上海市城郊臭氧浓度变化分析及模拟预报

利用上海市普陀、南汇、淀山湖3个臭氧观测站2005年的臭氧小时观测资料,首先对市区和郊区的大气臭氧浓度的污染特征和变化情况进行了分析,结果表明,上海市郊区的臭氧浓度和污染水平高于市区,且臭氧浓度日变化在市区呈现明显的双峰现象,而郊区则是单峰型变化规律。然后运用基于统计学理论的最小二乘支持向量机（LSSVM）方法对3个站的日（24h）平均和白日（12h）平均以及日最大值臭氧浓度进行预测,得到较好的预报效果。     

我国城市污水处理

我国城市污水处理的现状以及当前全国城市污水厂普遍应用的污水处理工艺,在选择城市污水处理工艺时应考虑资金及土地资源方面的问题,通过开发新型高效污水处理工艺提高污水净化率和污水处理量。同时通过建立和完善城市污水处理制度,提高城市居民环保意识,污水处理走向市场化,实现社会与政府的共赢。     

城镇环境规划

文章主要探讨了编制小城镇环境规划的理论基础、指标体系、主要内容、城镇环境专题规划及其技术方法,重点对空气污染防治规划、水环境专题规划、噪声污染控制规划和城镇固体废物处理及处置专题规划作了具体分析,论证了正确处理城镇发展与环境保护之间的关系。改善城镇环境质量,促进城镇生态系统的良性循环,实现城镇的可持续发展,已成为各国政府环境保护工作的重点。     

中国城市空气质量分级管理策略探讨

本文在充分剖析我国现阶段城市环境空气质量及相关管理工作存在的主要问题的基础上,探讨了以改善城市空气质量兼顾城市群效应控制为重点的城市空气质量分级管理策略。研究提出,为适应新的污染特征和形势,国家应针对不同地区、不同污染来源特征、不同污染程度的各类城市实行分类指导和分级管理的思路。     

Characterization of atmospheric aerosol (PM10 and PM2.5) from a medium sized city in São Paulo state, Brazil

Air pollution causes deleterious effects on human health with aerosols being among the most polluting agents.The objective of this work is the characterization of the PM_(2.5) and PM_(10) aerosol mass in the atmosphere.The methods of analysis include WD-XRF and EDS.Data were correlated with meteorological information and air mass trajectories(model HYSPLIT)by multivariate analysis.A morphological structural analysis was also carried out to identify the probable sources of atmospheric aerosols in the city of Sao Jose do Rio Preto,Brazil.The mean mass concentration values obtained were 24.54 μg/m~3 for PM_(10),above the WHO annual standard value of 20 μg/m~3 and 10.88 μg/m~3 for PM_(2.5) whose WHO recommended limit is10 μg/m~3.WD-XRF analysis of the samples revealed Si and Al as major components of the coarse fraction.In the fine fraction,the major elements were Al and S.The SEM-FEG characterization allowed identifying the morphology of the particles in agglomerates,ellipsoids and filaments in the PM_(10),besides spherical in the PM_(2.5).The analysis by EDS corroborated WD-XRF results,identifying the crustal elements,aluminosilicates and elements of anthropogenic origin in the coarse fraction.For the fine fraction crustal elements were also identified;aluminosilicates,black carbon and spherical particles(C and O) originating from combustion processes were predominant.The use of multivariate analysis to correlate air mass trajectories with the results of the morpho-structural characterization of the particulate matter allowed confirmation of the complex composition of the particles resulting from the combination of both local and long-distance sources.     

The method for leakage detection of urban natural gas pipeline based on the improved ITA and ALO

To solve the problems of the difficulty in early leakage monitoring and larger positioning error for urban hazardous chemicals pipelines, the optimized method based on the improved Inverse Transient Analysis (ITA) and Ant Lion Optimizer (ALO) was proposed. Firstly, based on the obtained experiment's results of leakage of natural gas in the non-metallic pipeline, the segment classification method was incorporated into the pressure gradient calculation. The modified method can adapt to the multi-node characteristics of urban pipe networks and help to obtain the preliminary positioning calculation results after optimization. Then the calculation results were embedded in the ITA calculation model. The input parameters of the gas pipeline such as boundary conditions, leakage rate and friction coefficient were used to establish the characteristic linear equations. Then the objective function of the least-squares criterion was defined, and the improved ITA model suitable for leakage detection of urban natural gas pipeline networks was constructed. Finally, the ALO was used to optimize the calculation process of the improved ITA model, and iteratively optimize the optimal friction coefficient and its corresponding minimum objective function (OF) value. As a result, a more precise location of the leakage source was calculated. The validation of the modified method is conducted by comparing the calculated values with the experiment's results. The results show that the method can accurately predict the location where the pipeline leakage occurs. The minimum error is 3.17%. Compared with the traditional ITA, this method not only accelerates the convergence speed of the objective function, but also improves the accuracy of location calculation.     

基于神经网络的城市夜间环境监控与预测

因夜间天空亮度分布具有非线性变化特点,故引入神经网络算法,建立基于时间序列的夜天空亮度预测模型,夜天空亮度预测模型可为城市光污染防治提供评价依据.文章对神经网络的原理进行了论述,建立了基于时间序列预测模型.以测试数据为训练样本集,基于MATLAB(矩阵实验室,Matrix Laboratory的简称),采用改进的BP算法(误差反向传播算法)对网络进行学习训练,并对存在的误差进行了分析.基于时间序列BP神经网络的夜天空预测模型,当隐含层神经元数目为5,训练函数为L-M优化算法(trainlm)时,最大绝对误差可达到0.003 6 cd/m2,最大相对误差达到2.361 4%.结果表明,模型的运行结果与试验数据比较吻合,输出与目标矢量之间相关性也较好.     

基于生态安全的快速城市化地区空间冲突测度 ——以长株潭城市群为例

空间冲突是城市化过程中各种矛盾形成与激化的直接原因,是影响区域可持续发展的关键因素,合理测度快速城市化地区的空间冲突水平,对于优化区域发展模式、 避免区域生态风险具有重要意义。在利用遥感与GIS技术分析长株潭近年来空间格局变化的基础上,量化影响区域生态安全的空间外部压力值、 生态风险暴露值、 生态风险效应值3个因子,构建基于生态安全的空间冲突测度模型,对长株潭地区的空间冲突水平进行评估。研究表明:近年来长株潭地区的空间冲突作用强度总体呈现上升趋势,1993—2008年其冲突指数均值由0.264增长到0.323,且严重失控级别空间冲突的区域面积比例增幅最大,达1.07倍;不同空间类型的空间冲突强度不同,林地、 耕地的空间冲突水平相对较低,建设用地的空间冲突水平较高;城乡过渡地带是空间格局变化最为频繁、 空间冲突最为激烈的区域,其次是城市内部,农村地区的空间冲突强度远远低于城市。     

城市轨道交通浮置式减振措施的减振降噪效果

从分析轨道交通地下隧道振动传播特征出发,说明了地下振动的传播规律,并给出了不同埋深条件下地下振动影响范围的经验公式;结合地下振动激发频率特征的分析,对减振措施的减振效果的合理评价量进行了分析,指出采用Z计权减振效果评价量将获得与实际应用效果一致的降噪效果。结合两种浮置式减振措施减振降噪效果的实测,指出浮置板道床的减振效果应采用安装减振垫浮置板道床前后桥面的Z振级差来评价,而不宜采用轨面与桥梁直接的振级落差来评价。对橡胶减振垫以及钢弹簧浮置板的实测减振降噪效果进行了介绍。     

Advancing urban ecosystem governance in New York City: Shifting towards a unified perspective for conservation management

New York City’s extensive municipal park system is home to forests, wetlands, and grasslands that provide important ecological and social benefits to the city’s population. While efforts and programs exist to restore and protect these spaces, management recommendations are complex due to variable conditions in urban natural areas. To advance the management of urban natural areas, the first comprehensive ecological assessment was conducted through a collaborative effort across 4000 ha of natural areas within New York City parkland. Field and spatial data were collected and analyzed to identify the extent of forests, the types of forests, and their conditions. This approach will help guide decision-making and prioritization of natural area management at the regional level by developing unique quantitative targets for urban forests. This project serves as an example of collaboration between private and public institutions advancing the governance of urban natural areas to achieve citywide conservation and policy goals.