Carbonyl sulfide and dimethyl sulfide fluxes in an urban lawn and adjacent bare soil in Guangzhou, China

Carbonyl sulfide (COS) and dimethyl sulfide (DMS) fluxes from an urban Cynodon dactylon lawn and adjacent bare soil were measured during April–July 2005 in Guangzhou, China. Both the lawn and bare soil acted as sinks for COS and sources for DMS. The mean fluxes of COS and DMS in the lawn (–19.27 and 18.16 pmol/(m2 sec), respectively) were significantly higher than those in the bare soil (–9.89 and 9.35 pmol/(m2 sec), respectively). Fluxes of COS and DMS in mowed lawn were also higher than those in bare soils. Both COS and DMS fluxes showed diurnal variation with detectable but much lower values in the nighttime than in the daytime. COS fluxes were related significantly to temperature and the optimal temperature for COS uptake was 29°C. While positive linear correlations were found between DMS fluxes and temperature. COS fluxes increased linearly with ambient COS mixing ratios, and had a compensation point of 336 ppt.     

福州城市边缘区森林土壤重金属污染特征及评价

为掌握福州城市边缘区森林土壤重金属污染特征,选取10个典型区域作为研究对象,分析森林土壤中Zn、Mn、Cr、Pb、Cu 5种重金属的含量及分布特征,并采用单项污染指数和综合污染指数法对土壤进行质量评价,结果表明:Cr、Pb是该区土壤重金属污染最主要的元素;Zn、Cu、Pb、Cr含量随土层深度增加而减少,Mn则相反;Zn...     

动力与热力抬升对烟气抬升高度的影响分析

通过模式选择和计算,得出烟气抬升高度的增加与动能和热能的关系,表明当烟囱出口处风速分别为3 m/s、2 m/s和1 m/s时欲增加同样大小的烟气抬升高度,需要的动能比热能要高,结论认为烟气的热力提升比动力提升的贡献大。     

抚仙湖流域城镇污染分析及控制策略

对抚仙湖流域城镇生活污染、城镇径流污染及污水处理设施等进行了全面调查与分析,并提出了相应的污染控制策略。     

县级城市人居环境主客观指标体系与评价模型对比研究

本文对人居环境相关研究进行了阐述,并就城市人居环境指标体系与评价模型进行了分析研究。提出了人居环境质量主客观评价结合模型,其中指标体系包括四个一级指标和18个单项指标,并依据我国黄河三角洲高效经济区内14个县级城市2007年的调查统计资料,对人居环境客观建设水平和居民满意度进行了对比评价。运用因子分析法处理指标数据,问卷调查的方法进行满意度评价。评价结果科学可行,并揭示出影响县级城市人居环境的根本因素。     

城市环境保护中污水治理的相关问题研究

随着我国向工业型国家转型的进程加快,我国作为一个水资源贫乏的国家,水污染的问题日益突出。因此,对于我国城市污水处理问题进行研究探讨,对于实现我国可持续发展战略有着重大的意义。本文主要对目前我国城市污水处理中存在的问题进行了分析研究,并在此基础上,对我国的城市污水处理提出了一些有针对性地对策与措施。     

重庆市主城区PM2.5时空分布特征

利用2014年6月1日至2015年5月31日重庆市主城区17个国控空气质量监测站24 h自动连续采样的PM_(2.5)浓度数据,探讨了重庆市主城区PM_(2.5)时空分布特征.结果表明:1重庆市主城区PM_(2.5)季节浓度由高到低依次为冬季(100.2μg·m~(-3))、秋季(66.1μg·m~(-3))、春季(45.9μg·m~(-3))和夏季(33.4μg·m~(-3))(P0.05).2重庆市主城区PM_(2.5)月均浓度变化呈单峰单谷型,1月PM_(2.5)月均浓度最高(P0.05),达到120.8μg·m-3.3逐日变化,国控17个空气质量监测站PM_(2.5)日均浓度曲线都呈现出尖峰和深谷交替变化的锯齿状.4重庆市主城区16个国控监测点(除缙云山对照点)PM_(2.5)浓度日变化在全年、春季、秋季和冬季都呈现明显的双峰双谷型.5PM_(2.5)与SO_2、NO_2和CO都呈显著正相关(P0.01),表明SO_2、NO_2和CO的二次转化对PM_(2.5)浓度具有显著影响.     

基于快速聚类方法分析常州市区PM2.5的统计特性

运用统计方法研究常州市区2013~2014年6个国控点六项基本污染物(SO_2、NO_2、CO、O_3、PM_(2.5)和PM_(10))月平均浓度变化,结果表明,除O_3外,其它五项污染物月平均浓度夏季较低冬季较高.颗粒物与风速之间的关系为PM_(2.5)浓度随风速的升高一直降低,PM_(10)随风速的升高浓度先降低后升高.采用快速聚类分析(k-means)并运用SWV和DIV指数对六项基本污染物进行分类,得到4个样本分类.与依据颗粒物化学成分或粒径谱对PM进行源解析方法不同,本研究更多是从PM_(2.5)与其它污染物相关关系以及污染程度等角度按照欧式距离进行分类.不同类中PM_(2.5)来源明显不同,类1中PM_(2.5)与化石燃料燃烧排放密切相关,类2与O_3密切相关,类3与城市不完全燃烧排放、区域灰霾污染密切相关,类4可以归类于城市"背景"类.快速聚类分析结果也表明常州市区PM_(2.5)有着复杂的来源.     

城市交通大气污染物与温室气体协同控制效应评价

针对乌鲁木齐城市交通领域12项减排措施开展协同控制效应评估,构建空气污染物与温室气体协同减排当量(APeq)指标进行减排效果归一化,识别措施是否具有协同减排效果,并进一步计算单位APeq减排成本,从成本有效性角度对各项减排措施进行排序.研究结果表明,出租车、私家车油改气以及纯电动轿车替代汽油轿车3项措施不具有协同控制效应;而提高尾气排放标准、天然气公交替代柴油公交、提升小客车燃油经济性、油品升级、淘汰黄标车、发展轨道交通、引入快速公交等措施可以实现局地大气污染物与温室气体的协同减排.费用-效果分析表明,提高小客车燃油经济性的单位APeq减排成本最低,具有良好的成本有效性;而发展轨道交通虽然单位APeq减排成本较高,但总体减排效果较好.     

Evaluation of accuracy of linear regression models in predicting urban stormwater discharge characteristics

Stormwater runoff has been identified as a source of pollution for the environment, especially for receiving waters. In order to quantify and manage the impacts of stormwater runoff on the environment, predictive models and mathematical models have been developed. Predictive tools such as regression models have been widely used to predict stormwater discharge characteristics. Storm event characteristics, such as antecedent dry days （ADD）, have been related to response variables, such as pollutant loads and concentrations. However it has been a controversial issue among many studies to consider ADD as an important variable in predicting stormwater discharge characteristics. In this study, we examined the accuracy of general linear regression models in predicting discharge characteristics of roadway runoff. A total of 17 storm events were monitored in two highway segments, located in Gwangju, Korea. Data from the monitoring were used to calibrate United States Environmental Protection Agency＇s Storm Water Management Model （SWMM）. The calibrated SWMM was simulated for 55 storm events, and the results of total suspended solid （TSS） discharge loads and event mean concentrations （EMC） were extracted. From these data, linear regression models were developed. R2 and p-values of the regression of ADD for both TSS loads and EMCs were investigated. Results showed that pollutant loads were better predicted than pollutant EMC in the multiple regression models. Regression may not provide the true effect of site-specific characteristics, due to uncertainty in the data.