文献   

19.
The Po valley in northern Italy is renowned for its high air pollutant concentrations. Measurements of air pollutants from a background site in Modena, a town of 200 thousand inhabitants within the Po valley, are analysed. These comprise hourly data for CO, NO, NO(2), NO(x), and O(3), and daily gravimetric equivalent data for PM(10) from 1998-2010. The data are analysed in terms of long-term trends, annual, weekly and diurnal cycles, and auto-correlation and cross-correlation functions. CO, NO and NO(2) exhibit a strongly traffic-related pattern, with daily peaks at morning and evening rush hour and lower concentrations over the weekend. Ozone shows an annual cycle with a peak in July due to local production; notwithstanding the diurnal cycle dominated by titration by nitrogen oxide, the decreasing long term trend in NO concentration did not affect the long term trend in O(3), whose mean concentration remained steady over the sampling period. PM(10) shows a strong seasonality with higher concentration in winter and lower concentration in summer and spring. Both PM(10) and ozone show a marked weekly cycle in summer and winter respectively. Regressions of PM(10) upon NO(x) show a consistently greater intercept in winter, representing higher secondary PM(10) in the cooler months of the year. There is a seasonal pattern in primary PM(10) to NO(x) ratios, with lower values in winter and higher values in summer, but the reasons are unclear.  相似文献   

20.
The aim of this work is to characterize the mineral phases present in the atmosphere at three locations in northern Oman. Samples of atmospheric particles were collected using a high volume sampler. Three indoor and one outdoor location were chosen in this investigation. Sampling locations included a residential house located nearby the cement plant, a residential house located nearby a refinery plant, and a residential house located at Al-Suwayq residential area. Indoor air was sampled from these three houses. Moreover, for the Al-Suwayq residential house, sampling was also taken outside the house for comparison. The dust samples were analysed for their microanalysis characterization and their mineral contents as well. The microanalysis enabled us to identify the metals present in the particles. Furthermore, the mineralogical analysis of the sample filters showed the presence of quartz as the principal phase inside the house of Al-Suwayq, whereas quartz, dolomite, and gypsum were common phases outside the house. In the residential house nearby the cement plant, it was found that calcite, quartz, dolomite and goethite were the principal phases whereas the particles collected from the house nearby the refinery composed primarily of dolomite and calcite. The airborne dust collected at the refinery and Al-Suwayq were probably sourced in the natural environment and mobilised by natural processes. However, at the cement factory the crushing and grinding of limestone during the industrial process has contributed significantly to the airborne dust load. Generally, the information obtained in this study will be invaluable as no data for the mineral content of atmospheric dust existed in the Oman.  相似文献   

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