北京市地面街尘与径流中重金属的污染特征（Characteristics of Heavy Metals in Street Dusts and Urban Runoff in Beijing）

街尘作为城市各种污染物的载体和地表径流污染物的主要来源对水环境的影响日益受到关注.论文分析了北京市城区街尘与地表径流中重金属浓度和颗粒的粒径分布.结果表明:不同城市土地利用类型对街尘和径流中的重金属含量、颗粒粒径分布具有重要影响.在商业区、主要道路、住宅区、城中村4种土地利用类型中,街尘重金属浓度和地面单位面积重金属质量均以主要道路最高;径流重金属浓度由高到低顺序依次为:主要道路>城中村>居民区;主要道路和商业区街尘颗粒中细粒径占的比例较高,在全部土地利用类型的径流水样中颗粒物粒径分布差别不大;随着街尘中颗粒物粒径的减小,重金属浓度增加;街尘中小于149μm的颗粒物质量百分比和重金属浓度均较高,且在径流中这个粒径段的颗粒物含量也高,体积比达80%以上.建议在今后的城市街尘面源污染控制中应特别关注土地利用类型和街尘粒径的影响.     

Water-soluble inorganic ions in airborne particulates from the nano to coarse mode: a case study of aerosol episodes in southern region of Taiwan

In 2004, airborne particulate matter (PM) was collected for several aerosol episodes occurring in the southern region of Taiwan. The particulate samples were taken using both a MOUDI (Micro-orifice Uniform Deposit Impactor) and a nano-MOUDI sampler. These particulate samples were analyzed for major water-soluble ionic species with an emphasis to characterize the mass concentrations and distributions of these ions in the ambient ultrafine (PM_0.1, diameter <0.1 μm) and nano mode (PM_nano, diameter <0.056 μm) particles. Particles collected at the sampling site (the Da-Liao station) on the whole exhibited a typical tri-modal size distribution on mass concentration. The mass concentration ratios of PM_nano/PM_2.5, PM_0.1/PM_2.5, and PM₁/PM_2.5 on average were 1.8, 2.9, and 71.0%, respectively. The peak mass concentration appeared in the submicron particle mode (0.1 μm < diameter <1.0 μm). Mass fractions (percentages) of the three major water-soluble ions (nitrate, sulfate, and ammonium) as a group in PM_nano, PM_0.1, PM₁, and PM_2.5 were 18.4, 21.7, 50.0, and 50.7%, respectively. Overall, results from this study supported the notion that secondary aerosols played a significant role in the formation of ambient submicron particulates (PM_0.1−1). Particles smaller than 0.1 μm were essentially basic, whereas those greater than 2.5 μm were neutral or slightly acidic. The neutralization ratio (NR) was close to unity for airborne particles with diameters ranging from 0.18 to 1 μm. The NRs of these airborne particles were found strongly correlated with their sizes, at least for samples taken during the aerosol episodes under study. Insofar as this study is exploratory in nature, as only a small number of particulate samples were used, there appears to be a need for further research into the chemical composition, source contribution, and formation of the nano and ultrafine mode airborne particulates.     

洛阳市不同功能区地表灰尘重金属的粒径分布特征

以洛阳市为例,分析了工业区、商业区、居民区、城乡结合处、城市绿地和城市主干道等不同功能区地表灰尘颗粒组成及重金属（Cu、Zn、Pb、Cd）粒级效应。结果表明：洛阳市不同功能区地表灰尘粒径分布具多峰性,分别在850~250、150~96及〈75μm出现分布峰值。不同功能区地表灰尘粒径差异显著,居民区和城市绿地细颗粒比重较大,工业区和城市主干道粗颗粒相对较多。各金属元素的质量分数粒级效应不一,Pb在工业区各粒级中质量分数最高,具粒级效应,其它功能区粒级效应不明显,Cd、Cu粒级效应明显,Cd富集更趋向于细粒（96~75和〈75μm）,Cu在180~150μm粒径质量分数迅速升高,并随着粒径减小,基本呈上升趋势,除工业区和城乡结合部外,其它功能区均在〈75μm粒径达到峰值。除居民区和城乡结合部各粒径Zn分布较平均外,Zn主要富集于180~150μm粒径颗粒,且质量分数明显高于其它各粒级,粒级效应基本呈现正态分布。     

Air pollution from aluminum smelting plants. II. the contribution from an aluminum smelting plant using the söderberg process to polycyclic aromatic hydrocarbons and mutagens in ambient air

Extracts of airborne particles collected in the surroundings of an aluminum smelting plant have been analyzed for polycyclic aromatic hydrocarbons (PAH) and tested for mutagenic activity. The results were discussed in relation to the meteorological conditions during sampling and showed that the ambient concentrations of these parameters are significantly influenced by the emissions from the smelting plant in the summer, but not in the winter. The results from the mutagenicity testing showed that the mutagenic activity of particle extracts from this area was equal to or lower than what has been reported from other urban areas in Scandinavia.

The contribution of PAH and mutagens to the concentrations of these compounds in ambient air was estimated based on parallel measurements of fluoride and from emission values of fluoride, PAH and mutagens. It was concluded that whereas the smelter emissions could account for more than 50% of the yearly average of ambient PAH, the contribution of mutagens was significantly less.     

Pollution characteristics of particulate matters emitted from outdoor barbecue cooking in urban Jinan in eastern China

To understand the pollution characteristics of particulate matter emitted from outdoor barbecue cooking in eastern China, measurements of the PM_2.5 mass concentration, the number concentration of particles with a diameter of 0.01 to 1.0 μm, and the particle size distribution from 0.3 to 25 μm were carried out at seven barbecue restaurants in urban Jinan. The average PM_2.5 mass concentration and sub-micron particle number concentrations at a distance of 1 m from the grills were 250 to 1083 μg/m³ and 0.90 × 10⁵ to 2.23 × 10⁵ cm^–3, respectively, which were much higher than those in the ambient air of the urban area. Compared to the ambient atmosphere, barbecue cooking emitted very high levels of particles with a larger increase in the concentrations of super-micron particles than that of sub-micron particles. The super-micron particle number concentrations at the barbecue restaurants were 10 to 100 times higher than those observed in the ambient urban atmosphere. The barbecue smoke had a significant effect on the particle concentrations in the surrounding region. Both mass and number concentrations of particles exhibited maximum values immediately near the barbecue grills and often reached a peak at a distance of 10 to 15 m. The removal efficiency of a range hood for the cooking particles was tested in an indoor kitchen. The range hood effectively cleaned the particulate matter pollution caused by cooking with a removal efficiency larger than 80%. Therefore, the use of a range hood is recommended for outdoor barbecue restaurants coupled with a smoke purifier to clean the emitted high concentrations of particles.

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Single particle analysis of ambient aerosols in Shanghai during the World Exposition, 2010: two case studies

ATSI Model 3800 aerosol time-of-flight mass spectrometer (ATOFMS) was deployed for single-particle analysis in Shanghai during the World Exposition (EXPO), 2010. Measurements on two extreme cases: polluted day (1st May) and clean day (25th September) were compared to show how meteorological conditions affected the concentration and composition of ambient aerosols. Mass spectra of 90496 and 50407 particles were analyzed respectively during the two sampling periods. The ART-2a neural network algorithm was applied to sort the collected particles. Seven major classes of particles were obtained: dust, sea salt, industrial, biomass burning, organic carbon (OC), elementary carbon (EC), and NH₄-rich particles. Number concentration of ambient aerosols showed a strong anti-correlation with the boundary layer height variation. The external mixing states of aerosols were quite different during two sampling periods because of different air parcel trajectories. Number fraction of biomass burning particles (43.3%) during polluted episode was much higher than that (21.6%) of clean time. Air parcels from the East China Sea on clean day diluted local pollutant concentration and increased the portion of sea salt particle dramatically (13.3%). The large contribution of biomass burning particles in both cases might be an indication of a constant regional background of biomass burning emission. Mass spectrum analysis showed that chemical compositions and internal mixing states of almost all the particle types were more complicate during polluted episode compared with those observed in clean time. Strong nitrate signals in the mass spectra suggested that most of the particles collected on polluted day had gone through some aging processes before reaching the sampling site.     

北京市大气PM2.5中四种水溶性阴离子的水平变化比较

了解北京市城区和郊区大气细颗粒物中的四种水溶性阴离子F-、Cl-、SO42-、NO3-的浓度水平,并分析影响其水平高低的因素。使用聚四氟乙烯滤膜分别采集北京市城区和郊区大气中的PM2.5,用纯水提取后采用离子色谱法测定水溶性阴离子质量浓度。采样期间北京市大气PM2.5、F-、Cl-、SO42-和NO3-质量浓度几何均数分别为55.36、0.02、0.46、6.72和1.09μg·m-3,四种水溶性阴离子质量浓度总和占PM2.5质量浓度的19.14%;同一季节(春季)郊区监测点大气PM2.5、SO42-和NO3-质量浓度显著高于城区监测点;城区大气PM2.5与四种水溶性阴离子质量浓度秋季高于春季,但差异无统计学意义;大气PM2.5与Cl-、SO42-和NO3-质量浓度均高度相关。Cl-、SO42-、NO3-是北京市大气PM2.5的重要组成成分。     

北京市大气PM_（2.5）中四种水溶性阴离子的水平变化比较

了解北京市城区和郊区大气细颗粒物中的四种水溶性阴离子F-、Cl-、SO42-、NO3-的浓度水平,并分析影响其水平高低的因素。使用聚四氟乙烯滤膜分别采集北京市城区和郊区大气中的PM2.5,用纯水提取后采用离子色谱法测定水溶性阴离子质量浓度。采样期间北京市大气PM2.5、F-、Cl-、SO42-和NO3-质量浓度几何均数分别为55.36、0.02、0.46、6.72和1.09μg·m-3,四种水溶性阴离子质量浓度总和占PM2.5质量浓度的19.14%;同一季节（春季）郊区监测点大气PM2.5、SO42-和NO3-质量浓度显著高于城区监测点;城区大气PM2.5与四种水溶性阴离子质量浓度秋季高于春季,但差异无统计学意义;大气PM2.5与Cl-、SO42-和NO3-质量浓度均高度相关。Cl-、SO42-、NO3-是北京市大气PM2.5的重要组成成分。     

Dry deposition and particle size distributions of nitrate and sulfate in ambient air

This study reports the dry deposition pollutants of anion species (NO₃ ^‐ and SO₄ ^‐2) in the Ping Tung City of Southern Taiwan. Several deposition properties are discussed in this paper. It included dry deposition flux, anion species size distribution and deposition velocities. Noll Rotary Impactor (NRI) and Microorifice Uniform Deposit Impactor (MOUDI) were used to collect ambient air coarse and fine particulate. Dry deposition plate was applied to collect particle deposition flux. Dionex 2000i/SP Ion Chromatography equipped with 4 mm AG4A‐SC and AS4A‐SC column was employed to analyze the anion species. The eluent solution is 1.8 mM sodium carbonate/1.7 mM sodium bicarbonate. The measured dry deposition flux of nitrate ranged from 0.63 to 3.96 mg/m²‐day and averaged 2.12 mg/m²‐day, while the measured dry deposition of sulfate ranged from 1.17 to 9.53 mg/m²‐day and averaged 3.92 mg/m²‐day. The particle size distribution of nitrate has bimodal particle size distributions. However, the sulfate displayed uniform particle size distribution for all four sampling sites. Mean cumulative fraction (F%) of nitrate in the particle size range below 1, 2.5, 10 and 25 μm, in sequence, were 34.6%, 60.9%, 91.0% and 97.6%, respectively. However, the mean F% of sulfate in the particle size range below 1, 2.5, 10 and 25 um, in sequence, were 57.3%, 82.6%, 90.3% and 98.0%, respectively. The sulfate has more F% in the submicron particles. The mean MMD _o of nitrate and sulfate are 2.35 and 0.87 μm, respectively. The mean dry deposition velocities of nitrate and sulfate are 0.45 and 0.38 cm/sec, respectively.     

Extinction and Colonization of Birds on Habitat Islands

Abstract: We used point-count and transect surveys to estimate the distribution and abundance of eight scrub-breeding bird species in 34 habitat fragments and the urban matrix in southern California. We then calculated local extinction and colonization rates by comparing our data with surveys conducted in 1987. We classified factors that influence extinction and colonization rates into two types: (1) extrinsic factors, which are characteristics of the habitat fragments such as area, age, and isolation and (2) intrinsic factors, which are characteristics of the species that inhabit fragments, such as body size and population density. Over the past decade, at least one species went locally extinct in over 50% of the fragments, and local extinctions were almost twice as common as colonizations. Fragment size and, to a lesser extent, fragment age were the most important extrinsic factors determining extinction and colonization. Density indices of scrub birds were the most important intrinsic factors determining extinction rates, predicting the number of sites occupied, the probability of local extinction, relative area requirements, and time to local extinction.     

光子相关光谱（PCS）在无机高分子絮凝剂形态表征中的应用

本文运用现代先进的微粒检测手段光子相关光谱对常见的两类无机高分子絮凝剂的形态进行了表征。实验结果表明：在所测聚合氯化铁溶液中，体系呈较为单一的集中分布，由平移扩散系数计算得到平均有效直径在５－１１ｎｍ左右。在所测聚合氯化铝溶液中，主要为双峰分布，熟化后样品约为２－５ｎｍ的小颗粒与数十ｎｍ以上分布较宽的聚集体，另外，本文对光子相关光谱在形态表征中的优缺点及其它应用的可能性也作了一定的论述。     

排水管道内不同粒径沉积颗粒物冲刷率的分析与计算

为探究和量化在水流冲刷下,排水管道中不同粒径颗粒物冲刷沉积的过程,本文模拟排水管道内沉积颗粒的冲刷过程.冲刷过程中,粒径较小的悬移质颗粒(小于0.1 mm),在管道沿线取样测得水流中悬浮固体质量浓度(SS);粒径较大的推移质颗粒(0.1—2 mm),测得管道沿线不同位置沉积的颗粒质量.并建立两个数学模型分别计算排水管道内两类颗粒物的冲刷率.研究发现,悬移质颗粒,以水流中SS为依据,可计算出输送通量和冲刷率;推移质颗粒,以管道不同位置沉积下来的颗粒质量为依据,拟合出了管道中的沉积分布函数,是以e为底数的指数函数,可计算出冲刷量和冲刷率.模型计算出的冲刷率呈现出规律性:悬移质颗粒被冲刷成悬浮状态,随水流迁移过程中部分会再次沉积,使得悬移质颗粒的冲刷率从管道前段至中后段逐步降低,如初始沉积质量为100 g的0.045 mm悬移质颗粒,在0.30 m·s^-1的冲刷流速下,计算出管道前段冲刷率为78.94%,最终在管道后段降至13.89%;对于两类颗粒而言,颗粒物粒径越小,冲刷流速越大,初始沉积质量越小,冲刷率越高.     

Development of a cloud condensation nuclei (CCN) counter using a laser and charge-coupled device (CCD) camera

A continuous flow streamwise thermal gradient cloud condensation nuclei (CCN) counter with an aerosol focusing and a laser-charge-coupled device (CCD) camera detector system was developed here. The counting performance of the laser-CCD camera detector system was evaluated by comparing its measured number concentrations with those measured with a condensation particle counter (CPC) using polystyrene latex (PSL) and NaCl particles of varying sizes. The CCD camera parameters (e.g. brightness, gain, gamma, and exposure time) were optimized to detect moving particles in the sensing volume and to provide the best image to count them. The CCN counter worked well in the particle number concentration range of 0.6–8000 #·cm^-3 and the minimum detectable size was found to be 0.5 μm. The supersaturation in the CCN counter with varying temperature difference was determined by using size-selected sodium chloride particles based on K?hler equation. The developed CCN counter was applied to investigate CCN activity of atmospheric ultrafine particles at 0.5% supersaturation. Data showed that CCN activity increased with increasing particle size and that the higher CCN activation for ultrafine particles occurred in the afternoon, suggesting the significant existence of hygroscopic or soluble species in photochemically-produced ultrafine particles.     

杭州城市及其边缘区湿地磷化学特征的研究

对杭州城市及其边缘区湿地土壤的磷形态组成、固磷能力和释放潜力等方面进行了初步的研究。结果表明,杭州城市及边缘地区的湿地由于受人类影响的不同及所处环境的差异,性质已有很大的分异。城区的西湖、水塘和河流底泥中磷的积累、磷的饱和度和零吸附磷平衡浓度均明显高于城市边缘地区的湿地;湿地土壤中的磷主要呈不稳定、或亚稳定态,可提取态磷约占总磷的80%,62%的湿地土壤磷饱和度在25%以上。最大磷吸附量的大小主要与湿地中无定形氧化铁、铝含量有关。零吸附时磷的浓度(EPC)较高,在0.10~2.48mg·L-1之间,具有较强的释放潜力。半透膜渗析法测得的磷释放量与磷积累呈正相关,但当磷饱和度超过25%时,其磷释放量显著增加。研究表明杭州市及其边缘区湿地土壤磷已普遍达到较高水平,这在一定程度上影响磷净化功能的正常发挥。     

Effects of molecular weight and concentration of carboxymethyl cellulose on morphology of hydroxyapatite nanoparticles as prepared with one-step wet chemical method

Nano-sized apatite particles (nAP) synthesized with carboxymethyl cellulose (CMC) have shown great application potentials in in situ heavy metal remediation. However, differences in CMC’s properties effects on the size of nAP produced are not well understood. In this paper, two types of CMC, with respective molecular weights (MW) of ～120000 and ～240000 Dalton or respective polymerization degrees of 500 (CMC-500) and 1050 (CMC-1050), were studied in a concentration range of 0.05%–0.5% (w/w) for nAP synthesis. Morphology of the particles was characterized with transmission electron microscopy (TEM). Results showed that 0.05% CMC-500 solution gave an average particle size of 148.7±134.9 nm, 0.25% CMC-500 solution produced particles of 21.8±20.4 nm, and, 0.5% CMC-500 solution contained particles of 15.8±7.7 nm. In comparison, 0.05% CMC-1050 solution produced nanoparticles of 6.8±3.2 nm, 0.25% CMC-1050 produced smaller nAP of 4.3±3.2 nm, and 0.5% CMC-1050 synthesized the smallest nanoparticles in this study, with an average diameter of 3.0±2.1 nm. Chemical composition of the products was identified with X-ray diffraction (XRD) as pure hydroxyapatite. Interactions between nAP and CMC were discussed with help of attenuated total reflection Fourier transform infrared (ATRFTIR) spectroscopic data. This study showed that CMC at higher concentration as well as higher MW facilitated to produce finer nanoparticles, showing that nAP size could be manipulated by selecting appropriate CMC MW and/or applying appropriate CMC concentration.     

PM<Subscript>10</Subscript> emissions from industrial coal-fired chain-grate boilers

Industrial coal-fired boiler is an important air pollutant emission source in China. The chain-grate boiler is the most extensively used type of industrial coal-fired boiler. An electrical low-pressure impactor, and a Dekati® Low Pressure Impactor were applied to determine mass and number size distributions of PM₁₀ at the inlet and the outlet of the particulate emission control devices at six coalfired chain-grate boilers. The mass size distribution of PM₁₀ generated from coal-fired chain-grate boilers generally displays a bimodal distribution that contains a submicron mode and a coarse mode. The PM in the submicron mode for burning with raw coal contributes to 33% ± 10 % of PM₁₀ emissions, much higher than those for pulverized boilers. And the PM in the submicron mode for burning with briquette contributes up to 86 % of PM₁₀ emissions. Multiclones and scrubbers are not efficient for controlling PM10 emission. Their average collection efficiencies for sub-micron particle and super-micron particle are 34% and 78%, respectively. Operating conditions of industrial steam boilers have influence on PM generation. Peak of the submicron mode during normal operation period is larger than the start-up period.

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焦作市大气颗粒物中水溶性砷的分布特征

利用原子荧光法对焦作市春、夏、秋、冬四季不同粒径大气颗粒物中水溶性重金属砷的分布特征及时空变化进行分析研究。研究表明：焦作市水溶性砷主要富集在PM2.1中,且颗粒物粒径越小,其富集砷的能力就越强,各级颗粒物中4级、5级、6级（0.41～2.1μm）范围内砷的含量最高,其总含量约为5.71～19.96 ng/m3,三者在不同月份所占比例高达73%～86%;由于形成机制与影响条件不同,不同粒径大气颗粒物中砷表现出明显的季节变化特征,总体趋势为冬季〉秋季〉夏季〉春季,主要原因为冬、夏季燃煤量增加,春季大气污染源减少,地表植被覆盖密集,空气环境质量较好;燃煤是焦作大气中砷的主要来源之一,且其对大气细颗粒物（粒径≤2.1μm）中砷的贡献最明显。     

New particle formation observed from a rain shadow region of the Western Ghats,India

Abstract

This study reports on new particle formation (NPF) and characteristic features observed from a rural site falling in the rainshadow of the Western Ghats in peninsular India. A total of 35 NPF events observed during August 2018 - January 2019 are classified and analyzed here. The apparent formation rates ranged from 0.2 to 10.0?cm^–3 s^–1, while the growth rates of nucleation mode particles ranged from 1.2 to 13.8?nm h^–1. The frequency of occurrence was least during August (core monsoon) and highest during post-monsoon. The local winds were calm and southeasterly to easterly (from the urban centre) supplying the essential precursor gases during October and November, leading to a frequent occurrence of nucleation events. Observations suggest that an increased condensation sink could limit the NPF while promoting Aitken mode growth. The newly formed particles accounted for about 10–80% of the total aerosol concentration. These newly formed particles were able to act as cloud condensation nuclei after growing to approximately 50?nm with an average activation fraction of 0.4.     

杭州城市区域土壤性状的空间变异

以浙江省杭州市城区为研究对象,通过栅格取样,对研究区内40个样点的土壤性状进行调查,利用地理信息系统(GIS)和地统计学方法对杭州市区土壤性状的空间异质性和格局分布进行了初步研究.研究结果表明:杭州市城区土壤的空间异质性明显,统计变异的大小顺序依次为土壤湿度(SM)＞土壤电容率(Eb)＞土壤温度(ST)＞土壤毛细水导电...     

Beijing's coordinated development of population,resources, environment,and economy

Since the Olympic Games will be held in Beijing at 2008, the urban development plan of Beijing deserves special attention. The essence of regional sustainable development is that population (P), resources (R), environment (E) and economy (E) could develop with sustenance, order and coordination during a certain period, which forms a complex system called the PREE complex system. For this system, a multi-objective integrated model is formulated and solved by a nonlinear goal programming technique. Beijing's PREE complex system is then used as an empirical study. Twelve interesting goals are carefully selected, the parameters of each goal function were estimated by using Beijing's 50-year (1949–1999) statistical data, and their ideal goal limits for 2000 and 2005 are chosen according to the 9th and 10th Five-Year Economic Development Plans of Beijing. The results showed that population size is the most sensitive element in Beijing's PREE complex system. Furthermore, some suggestions related to public policies about the urban development of Beijing are proposed.