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近年来,随着城市经济的不断增长,人民生活水平的不断提高,城市交通发展迅速,机动车辆大幅度增加,城市交通噪声污染问题越来越突出。城市建设发展迅速,新建扩建的街道、马路使原来偏僻区域变成了繁华嘈杂的市区,从而加重了交通噪声对周边环境的影响。交通噪声声源流动、声级高、干扰时间长、影响范围广,严重扰乱了城市居民的生活、工作和休息。 相似文献
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噪声不仅干扰人们的正常生活,严重时可以危害人的身心健康.随着交通事业的快速发展,一大批高速公路迅速建成,交通噪声污染不容忽视.对西宝高速公路沿线交通噪声进行了实地昼夜监测,结果表明交通噪声夜间超标较为严重,干扰了沿线居民的正常生活.分析了污染现状和原因,并提出了降低道路交通噪声的一些简单措施. 相似文献
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1997年,张家港市在市区建成区内全面建成噪声达标区,并通过了苏州市的验收。现就张家港市噪声达标区的创建谈谈环境噪声的管理。1值得借鉴的经验11加大执法管理力度在创建噪声达标区的过程中,对市区固定声源的管理加大了执法力度,对违反噪声法的行为坚决依法... 相似文献
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通过对杭州市典型高架复合道路交通噪声监测,研究高架复合道路交通噪声的时空分布规律。结果表明,噪声与车流量、车辆类型及车速密切相关;噪声随着与高架路距离的增大,地面各测点的噪声值呈递减趋势;高架复合道路平直段与下坡路段的噪声在临街建筑竖直立面的分布规律基本一致,但在不同高度的影响程度上存在一定差异。 相似文献
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社会生活噪声污染来源多、成因复杂、影响范围广,对公众健康危害大。产生社会生活噪声污染纠纷时,其法律主体复杂,涉及部门多,受影响群众覆盖范围广,是社会各界较为关注的噪声类型之一。邻里噪声是社会生活噪声的重要组成部分。介绍了法国、德国、美国等国家邻里噪声的立法现状,我国国家层面有关邻里噪声的法律规定,以及地方邻里噪声的立法实践;系统分析了江苏省邻里噪声扰民的主要类型、特点和污染防治的现状;针对性地提出了邻里噪声污染防治的立法建议,可为江苏省噪声污染防治立法提供参考。 相似文献
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This paper is concerned with a preliminary experimental investigation of the interaction between large turbulent structures, generated in the wake of a circular cylinder, and the rough-wall turbulent boundary layer separated flow immediately downstream of a simple street canyon type geometry represented by backward-facing step. The motivation for the work was to provide some initial data for the validation of a 3-D k- turbulence model used for the prediction of flows and pollutant dispersion within the urban canopy. The aim has been to assess the extent of the perturbation of a simulated street canyon caused by regular large-scale eddies generated upstream. The research has involved the use of thermal anemometry to determine mean velocity and turbulence characteristics both upstream and downstream of the step, together with the mean reacttachment length for the recirculating flow. The results indicate that the presence of the cylinder in the flow reduces the reattachment length. In addition, the periodic structures generated in the cylinder wake are rapidly mixed with the turbulence in the step shear layer such that no periodicity is detected at the reattachment zone. 相似文献
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A technique is presented to solve analytically the turbulent diffusion equation for the concentration of a passive contaminant
emitted from an elevated continuous source into the atmosphere. A generalized method of solution using Sturm–Liouville and
WKB theories is developed to overcome difficulties due to the height‐dependent wind velocity and diffusion coefficient appearing
in the diffusion equation. The method presented in this paper is able to derive an asymptotic expression for the concentration
obtained from the solution of the atmospheric diffusion equation which involves explicitly inhomogeneous wind velocity and
diffusion coefficient. The diffusion equation model derived from this method can be applied in a practical prediction of contaminant
concentration in a turbulent atmosphere.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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A 2D analytical turbulent diffusion model for particle dispersion and deposition at different heights along the pipe flow
and circumferential deposition has been developed. This liquid–solid turbulent diffusion model presented in this paper has
emanated from an existing gas–liquid turbulent diffusion model. This model can be used as a handy tool for quick estimation
one and two-dimensional deposition fluxes of particles in water distribution networks. A comprehensive 3D numerical investigation
has been carried out using multiphase mixture model available in “Fluent 6.2” to verify the above analytical model. Different
particles sizes and densities were used for 3D numerical investigations. The deposition was studied as a function of particle
diameter, density, and fluid velocity. The deposition of particles, along the periphery of the pipe wall and at different
depths, was investigated. Both the models findings matched with qualitative phenomena such as deposition of heavier particles
at the bottom of the pipe wall were higher at lower velocities and lower at higher velocities. The lighter particles were
found mostly suspended with homogeneous distribution. Smaller particles were also suspended with marginal higher concentration
near the bottom of the pipe wall. This marginal higher concentration of the smaller particles was found to be slightly pronounced
for lower velocity. These analogies of particles are well discussed with the ratio between free-flight velocity and the gravitational
settling velocity. Extended analytical model results were compared with the 3D computational fluid dynamics simulation results.
Discrepancies in the model results were discussed. 相似文献
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This paper presents a mathematical model of local pollutant dispersion designed to compute the concentration field above and
around the Marcoule nuclear site. The model is based on integrating the classical turbulent diffusion equation, corrected
(prior to integration) by experimental wind tunnel data obtained for a scaled-down model of the site. The computed results
are compared with full-scale experimental observations at Marcoule in the case of neutral atmosphere. A comparison with the
standard Gaussian model is also made. Finally, a critical analysis of the model is presented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Mohamed F. Yassin 《Environmental monitoring and assessment》2012,184(6):3749-3760
This paper presents a model for coupling the statistics of wind velocity distribution and atmospheric pollutant dispersion.
The effect of wind velocity distribution is modeled as a three-dimensional finite-impulse response (3D-FIR) filter. A phase
space representation of the 3D-FIR filter window is discussed. The resulting pollutant dispersion is the multiplication in
the phase space of the 3-D Fourier transform of the pollutant concentration and the volume described by the filter window
coefficients. The shape of the filter window in the phase space enables representing such effects as vortex shedding thermal
currents, etc. The impact of spatial distribution of the sensors on the resulting pollutant spatial distribution and the 3-D
FIR filter model employed also discuss. The case of a neutrally buoyant plume emitted from an elevated point source in a turbulent
boundary layer considers. The results show that wind turbulence is an important factor in the pollutant dispersion and introduces
expected random fluctuations in pollutant distribution and leads to spreading the distribution due to wind mixing. 相似文献
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Isao Kanda Yukio Yamao Toshimasa Ohara Kiyoshi Uehara 《Environmental Modeling and Assessment》2013,18(2):221-248
This paper proposes an atmospheric diffusion model for traffic-related emission in urban areas within a few hundred meters from relevant roads. The model adopts the mass-conservation (MC) principle for the velocity calculation and the advection-diffusion (AD) equation for the concentration calculation. This MC+AD combination was chosen to achieve fast calculation for complex geometries. To compensate for the inherent deficiencies of MC and AD, as many known properties possible of turbulent boundary-layer flow over obstacles are incorporated into the MC calculation, and the diffusivity in AD is derived from the velocity spectrum as a function of distance from the emission source. The model is evaluated against wind-tunnel experiments ranging from point-source emission in uniform urban canopy to along-road emission in real city geometries. The model performs well in relatively simple configurations, but the performance deteriorates considerably as the complexity increases. However, in real city geometries, the model exhibits distinctly better performance in terms of statistical indices than a conventional Gaussian-plume model that neglects the effect of individual buildings. The model is therefore a viable option for environmental assessment. 相似文献
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Cees J. M. Kramer 《Environmental monitoring and assessment》1986,7(2):169-187
The high variabilility in coastal water parameters allows no effective large scale monitoring exercise within acceptable logistic and economic means; however, in the ideal case monitoring of marine pollution should comprise biotic and abiotic compartments. Different regions, e.g. turbulent, polluted, turbid coastal areas, relative clear clean open sea and relatively undisturbed sediments require their specific approach, for which strategies are presented.Based on surveys from the Dutch Wadden Sea and North Sea, the dissolved and particulate water fractions and sediment are discussed in terms of possible objects for monitoring. 相似文献
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用数理统计的原理,当样本容量满足检验方法要求时,用柯尔莫哥洛夫--斯米尔诺夫、皮尔逊、概率纸等法对绵阳市城区SO2监测值进行分布类型的统计检验。其结果SO2的时空分布类型为近似对数正态。用几何均数代表样本的平均值,例行监测时段的SO2测值与增加采样频率后的测值基本无差异。而用算术均数表示平均值时,均值则落在总体均值的置信区间外。故当样本分布类型确定后,样本的主要特征数应由分布类型确定。 相似文献