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.     

南通市移动通信基站电磁辐射时空分布特征

为了解南通市移动通信基站电磁辐射时空分布特征,随机实测504座典型基站,着重从水平和垂直方向50 m范围内开展监测,并选取典型基站开展24 h连续监测。结果表明,南通市移动通信基站电磁辐射水平满足《电磁环境控制限值》(GB 8702—2014)中公众曝露控制限值要求;基站电磁辐射水平分布随距离增大呈现先增加后逐渐减小的趋势,地面最大投射点的距离基本为20~30 m;垂直方向最大监测值出现在与天线高度相近的楼层;24 h基站电场强度随时间呈明显变化,与话务量和数据流量分别进行相关性分析,相关系数为0.968 3和0.709 8,说明目前话务量仍是电磁辐射强度的重要影响因素。     

南京市典型快速路交通噪声监测与影响分布研究

为科学全面地开展城市道路交通噪声影响评估，更精确地服务道路交通噪声污染治理工作，选取南京市具有代表性的道路交通干线，采用手工监测和自动连续监测的方法，进行不同路段噪声污染程度及其随时间、空间变化规律的研究。结果表明，地面快速路段、高架路段以及衔接路段两侧噪声敏感建筑物受道路交通噪声影响较大，夜间均超标；相邻区域要达到2类声环境功能区昼间标准限值要求，需距离地面快速路慢车道约45 m，距离高架路段慢车道约92 m；要达到2类声环境功能区夜间标准限值要求，需距离地面快速路慢车道约175 m，距离高架路段慢车道约172 m；敏感建筑物所受噪声影响随楼层高度升高而增大，同时噪声影响情况与道路两侧建筑物密度、道路车辆行驶速度有关。建议严格道路及噪声敏感建筑物规划控制，采取阻断传声路径、受声建筑物强化保护等措施控制噪声影响。     

测点高度对道路交通噪声监测数据的影响

通过在4城市对132条道路进行了道路交通噪声测点高度试验,系统分析了测点高度从手工监测的1.2 m向自动监测的4.5 m转化后,在不同道路情况对道路交通噪声监测数据的影响。结果表明,测点高度提高后监测结果变化在±3 dB(A)以内。待测道路的车道数和测点与机动车道的距离是其主要影响因素。对两测点高度进行对比,4.5 m高度噪声值随水平距离增加衰减较小,测量结果更稳定。     

城市快速路交通噪声分布特征及污染现状

为了解快速路交通噪声的分布特征及污染现状,对城市快速路的交通噪声进行监测,结果表明,噪声随车流量的增大而升高,同时受车辆类型等其他因素的影响;随着与快速路水平距离的增大,交通噪声值呈下降趋势,特别是在距离快速路路沿前40 m内噪声衰减尤为明显;距高架道路不同水平距离处的噪声声场垂直分布规律基本一致,但距离高架道路较远处的敏感建筑物噪声值最高点楼层有所上移;快速路旁噪声敏感点交通噪声超标情况严重。     

石家庄市夏季臭氧污染近地层垂直变化特征

基于2022年6月1日—8月31日河北省石家庄市地面气象要素和臭氧（O₃）观测数据，结合O₃激光雷达垂直探测数据分析近地层O₃垂直变化特征，并利用后向轨迹聚类分析法探讨其污染来源。结果表明：（1）2022年夏季石家庄O₃污染天数为6月＞7月＞8月。影响ρ（O₃）变化的主要影响因子是气温，平均气温与ρ（O₃）正相关，相对湿度与ρ（O₃）负相关。（2）当探测高度≥2 km时，全天、日间、夜间的ρ（O₃）变化较稳定，ρ（O₃）均在100μg/m³左右。近地层ρ（O₃）差异最大，无论是日间还是夜间，ρ（O₃）均在0.3 km左右达到峰值，之后逐渐降低。6月的ρ（O₃）垂直变化速率较大，7、8月ρ（O₃）垂直变化速率逐渐降低。（3）不同垂直高度下，石家庄夏季ρ（O₃）日变化情况均成“单峰单谷”型，地面ρ（O₃）日变化波动最明显，随着高度的上升ρ（O₃）日变化情况趋于平缓。（4）后向轨迹聚类分析结果表明，距离地面10，500，1 000 m高度层的O₃后向轨迹均呈散射状分布，距离地面10 m的O₃路径来源为河北西南部，距离地面500 m的O₃路径来源为河北南部，距离地面1 000 m的O₃主要途经地点为内蒙古西南部、西北部和河北东北部。     

激光雷达在湖北大气环境监测中的应用

介绍了激光雷达通过垂直扫描、水平扫描和车载走航等方法在湖北大气环境监测中的应用实例。利用地基激光雷达并结合星载激光雷达监测一次沙尘传输过程，沙尘传输高度为500~4 000 m之间，且出现3次尘降，地面PM₁₀出现3次峰值。利用激光雷达探测大气边界层高度，颗粒物浓度受边界层高度影响，当边界层高度降到500 m以下时，PM_2.5浓度达到120 μg/m³，边界层高度上升到1 500 m以上时，PM_2.5浓度降到30 μg/m³以下。利用激光雷达水平扫描技术，对襄阳市高新区污染物的影响进行溯源，监测得出颗粒物浓度上升的主要原因为地面扬尘。利用激光雷达车载走航监测技术，监测黄冈市颗粒物空间分布特征，在不同区域监测到2处污染扩散带，分别位于工业区与生活区。     

移动通信基站架设方式对地面电磁辐射分布的影响

选取南通市具有代表性的9种不同架设类型的基站现场实测,分析其地面水平方向上的电磁辐射分布特征,以掌握基站不同架设方式对地面电磁辐射的影响。结果表明:天线架设方式不同,地面电磁辐射强度及分布存在一定差异,落地塔监测值整体低于楼顶塔。50 m范围内,功率密度值由大到小依次是楼顶抱杆楼顶井字塔楼顶角钢塔楼顶景观塔楼顶集束天线楼顶拉线塔楼顶四角塔楼顶美化天线落地塔,地面最大值普遍出现在距离基站20 m~30 m范围。受天线架设高度、下倾角因素的影响,楼顶美化天线和楼顶角钢塔地面最大值点分别出现在距离基站60 m和70 m处,超出监测点位50 m布设范围。     

某石化工业园区大气中VOCs垂直分布的无人机监测研究

利用无人机对某石化工业园区地面至100 m大气中的VOCs进行监测，通过不同高度数据对比，总结该石化工业园区挥发性有机物的垂直分布特征，并分析其化学反应活性。监测结果表明，VOCs体积分数和总臭氧生成潜势随高度增加均呈下降趋势，地面和15~30 m高度的VOCs浓度及臭氧生成潜势基本一致。主要VOCs物种浓度垂直分布特征可分为均匀分布、随高度增加浓度不断降低、随高度增加浓度先升后降3种。含氧有机物和烷烃在大气中体积分数较大，主要特征挥发性有机物为丙酮、乙醛、乙烷、乙醇等；臭氧生成潜势贡献较大的组分为含氧有机物、烯烃和炔烃，关键活性物质为甲醛、乙醛、丁烯醛、正丁醛等。含氧有机物的体积分数和臭氧生成潜势贡献在地面至100 m高度都明显高于其他组分，应作为VOCs浓度和化学活性控制的重点。     

南京市声环境功能区划分的相关问题探讨

以城市总体规划为指导,对南京市声环境功能区划进行调整。根据相关技术规范,按照宜粗不宜细的原则,对城市和乡村功能区分别进行划分;明确了4类声功能区的距离范围,更加符合噪声传播特性;针对噪声污染特点,对于相关规范未涵盖的内容作了补充规定,使声环境管理更具针对性。区划结果表明,主城区1类区和3类区比例有所减小,2类区比例有所增加,全市范围内1类区比例仍为最高。     

大气中TSP,SO2浓度近地面垂直分布规律的研究

通过对ＴＳＰ、ＳＯ２浓度在不同高度实测研究．得出平顶山市ＳＯ２在１．５ｍ至２０ｍ不同高度监测，高度影响无显著性差异；ＴＳＰ在５ｍ至１５ｍ不同高度监测，高度影响无显著性差异。     

Alterations in the breeding habitats for two endangered raptor species along the Sava River basin, Croatia

Changes in habitat suitable for breeding of two sympatric raptor species (Haliaeetus albicilla and Aquila pomarina) were analysed along one of the most important breeding sites in Croatia for both species. The habitat suitability modelling was used to assess the influence of forestry practice during 2000-2006 using the known data on nesting places along research area. The four most important variables for lesser spotted eagle were elevation, distance from the nearest pasture, vertical distance to the nearest channel network and broadleaved forest placement (second axis from the principal component analysis of the enhanced vegetation index (EVI) index of MODIS images; November-March). The variables where white-tailed eagles showed greatest shift from overall habitat characteristics in the research area were broadleaved forest (second axis from the principal component analysis of the EVI index), height above the sea level, distance from the small settlements, vertical distance to channel network - all with negative loadings. The results clearly reveal the disproportion of suitable forests for raptors that were cut down in comparison to maturation of suitable forests.     

Vertical ozone variation in the lower troposphere of Delhi

Measurements of ozone in the urban environment of Delhi were carried out at ground level and heights of 23m, 51m, 117m and 153m at four different sites synoptically during 1989–90. A considerable ozone build up was observed all over Delhi and a significant vertical variation in its concentration was observed at all sites. At any given time O₃ levels were lowest at ground level and invariably increased with increasing distance from the ground.     

北京城市副中心海绵城市建设对地下水环境影响评价

以城市副中心北运河西岸湿地（甘棠大桥段）作为典型面状海绵体,利用2018年5月—9月采集的300组地表水和地下水监测数据,分析典型海绵体地下水水化学特征及形成机制,探讨不同含水层之间水力联系,并以Cl-为指示因子,结合其他水化学指标研究分析典型面状海绵体建设背景下地下水与地表水之间的交互作用及影响程度。结果显示,在垂向上,10 m、20 m含水层地下水之间联系密切,且受大气降水影响明显;在平面上,地表水对10 m、20 m含水层组地下水的影响距离为90 m～120 m,地表水对30 m含水层组地下水的影响距离为80 m～90 m。     

A Generalized Analytical Model for Crosswind-Integrated Concentrations with Ground-Level Deposition in the Atmospheric Boundary Layer

A generalized mathematical model describing the crosswind-integrated concentrations is presented for dispersion of pollutants emitted from a continuous source in the atmospheric boundary layer with deposition to the ground surface. The model is based on a solution of the resulting two-dimensional steady state advection-diffusion equation with deposition to the ground surface. It considers the horizontal wind speed as a generalized function of vertical height above the ground surface and eddy diffusivity as a function of both downwind distance from the source and vertical height. Various special cases of the model are deduced. A sensitivity analysis of the model prediction of the ground-level crosswind-integrated concentrations with deposition velocity is performed. Various issues and limitations associated with this work are discussed. The model is evaluated with the observations of a depositing tracer obtained from Hanford dual diffusion experiment in stable conditions. The statistical measures show that the present model, by considering deposition, is performing well with the observations. The model is giving an over-predicting trend with the observations and predicts 100 % cases within a factor of two. On the other hand, the consideration of a non-depositing condition for a depositing tracer yields the severe over-prediction and thus, it introduces the significant errors in the model prediction. The selection of the lower boundary condition for a depositing tracer at the height of deposition surface gives better prediction than those at a height of surface roughness length.     

Pattern Classification and Recognition of Invertebrate Functional Groups Using Self-Organizing Neural Networks

Self-organizing neural networks can be used to mimic non-linear systems. The main objective of this study is to make pattern classification and recognition on sampling information using two self-organizing neural network models. Invertebrate functional groups sampled in the irrigated rice field were classified and recognized using one-dimensional self-organizing map and self-organizing competitive learning neural networks. Comparisons between neural network models, distance (similarity) measures, and number of neurons were conducted. The results showed that self-organizing map and self-organizing competitive learning neural network models were effective in pattern classification and recognition of sampling information. Overall the performance of one-dimensional self-organizing map neural network was better than self-organizing competitive learning neural network. The number of neurons could determine the number of classes in the classification. Different neural network models with various distance (similarity) measures yielded similar classifications. Some differences, dependent upon the specific network structure, would be found. The pattern of an unrecognized functional group was recognized with the self-organizing neural network. A relative consistent classification indicated that the following invertebrate functional groups, terrestrial blood sucker; terrestrial flyer; tourist (nonpredatory species with no known functional role other than as prey in ecosystem); gall former; collector (gather, deposit feeder); predator and parasitoid; leaf miner; idiobiont (acarine ectoparasitoid), were classified into the same group, and the following invertebrate functional groups, external plant feeder; terrestrial crawler, walker, jumper or hunter; neustonic (water surface) swimmer (semi-aquatic), were classified into another group. It was concluded that reliable conclusions could be drawn from comparisons of different neural network models that use different distance (similarity) measures. Results with the larger consistency will be more reliable.     

北京市中心商区射频电磁环境测试与分析

各类无线技术的发展和应用导致公众曝露于环境中的电磁场辐射的程度越来越高,由此引发的对人体健康风险的担忧促使诸多国家和组织开展了相关研究,并制定了电磁环境控制限值,电磁环境的空间分布也成为至关重要的基础数据。于2019年10—12月对北京市中心3个典型商区的电磁环境进行了测试,测试频段为10 MHz～8 GHz,属于射频范围。通过空间插值方法对测试数据进行处理,从而得到测试区域的射频电磁环境空间分布地图。对测试数据的进一步分析表明,测试区域的射频电磁环境水平主要分布在0.5～2.5 V/m,随空间距离变化较为剧烈,总体上符合《电磁环境控制限值》(GB 8702—2014)的要求。建议在城市发展过程中,对射频电磁环境进行持续、精细的监测。     

Vertical concentration gradients of volatile organic compounds in two NS-oriented street canyons

Diffusive samplers were used to measure the vertical concentrations of benzene, toluene, n-hexane, cyclohexane, ethylbenzene and o-, m- and p-xylenes on both sides of two NS-oriented street canyons in Murcia (Spain) during a 5-day period. Non-dimensional relationships of concentration and height were calculated in order to study the behaviour of their concentration vertical profiles. The results show that the vertical profiles of benzene, toluene, n-hexane and cyclohexane concentrations were similar in both streets and on both sides of each street. Some differences were found in vertical profiles between streets and sides for ethylbenzene and xylenes, probably due to their higher affinity for adsorption into building materials. The similarities found for the first set of VOCs suggest that the dynamics of the dispersion was the same for both streets and was mainly influenced by microscale thermal effects. Finally, the concentration measurements of benzene, toluene, n-hexane, cyclohexane, and ethylbenzene were adjusted to expressions in the form c?=?c ₀(h/h ₀) ^A , and a regression coefficient R ²?=?0.962 (p?=?0.0000) was obtained. The decreasing concentration of these compounds with height should be taken into account when assessing population exposure to these pollutants.