噪声不同高度的分布规律探讨

1 实验 淮安市环境监测站开展了固定和流动噪声源在不同距离,对不同高度建筑物影响的噪声监测,监测点设在该市淮海国际大酒店各楼层临近阳台的窗口,共设置7个监测点,监测点距离地面高度(垂直高度)分别为1.5 m、12 m、17 m、23 m、30 m、35 m、42 m.监测方法按照GB/T 14623-1993<城市区域环境噪声测量方法>和<环境监测技术规范>(噪声部分),监测仪器为噪声积分统计分析仪.固定声源监测频次:监测4次,每次测10 min,以等效声级(Leq)值参加统计;复合声源按功能区测量方法监测,监测4次,每次为24 h连续监测,测量每小时的Leq值,实测20 min,Leq值参加统计,同时记录车流量.噪声监测点见图1.     

尾矿库水质实时监控系统设计与实现

设计并实现了一种基于无线传输GPRS技术尾矿库水质实时监控系统;该监控系统由监测传感器、变送器、模拟量测量模块、GPRS无线监控终端、监测服务器及监测软件、浮标装置、电源系统等构成。系统监控点分布在尾矿库的不同区域,监控点布设浮标并配置有监测传感器,变送器把来自传感器的基准信号经放大后输出相对应的4~20m A恒流电流信号,模拟量测量模块测量4~20m A信号并以RS-485标准接口通讯输出,信号通过GPRS无线监控终端系统传递给监测服务器;通过安装在监测服务器中的基于B/S模式监测软件实现监测数据的保存、查询、打印、报警等功能。通过该系统应用,可以方便快捷的监测尾矿库水质p H变化情况,对在役尾矿库水域污染控制、运行管理、水质分析提供了有益参考。     

连续采样实验室分析法监测结果偏低的原因

实验部分 (一)、分析方法:按《环境监测分析方法》要求进行。 (二)、实验方法: 1.进行实地监测:在同一监测点,同时采用间断采样和连续采样对大气环境中的二氧化硫及氮氧化物进行同步实地监测。其中,间断采样时间分别在每天7.11.15及19时,采样流量分别为0.5L/min(SO_2)及0.3L/min(NO_x),采样时间均为30分钟。连续采样,采样时间为24小时,采样流量在0.2L/min左右。吸收瓶温度控制在15±3℃。     

道路交通噪声最佳测量时间和时段研究

对典型城市主干道进行长期噪声监测,对监测结果进行误差分析,得出城市主干道交通噪声短时间测量最佳时间及时段,提高工作效率的同时提高数据准确度。     

夜间建筑施工噪声扰民测量时间探讨

通过对现有夜间建筑施工噪声测量方法关于测量时间及国家和深圳经济特区有关夜间施工规定的分析,阐述了夜间施工噪声扰民监测时间问题。     

基于正交试验方法的化学需氧量测定影响因素分析

参照《水质化学需氧量的测定重铬酸盐法》(HJ 828—2017)标准,设计出三水平四因素正交试验方案,考察水样体积、消解温度、消解时间和硫酸银-硫酸溶液加入量对化学需氧量(COD;)测量值的影响。研究表明:测定COD_(Cr)质量浓度>50 mg/L的样品时,影响COD;测定值的主次因素排序为:水样体积、硫酸银-硫酸溶液加入量、消解时间和消解温度;COD_(Cr)测定的最优试验条件为:水样体积5 m L、消解温度200℃、消解时间90 min、硫酸银-硫酸溶液加入量10 m L。与《HJ 828—2017》标准中的监测条件相比,该方法分析时间更短、加入的硫酸银-硫酸溶液体积更少,在应急监测中具有更高的参考价值。     

噪声监测应注意的问题

阐述了噪声监测中监测点位的科学设置、测量时间和监测仪器的合理安排 ,以及怎样正确地把握评估标准。     

兰州市空气中微生物采样时间的优化研究

在兰州市选取环保科技大厦室内和室外进行微生物气溶胶取样,研究室内、外环境的微生物气溶胶最佳采样时间,为下一步研究兰州市城区不同季节及各功能区空气微生物气溶胶污染特征奠定基础。结果表明,室内细菌气溶胶最佳采样时间为9min,真(霉)菌气溶胶和放线菌气溶胶最佳采样时间均为7min;室外细菌气溶胶和真(霉)菌气溶胶最佳采样时间均为25min,放线菌气溶胶最佳采样时间为20min。     

噪声监测中存在问题的探讨

阐述了噪声监测中存在的问题，对监测点位的科学设置、测量时间和监测仪器的合理安排、如何正确地把握评估标准等作了探讨。     

吹扫捕集-气相色谱/质谱法测定水中的乙醛、丙烯醛、丙烯腈和吡啶

水中的乙醛、丙烯醛、丙烯腈和吡啶经吹扫捕集、解吸后,用HP-VOC毛细管色谱柱进行GC分离,用GC-MS法选择离子模式(SIM)下进行检测,外标法定量。结果表明,选择取样量25 m L,吹扫流量为40 m L/min,吹扫温度为40℃,吹扫时间为15 min,解吸时间为2 min,解吸温度为200℃,烘焙时间20 min,乙醛和吡啶质量浓度在0.025~0.60 mg/L之间,丙烯醛和丙烯腈质量浓度在0.002 5~0.10 mg/L之间时,校准曲线呈线性关系,相关系数r0.995,乙醛、丙烯醛、丙烯腈和吡啶的方法检出限分别为0.001 6,0.001 3,0.000 5和0.002 1 mg/L。对3个不同浓度样品进行空白加标实验,测量的回收率为87.8%~114.3%,相对标准偏差(n=6)为2.51%~10.4%。对3批实际水样进行分析,其中一个废水水样加标回收率为79.2%~103.8%,相对标准偏差(n=6)为3.04%~6.39%。     

Measurement instability and temporal bias in chemical soil monitoring: sources and control measures

Concern that human impacts on the environment may be harmful to natural resources such as soils as well as to living conditions is the major motivation for long-term environmental monitoring. However, the evidence that measurement bias is not constant through time affects time series as an artifact; this also holds true for chemical soil monitoring. Measurement instabilities occur along the whole measurement chain, from soil sampling to the expression of results. The first step in controlling measurement instability is to identify its relevant sources, and the second is to control it by stabilizing, minimizing, or quantifying measurement instability. For all five steps in the measurement process, from soil sampling to the expression of the analytical results, sources of measurement instability are identified and measures of control discussed, leading to the main conclusion concerning the requirement to continuously control the relevant environmental and measurement boundary conditions that may affect measurement instability. The innovative aspect of this paper consists in explicitly addressing measurement instability in chemical soil monitoring and tracking it along the whole measurement chain. The paper is also a plea for a change of paradigm in long-term environmental monitoring, namely to consider temporal measurements as unstable unless their degree of stability is traceably demonstrated, adequately quantified, and included in interpretation.     

机场周围飞机噪声测量的影响因素分析

简要回顾了机场周围飞机噪声的测量方法、评价指标;针对测量过程中存在的问题,从测量周期、飞行架次分布、机型的代表性、环境背景噪声等几个方面考察了对测量数据的影响,对机场周围飞机噪声测量的影响因素进行了分析;论证了缩短测量周期的可行性,当每天的飞行架次在200架左右时,以3 d取代7 d的做法较为可行;对于飞机噪声测量过程中存在的问题,提出了个人看法和建议。     

浅谈环境监测化学测量结果的计量溯源性

确保测量结果的计量溯源性是保障数据有效性的基本要求。为此,国家明确提出要建立健全国家生态环境监测量值溯源体系。化学测量是环境监测工作中最常用的一种测量方式。由于基体、浓度等的影响往往比较复杂,如何确保环境监测化学测量结果的计量溯源性成为环境监测领域的重要研究内容。通过总结建立环境监测化学测量结果计量溯源性的途径,对环境监测分析方法标准、国家环境标准样品、环境检测能力验证等在保证环境监测化学测量结果计量溯源性中的作用进行了分析,以期为环境监测化学测量结果计量溯源性的建立提供参考。     

On-line solid phase extraction with polyurethane foam: trace level spectrophotometric determination of iron in natural waters and biological materials

This paper reports the development of a simple and accurate on-line procedure for preconcentration and determination of dissolved iron in waters and biological materials using unloaded polyether-type polyurethane foam as solid extractor. In the developed flow injection system, the analyte was preconcentrated from acidic aqueous medium as iron-thiocyanate complex with post-elution with ascorbic acid solution and spectrophotometric measurement with 1,10-phenanthroline as colorimetric reagent. In order to improve the performance of the system several chemical and flow variables were investigated as well as the effect caused by the presence of possible interferents. The method was validated by the analysis of two certified reference materials. Application of the methodology was carried out by the determination of dissolved iron content in eight natural water samples with different characteristics. The results were compared with those obtained by electrothermal atomic absorption spectrometry (ETAAS) and no statistical difference was observed. The detection limit was 0.75 microgram l-1 and the RSD was 1.2% for 2 min preconcentration time. At this condition, a productivity of 20 samples h-1 was achieved. Increasing the preconcentration time up to 3 min, a detection limit of 0.45 microgram l-1, an RSD of 1.5% and an analytical throughput of 15 h-1 were verified.     

Measurement of total antimony and antimony species in mine contaminated soils by ICPMS and HPLC-ICPMS

This paper describes the measurement of total antimony and antimony species in "real world" mine contaminated sediments using ICPMS and HPLC-ICPMS. Low and high temperature microwave extraction procedures (90 degrees C and 150 degrees C, respectively) using a range of nitric-hydrochloric acid combinations were examined as to their efficacy to extract antimony from six mine contaminated soils and a certified reference material. The use of the higher temperature with nitric-hydrochloric acid (1:2 (v/v)) was suitable to release antimony from sediments and the certified reference material, NIST 2710 Montana soil. Antimony concentrations obtained using this acid mixture were similar to those obtained using a more aggressive extraction with nitric, hydrochloric, perchloric and hydrofluoric acid mixture. A 25 mM citric acid solution at 90 degrees C for 15 min extracted 47-78% of antimony from soils. A Hamilton PRP X-100 anion exchange column with 20 mM EDTA mobile phase, pH 4.5, flow rate 1.5 mL min(-1) and column temperature of 50 degrees C was used to separate antimony species. Column recoveries ranged from 78-104%. The predominant form of antimony was Sb(5+). Little conversion of Sb(5+) occurred (<5%) during extraction, however, significant conversion of Sb(3+) occurred (approximately 36%). The extraction of antimony species with citric acid should be useful in the determination of inorganic antimony available to plants, as plants commonly excrete carboxylic acids, including citric acid, into their rhizospheres to mobilise trace elements for nutritional purposes.     

运用线性拟合法评定水中总磷的测量不确定度

采用Top—Down不确定度评定理念，利用实验室日常质控数据，结合标准样品的线性校准方法（线性拟合法），评定水中总磷的测量不确定度，并将评定结果与GUM评定法相比较，相对偏差≤20％。指出线性拟合法适用于测量系统校准函数成线性，且实验总残差符合常数剩余标准差假定情况下的不确定度评定。     

稀释倍数法测定污水色度的方法

研究选择了有代表性的6种色调的污水样品为研究对象,系统比较了不同色调、不同人员、不同稀释方法对测定结果的影响。选用红、橙、黄、绿、蓝、紫6种不同色调的样品进行测定,绿色、蓝色和黄色的测定结果分散在2个倍数之间,其中绿色的集中度高达84%。红色、橙色、紫色分散在3个倍数之间,紫色的集中度高达100%。对比自然倍数稀释法、偶数倍稀释法和2n倍稀释法,这3种方法同时测定红色调的样品,其测定结果的区间是相同的,集中区域内的人员分别占总人数的71%、83%和94%。结果表明:用1名实验人员使用自然倍数稀释法对样品进行单次分析作为色度测定的方法是有效的。     

Measurement of the proximity effect for indoor air pollutant sources in two homes

Personal exposure to air pollutants can be substantially higher in close proximity to an active source due to non-instantaneous mixing of emissions. The research presented in this paper quantifies this proximity effect for a non-buoyant source in 2 naturally ventilated homes in Northern California (CA), assessing its spatial and temporal variation and the influence of factors such as ventilation rate on its magnitude. To quantify how proximity to residential sources of indoor air pollutants affects human exposure, we performed 16 separate monitoring experiments in the living rooms of two detached single-family homes. CO (as a tracer gas) was released from a point source in the center of the room at a controlled emission rate for 5-12 h per experiment, while an array of 30-37 real-time monitors simultaneously measured CO concentrations with 15 s time resolution at radial distances ranging from 0.25-5 m under a range of ventilation conditions. Concentrations measured in close proximity (within 1 m) to the source were highly variable, with 5 min averages that typically varied by >100-fold. This variability was due to short-duration (<1 min) pollutant concentration peaks ("microplumes") that were frequently recorded in close proximity to the source. We decomposed the random microplume component from the total concentrations by subtracting predicted concentrations that assumed uniform, instantaneous mixing within the room and found that these microplumes can be modeled using a 3-parameter lognormal distribution. Average concentrations measured within 0.25 m of the source were 6-20 times as high as the predicted well-mixed concentrations.     

海洋水质在线监测系统中硝酸盐测量方法比较

硝酸盐是海洋水质监测的重要指标,目前在海洋水质在线监测系统中搭载的硝酸盐在线分析仪的种类较多,采用的测量原理也不尽相同.选取了 3种采用不同测量方法的代表性硝酸盐分析仪[氯化钒还原比色法硝酸盐分析仪、二乙烯三胺五乙酸还原比色法(DTPA)硝酸盐分析仪、紫外分光光度法硝酸盐分析仪],结合各自的测量原理、化学试剂特性等,就...     

氮氧化物检测结果可靠性影响因素研究

针对氮氧化物检测时分析方法及结果可能出现的问题进行了讨论,并对其可靠性进行了验证。以氮氧化物分析仪(化学发光原理)检测氮氧化物(NO_x)为例,分别对是否校准、定值标准的选择及不同工作模式3种情况下氮氧化物浓度测量结果的可靠性及影响因素进行评价,并用另外一种不同工作原理的傅里叶红外变换光谱法进行结果确认。结果表明:氮氧化物分析仪以自动模式进行工作时,不进行校准很可能得到完全错误的分析结果;浓度合适的标准物质的选择有利于提高分析结果的准确度。