我国大气尘计数浓度水平

介绍了近年来对涵盖我国各省区(港、澳、台除外)132个地区大气尘计数浓度的测定数据,结果表明除一例外浓度均在30万粒/L以下,比20余年前明显降低.     

高效过滤器大气尘检漏浓度的研究——国标《洁净室施工及验收规范》编制组研讨系列课题之五

实测了人扎针孔0.6 mm和1.0 mm时高效过滤器对于大气尘的泄漏浓度,当上游大气尘浓度只有300～400粒/L时,下游仍可测出5～10粒/L的泄漏.     

城市公园大气颗粒物浓度的节假日特征

以杭州西湖风景区花港观鱼公园为研究对象,对比分析节假日与非节假日公园内大气颗粒物(PM_(2.5)、PM_(10))浓度与游客量、气象因子、植物群落类型的相关性,并从宏观—中观—微观3个层次探究花港观鱼公园大气颗粒物浓度的节假日特征,为城市公园的科学建设提供参考和依据。研究发现:大气颗粒物浓度有明显的节假日效应。宏观方面,杭州主城区元旦节期间大气污染物主要是PM_(2.5)和PM_(10),节日期间的平均浓度分别为102±41.51μg.m~(-3)、155±64.86μg.m~(-3),分别是非节日的1.6倍、1.7倍。杭州主城各区受节日影响较大的是余杭区、萧山区和下城区。中观方面,花港观鱼公园节日期间PM_(2.5)和PM_(10)有波峰现象且振幅剧烈呈锯齿状;非节日期间午后出现波谷,上下振幅较小,其影响因子特征表现为:节日期间游客量与大气颗粒物浓度相关性较高,游客游览观光活动对PM_(10)的贡献率更大;气象因子对PM_(10)的影响比PM_(2.5)显著。微观方面,公园内3种不同植物群落类型绿地的PM_(2.5)浓度表现为:密林纯林草坪。     

棉纺车间颗粒物浓度及粒径分布特征研究

通过实地监测,针对不同车间的棉尘颗粒物的浓度及粒径分布特征进行了对比分析,监测结果表明:清花,梳棉及细纱车间的平均总颗粒物浓度分别为3.65 mg/m 3、2.87 mg/m 3、1.75 mg/m 3,均大于棉尘接触限值.由前纺工艺至后纺工艺,总颗粒物浓度呈逐渐减小的趋势,清花车间总颗粒物浓度是细纱车间浓度的2.08...     

城市植被对大气颗粒物的防控功能及应用

大气颗粒物污染日益严重,而利用城市植被防控颗粒物,是缓解大气污染的重要途径之一。作者阐述了植被滞尘过程,归纳论述了滞尘功能的主要影响因素及区域尺度上量化植被滞尘贡献的模型,指出关注颗粒物从大气到叶片的迁移沉降过程和影响因素是提高城市植被滞尘功能的突破点。     

2013—2014年我国大气污染物的时空分布特征及SO_2质量浓度年代际变化

为了解我国大气污染物在不同季节的时空分布特征,统计并分析了20世纪80年代—21世纪10年代中国环境监测总站发布的大气污染物质量浓度监测资料。结果表明:2013年11月—2014年10月PM2.5和SO_2全国平均质量浓度的季节变化较明显,冬季浓度最高;同期各个季节我国北方城市PM2.5和SO_2平均质量浓度明显大于南方,冬季最显著,但1984年和1994年则表现为南方城市SO_2平均质量浓度高于北方城市。1984年、1994年、2014年这3年相比较,SO_2全国平均质量浓度逐年降低。工业排放、取暖季燃煤以及不同地区的局地地理环境、经济发展状况、能源结构、空气污染防治、气象条件的差异等是区域污染特征形成的主要原因。     

动车组车厢内空气颗粒物浓度实测与分析

通过对颗粒物各粒径段浓度数据处理以及耦合通风空调系统,得到了新风对颗粒物计数浓度的贡献率和客室内贡献率公式.进而分析了动车组车厢内的颗粒物粒径分布特征以及新风、客室内对颗粒物计数浓度的贡献情况.结果表明客室内颗粒物主要由PM1.0组成;颗粒物粒径越小,新风贡献率越大,随着颗粒物粒径的加大,新风贡献率逐渐减小,客室内贡献率逐渐增大.该研究结果对解决动车组车厢中可吸入颗粒物浓度控制问题、提高车厢环境空气质量具有指导作用和现实意义.     

大气CO_2浓度和温度升高对稻麦轮作系统土壤剖面甲烷分布的影响

在田间开放式空气条件下模拟未来50年后气候变化的情况,包括大气温度升高(T)和CO2浓度升高(FACE)以及二者同时升高(FACE+T)对稻麦轮作生态系统稻田土壤剖面温室气体甲烷(CH4)分布的影响。通过田间小区试验,运用土壤剖面气体原位采集系统周年观测,研究CH4在水稻-小麦轮作周期淹水或排水状态下4个不同土壤层次(0⁷cm,77cm,7¹5cm,1515cm,15³0cm,3030cm,30⁵0cm)的行为特征。研究表明:各处理的不同土壤剖面CH4的动态变化趋势相同;水稻生长季CH4浓度随着土层深度的增加而减少,各土壤剖面CH4平均浓度显著高于小麦生长期;小麦生长季CH4浓度则随着土层深度的增加而增加,而且降水显著增加了该季表层CH4浓度。与对照(CK)相比,气候变化的3个处理(FACE、T、FACE+T)均显著增加了土壤剖面各层次的CH4浓度(P<0.05),其中T处理7cm处CH4的平均浓度最高。     

Seasonal pollution characteristics of organic compounds in atmospheric fine particles in Beijing

Beijing is a rapidly developing city with severe and unique air pollution problems. Organic matter is the most abundant fraction in fine particles in Beijing, occupying 30-50% of the total mass, indicating its key role in air pollution control. However, detailed chemical characterization of particulate organic matter in Beijing has never been reported. In this study, fine particles in the urban atmosphere in Beijing were investigated for its organic components by GC/MS technique. Over 100 individual organic compounds were identified and quantified in 25 PM2.5 samples from the summer, autumn and winter of 2002-2003. Alkanes, fatty acids, dicarboxylic acids, polycyclic aromatic hydrocarbons and some important tracer compounds (hopanes, levoglucosan and steroids) were the major constituents with the sum of their concentrations of 502, 1471 and 1403 ng m(-3) in summer, autumn and winter, respectively. Different organic compounds presented apparently different seasonal characteristics, reflecting their different dominant emission sources, such as coal combustion, biomass burning and cooking emission. The abundance and origin of these organic compounds are discussed to reveal seasonal air pollution characteristics of Beijing.     

Source apportionment of fine and coarse atmospheric particles in Auckland, New Zealand

Atmospheric fine particles (with a diameter less than 2.5 microm) and coarse particles (with a diameter between 2.5 and 10 microm) were collected simultaneously at an urban background site in Auckland, New Zealand, in the summer and winter of 2003. Major water-soluble ions, black carbon (BC), and some elements in the samples were analysed, and the data compiled into two sets. Selected trace gases (NH3, HONO, HNO3, and SO2) were also collected at the same time. Application of positive matrix factorisation to the particle data resolved five sources for the fine particles and five for the coarse particles. Weighted multiple linear regression was used to investigate the mass contributions of the sources. It was found that although natural sources had significant contributions to the coarse particles, anthropogenic sources dominated the contributions to the fine particles, particularly in winter. Significant seasonal changes of the sources were observed. Overall, sea salt and wind-blown soil had significantly stronger contributions in the summer; in contrast, the winter contribution of vehicle emissions, road dust, and industry and incineration sources was significantly higher. These seasonal changes may be explained by variations in meteorological conditions and atmospheric chemistry. The nonparametric correlations between the atmospheric concentrations of the trace gases and the mass contributions of the resolved sources demonstrate that these sources are realistic, providing a useful supplementary approach for the assessment of receptor modelling.     

Chemical and microbial effects of atmospheric particles on the performance of steep-slope roofing materials

The reflectivity of a roof is a critical component in design of strategy to reduce overall building energy usage. Airborne particulate matter that settles on a roof can either reflect or absorb incoming solar radiation. The light scattering and absorption processes occur within a few microns of the surface that affects the solar reflectance of the roof. The long-term loss of roof reflectivity appears driven by the ability of the atmospheric particulate matter to cling onto the roof and resist being washed off by wind and or rain. Contaminants collected from samples of roof products exposed at seven California sites for about one and a half years were analysed for major and trace elements and carbons to assist characterization of the chemical profile of the atmospheric particles that soil each roof sample. The chemical composition of the accumulated particles was very similar across the state of California; there was no clear distinction from one region to another. Elemental carbon did not contribute significantly to the loss of solar reflectance as initially expected. Dust particles and organic carbon compensated for the loss of solar reflectance due to elemental carbon possibly because some crystalline forms of these elements were light reflecting and contributed to the solar reflectance. Differences in microbial communities and biomass were seen between the various materials. Abundance of microbial biomass on roof tiles appears to be related to the composition/surface structure of the tile. Cyanobacteria or fungi represent the dominant player.     

大气颗粒物直接进样的ICP-MS重金属实时监测系统

为实时监测大气中重金属浓度的变化,搭建并调试两套大气颗粒物直接进样的ICP-MS系统。长期监测大气中重金属的浓度变化,以测试两套系统的性能指标,对比分析与X射线荧光法测试的差异。结果表明,两套ICPMS系统在重金属浓度含量、变化趋势上有较高的一致性。两套系统的检出限均为μg/m3级,精密度均<5%,24h漂移均<2%(K, Ca除外)。大气颗粒物直接进样的ICP-MS系统的测试数据与X射线荧光法在重金属浓度变化趋势上基本一致。     

中国西南地区隧道施工事故特征分析

为探究中国西南地区(重庆、四川、贵州、云南、广西)的隧道施工事故特征,结合事故次数、死亡人数、受伤人数3项指标对2006-2016年间发生的隧道施工进行了分析.通过年度、月度、一天时间段分析研究了事故的时间特征,发现从2012开始3项指标均呈增长趋势、事故高发的月份是11月,并分析了时间因素与省区的耦合关系.依据死亡人...     

Detection of Pb-LIII edge XANES spectra of urban atmospheric particles combined with simple acid extraction

Pb-LIII edge XANES spectra of atmospheric particles are directly obtained by fluorescent XAFS spectroscopy using a 19-element solid state detector (SSD). Particulate sample was collected on a quartz fiber filter using a high-volume air sampler, and the filter was cut into small pieces (25x25 mm). Then, surface layer of the filter piece was scaled and accumulated in order to enhance the particle density per filter unit. Use of 10 pieces of the surface layer enables the measurement of Pb-LIII edge XANES spectra on beamline BL01B1 at SPring-8, Hyogo, Japan. The shape of the Pb-LIII edge XANES spectra of the particulate sample is similar to the shapes of the spectra for PbS, PbCO(3), PbSO(4) and/or PbCl(2). Additionally, the filter sample is also divided into water-soluble, 0.1 M HCl-extractable, and residual fractions of Pb compounds by a simple acid extraction procedure. We discuss the possibility of Pb speciation in the particulate samples with combination of highly sensitive XANES spectroscopy and simple acid extraction.     

Extraction of water particles from atmospheric air through a Scheffler reflector using different solid desiccants

ABSTRACT

In this article, an attempt has been made to extract water particles from atmospheric air by using silica gel, molecular sieve13× and activated alumina. The cycle consists of two phases, first is a nocturnal phase (night) and other is a diurnal phase (day time). In the nocturnal phase, adsorption process takes place, regeneration and condensation processes take place in the diurnal phase. The water production rate depends upon the regeneration rate of the material. A newly designed fixed focus Scheffler reflector of surface area 1.54?m² is used to regenerate the desiccant materials. The water produced from this method is clean and can be used for potable purposes. The production rate of water is 43, 38 and 155?ml/day from 1?kg each of the molecular sieve, activated alumina and silica gel, respectively; furthermore, the adsorption rate, regeneration rate and cost analysis are also carried out.     

我国坡缕石粘土资源分布与特征研究

根据我国坡缕石粘土资源特征、分布状况和开发现状,按苏皖、西北、华中和其他零散分布区对资源分布、储量及典型矿区资源特征进行了论述;研究内容对我国坡缕石粘土资源的综合开发利用具有参考价值,有望拓宽坡缕石的研究应用领域,创造更高的附加值.     

钢结构住宅的特点和在我国的推广应用

主要阐述了钢结构住宅自身的特点,与传统住宅结构相比具有无比的优越性,符合可持续发展战略要求,符合我国这样一个能源消耗大国对节能的要求,具有良好的经济效益,因此,在我国应大力推广应用。