Deposition and Storage of Spheroidal Carbonaceous Fly-Ash Particles in European Mountain Lake Sediments and Catchment Soils

Spheroidal carbonaceous particles(SCPs) are produced only from high temperaturecombustion of fossil-fuels. In mountain lakesystems, they provide an unambiguous indicator ofatmospheric deposition. In order to comparedepositional fluxes of SCPs between mountainareas experiencing various pollutant regimes,intensive bulk deposition sampling was undertakenat five sites across Europe. Catchment soil coresand lake sediment cores were also taken at eachsite to compare SCP storage over the post-industrial period. Atmospheric, sediment and soilSCP data showed similar patterns. Highestcontamination was found in Scotland, Slovakia andSpain with the Austrian site intermediate and themid-Norwegian site least contaminated. A highproportion of accumulated SCPs were found to bestored in catchment soils at each site.Therefore, a significant increase in soilerosion, possibly as a result of future climatechange, could lead to the input of largequantities of catchment stored SCPs and, byimplication, other atmospherically depositedcontaminants to the lake ecosystem.     

管式电除尘器"伞形罩"结构特性研究

在高温、高湿窑炉烟气条件下,采用立式管式电除尘器“伞形罩”结构,能够解决其清灰不力、二次扬尘、除尘效率不稳定等问题。本研究了“伞形罩”结构的除尘机理及效率及清灰力度影响因素、抑制二次扬尘机制。研究结果表明,“伞形罩”结构除尘效率因集尘表面积的增加而提高;应用支铁框架式振打方式,振打强度明显加强;其分流机制能有效地抑制二次扬尘：从而为“伞形罩”结构的优化设计提供了依据。     

Production of radioactive particles for use in environmental studies

This paper presents an aerosol generation technique developed to produce dry aerosol particles of various sizes from aqueous solutions of salt. The technique was tested with sodium chloride, lithium carbonate and uranyl acetate at various aqueous concentrations which produced particles in the size range of 0.13-1.37 microm Mass Median Diameter (MMD). The generated aerosols were acceptably monodisperse with a geometric standard deviation of 1.4-2. Both MMD and Mass Median Aerodynamic Diameter (MMAD) increased significantly (p<0.001) with increased concentration of the salt in solution. The technique can also be used to generate aerosols of different chemical species. The results obtained indicate that the system is convenient for use with various aerosol-forming materials, with a stable particle size distribution being maintained for a long period of steady operation. The technique was successfully applied in wind tunnel studies to simulate the release of submicron radioactive particles and their interception by crops, grass and tree canopies. The relevance and application of the technique in other areas of environmental assessment studies is discussed.     

沈阳市大气可吸入颗粒物水溶性组分的因子分析

选取沈阳市6个监测点位,采集2005年冬、春、夏、秋大气可吸入颗粒物样本。用安捷伦7500型电感耦合等离子体质谱仪分析PM10中19种水溶性组分。用因子分析法分析了沈阳市大气可吸入颗粒物水溶性组分的来源。     

典型可燃物燃烧烟尘物化特性差异性研究

开展对典型可燃物燃烧烟尘的物化特性差异性研究,是全面了解烟尘信息的基础.基于可控条件下的燃烧试验,对典型可燃物燃烧烟尘物理特性和化学组分进行了分析.通过对比分析汽油燃烧烟尘、聚苯乙烯燃烧烟尘、ABS燃烧烟尘及柴油烟尘和正庚烷烟尘的透射电镜图片,对透射电镜图的紧凑性、复杂性及灰度值进行了深入分析,探讨了燃烧烟尘的物理差异性.利用固相微萃取-气质联用技术(SPME-GC-MS),对汽油燃烧烟尘、聚苯乙烯燃烧烟尘、ABS燃烧烟尘化学组分进行了分析和对比.通过燃烧烟尘的特征物质组分的分析,得到3种燃烧烟尘在特征物质的分布和出峰时间等方面的差异性.这些差异性可作为对烟尘来源及燃烧条件等因素判别的依据.     

土壤颗粒对纳米TiO_2悬浮稳定性作用机制的实验研究

在不含表面活性剂和含有表面活性剂两种条件下,研究了土壤颗粒对纳米TiO2(nTiO2)悬浮稳定性的影响.结果表明,土壤颗粒降低了nTiO2在水相中的悬浮稳定性.当体系中不含表面活性剂时,nTiO2在土壤大颗粒上的沉积是导致nTiO2脱稳沉淀的主要原因.在含有表面活性剂的溶液中,土壤颗粒降低nTiO2悬浮稳定性的作用变得更加明显了.一方面,表面活性剂加速了土壤颗粒本身的沉降从而增强了nTiO2在其中的沉降,另一方面,表面活性剂在土壤上的强烈吸附促进了表面活性剂-nTiO2在土壤上的沉积.扫描电镜显示,nTiO2不仅吸附在土壤大颗粒上,还会吸附在土壤小颗粒表面.3种表面活性剂中,十六烷基三甲基溴化铵(CTAB)悬浮的nTiO2与土壤颗粒共沉淀现象最明显.除了土壤对CTAB的吸附作用之外,XDLVO/DLVO能量计算显示CTAB体系中土壤颗粒与nTiO2之间存在显著第二极小值,表明nTiO2能够在第二极小值位置与土壤颗粒结合,从而与土壤颗粒一起快速沉淀.     

IKK inhibition prevents PM2.5-exacerbated cardiac injury in mice with type 2 diabetes

Epidemiological studies have found that individuals with diabetes mellitus(DM) display an increased susceptibility for adverse cardiovascular outcomes when exposed to air pollution.This study was conducted to explore the potential mechanism linking ambient fine particles(PM2.5) and heart injury in a Type 2 DM(T2DM) animal model. The KKay mouse, an animal model of T2DM, was exposed to concentrated ambient PM2.5 or filtered air for 8 weeks via a versatile aerosol exposure and concentrator system. Simultaneously, an inhibitor of IκB kinase-2(IKK-a)(IMD-0354), which is a blocker of nuclear factor κB(NF-κB)nuclear translocation, was administrated by intracerebroventricular injection(ICV) to regulate the NF-êB pathway. The results showed that ambient PM2.5 induced the increase of, NF-êB, cyclooxygenase-2(COX-2) and mitogen activated protein kinase(MAPK) expression in cardiac tissue, and that IMD-0354 could alleviate the inflammatory injury. The results suggested that the NF-êB pathway plays an important role in mediating the PM2.5-induced cardiovascular injury in the T2DM model. Inhibiting NFκB may be a therapeutic option in air-pollution-exacerbated cardiovascular injury in diabetes mellitus.     

不同养殖模式池塘沉降颗粒营养物质组成特征

2012年4~10月采用自制沉降颗粒收集装置收集主养草鱼和黄颡鱼池塘生态系统中沉降颗粒物,开展了颗粒物质的垂直沉降量以及沉降颗粒中碳氮磷等营养物质的组成及沉降通量的季节变化特征的研究。结果表明:养殖可以显著提高池塘颗粒物质的垂直沉降量,主养草鱼池塘中颗粒物质垂直沉降量显著高于主养黄颡鱼池塘(p0.01),且两种养殖模式池塘颗粒物质沉降量随着养殖时间推进有显著增加的趋势。主养草鱼的池塘中颗粒物质垂直沉降量在100.39~414.66g/(m2·d)之间变化,平均为224.46g/(m2·d),主养黄颡鱼池塘中沉降颗粒物质垂直沉降量在34.14~272.91g/(m2·d)之间变化,平均为155.18g/(m2·d)。两种养殖模式沉降颗粒的碳氮磷成分在养殖周期内的变化规律不明显但具有相似的变化趋势,主养黄颡鱼池塘沉降颗粒中TN、TC、TOC和TON的含量均比同时期主养草鱼高,且均随着养殖时间的推进,沉降颗粒中碳氮磷的总量呈增加趋势。两种养殖模式池塘沉降颗粒中的C/N比值与沉积物中的C/N比值较为接近,表明沉降颗粒与沉积物营养物质来源具有一定的相似性,同时养殖系统内养殖对象与其所处环境的相互依存和相互影响对颗粒物质的产生以及沉降具有重要作用。     

焊接工艺多源散发的高温颗粒污染物扩散特性数值模拟

为探究热工艺过程产生的热气流作用下颗粒的迁移规律,基于气固两相离散粒子模型(DPM)对多源浮射流伴生的高温颗粒的扩散特性进行了数值研究,讨论了两相流运动过程中热气流与颗粒群的温度和速度的瞬时变化情况.结果表明,对于473K£T₀£673K的高温颗粒群,温度衰减趋势类似,颗粒群温度分布呈中心对称;当5μm£d_p£20μm时,颗粒与气流之间的跟随性随着粒径的增大而降低;热羽流随时间经历了独立发展和相互合并的过程,羽流之间涡旋结构的消失导致中心位污染源散发的d_p=10μm的颗粒更容易发生沉降.     

Characterization of submicron aerosol particles in winter at Albany, New York

A thorough understanding of chemical composition, particle pH, and pollutant emissions is essential to address the climate and human health effects of atmospheric particles. In this study, we used a High-Resolution Time-of-Flight Aerosol Mass Spectrometer(HR-ToF-AMS)and Scanning Mobility Particle Sizer(SMPS) to characterize the composition of submicron particles. Moreover, we applied the ISORROPIA-II model to analyze the particle acidity effect on the compositional characterization of submicron ...