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Frédériqu Larrarte 《Environmental Fluid Mechanics》2008,8(3):249-261
A precise determination of the pollutant loads processed through the sewer networks is required for legal, environmental and
management reasons. Such a determination requires a good evaluation of concentrations, which is not an easy task because samplers
or sensors can perform measurements in a cross-sectional area of only a few locations, and this local information must then
be extrapolated across the whole cross-sectional area of the sewer network. This latter step is problematical. A great deal
of attention must be given to suspended solids because they are prone to settle and display heterogeneous concentration patterns.
A two-dimensional sampler has been designed to measure the variation of suspended solids concentration throughout a cross-sectional
area. This paper presents the principles upon which the conception of this experimental device was based and the building
process. Experimental results are presented and discussed. 相似文献
115.
常用的直通式深水采样器不但价格较高,且使用不方便。本文介绍一种简单、实用的吸水式深水采样器,具有造价低廉、操作简单、方便实用的优点,尤其适用于河流湖库的深层水样采集,采水深度可达100m左右。 相似文献
116.
颗粒物再悬浮采样器研制与应用 总被引:6,自引:0,他引:6
研制了颗粒物再悬浮采样器,阐述了颗粒物再悬浮采样器的工作原理及系统结构。对颗粒物再悬浮采样器的PM10和PM2·5捕集效率以及采样时间进行了研究分析,选取了颗粒物再悬浮采样器合适的采样时间。 相似文献
117.
大气颗粒物采样器的设计与应用 总被引:2,自引:1,他引:1
自行开发设计大气颗粒物双通道采样器,通过更换粒径切割器实现对大气总悬浮颗粒物(TSP)、可吸入颗粒物(PM10)或细颗粒物(PM2.5)样品的采集。该仪器通过流量传感器、比例阀和流量控制板精确控制每个通道的采样流量,控制系统还可实时采集大气环境温度、压力、湿度、风速和风向5个气象参数,并根据环境温度、压力的变化对采样的体积流量进行补偿计算,以确保进样口体积流量恒定,保证粒径切割准确。在2011年深圳大学生运动会期间(8月12—23日)和后期(8月24日至9月4日),利用该仪器进行了大气环境野外观测实验,并对该仪器和Thermo2300采样器的结果进行了平行性分析和对比分析,其平行结果和对比结果相关系数均大于0.99。 相似文献
118.
Measurement of nitrogen dioxide using passivediffusion tube over 22 months in Cambridge, U.K. areanalysed as a function of sampler exposure time, andcompared with NO2 concentrations obtained from aco-located chemiluminescence analyser. The averageratios of passive sampler to analyser NO2 at acity centre site (mean NO2 concentration 22 ppb)are 1.27 (n = 22), 1.16 (n = 34) and 1.11 (n = 7) forexposures of 1, 2 and 4-weeks, respectively. Modellingthe generation of extra NO2 arising from chemicalreaction between co-diffusing NO and O3 in thetube gave a ratio (modelled/measured) of 1.31 for1-week exposures. Such overestimation is greatest whenNO2 constitutes, on average, about half of totalNOx (= NO + NO2) at the monitoring locality.Although 4-week exposures gave concentrations whichwere not significantly different from analyserNO2, there was no correlation between thedatasets. At both the city-centre site and anothersemi-rural site (mean NO2 concentration 11 ppb)the average of the aggregate of four consecutive1-week sampler exposures or of two consecutive 2-weeksampler exposures was systematically greater than fora single 4-week exposure.The results indicate two independent and opposingsystematic biases in measurement of NO2 bypassive diffusion sampler: an exposure-timeindependent chemical overestimation with magnitudedetermined by local relative concentrations of NO andO3 to NO2, and an exposure-time dependentreduction in sampling efficiency. The impact of theseand other potential sources of systematic bias on theapplication of passive diffusion tubes for assessingambient concentrations of NO2 in short (1-week)or long (4-week) exposures are discussed in detail. 相似文献
119.
Duretz S Drouet JL Durand P Hutchings NJ Theobald MR Salmon-Monviola J Dragosits U Maury O Sutton MA Cellier P 《Environmental pollution (Barking, Essex : 1987)》2011,159(11):3162-3170
Modelling nitrogen transfer and transformation at the landscape scale is relevant to estimate the mobility of the reactive forms of nitrogen (Nr) and the associated threats to the environment. Here we describe the development of a spatially and temporally explicit model to integrate Nr transfer and transformation at the landscape scale. The model couples four existing models, to simulate atmospheric, farm, agro-ecosystem and hydrological Nr fluxes and transformations within a landscape. Simulations were carried out on a theoretical landscape consisting of pig-crop farms interspersed with unmanaged ecosystems. Simulation results illustrated the effect of spatial interactions between landscape elements on Nr fluxes and losses to the environment. More than 10% of the total N2O emissions were due to indirect emissions. The nitrogen budgets and transformations of the unmanaged ecosystems varied considerably, depending on their location within the landscape. The model represents a new tool for assessing the effect of changes in landscape structure on Nr fluxes. 相似文献
120.
Zhang Y Deng S Liu Y Shen G Li X Cao J Wang X Reid B Tao S 《Environmental pollution (Barking, Essex : 1987)》2011,159(3):694-699
Air-soil exchange is an important process governing the fate of polycyclic aromatic hydrocarbons (PAHs). A novel passive air sampler was designed and tested for measuring the vertical concentration profile of 4 low molecular weight PAHs in gaseous phase (PAHLMW4) in near soil surface air. Air at various heights from 5 to 520 mm above the ground was sampled by polyurethane foam disks held in down-faced cartridges. The samplers were tested at three sites: A: an extremely contaminated site, B: a site near A, and C: a background site on a university campus. Vertical concentration gradients were revealed for PAHLMW4 within a thin layer close to soil surface at the three sites. PAH concentrations either decreased (Site A) or increased (Sites B and C) with height, suggesting either deposition to or evaporation from soils. The sampler is a useful tool for investigating air-soil exchange of gaseous phase semi-volatile organic chemicals. 相似文献