中国生态环境问题及环境保护计划

本将中国面临的生态环境问题归纳为七大问题,即：土地流失、土地荒漠化、森林覆盖面积减少、草原退化、自然灾害加剧、空气污染和酸雨、水污染和缺水。以统计数据为依据,从7个方面展现了生态环境的现状和遭受破坏的程度。扼要说明了由灾害和污染所造成的经济损失。介绍了中国政府就治理污染、防止生态环境破坏的环境保护计划。     

电催化氧化中的三种催化材料处理酸性红B染料的比较研究

本文采用三种不同催化机理的材料———半导体材料TiO2 、软锰矿石和混合稀土进行了电催化氧化 (ECO)染料酸性红B的研究 ,结果表明 ,稀土材料在ECO体系中呈负催化效应 ;软锰矿石的色度去除催化效果明显 ;TiO2 的催化效果最显著 ,其色度和COD去除效果可比无催化剂时效果分别提高60 %和 75% ,可以作为电催化氧化的催化剂。并进一步研究了TiO2 用量对电催化氧化 (ECO)的影响。     

Improving the accuracy of emission inventories with a machine-learning approach and investigating transferability across cities

ABSTRACT

This study presents a novel method for integrating the output of a microscopic emission modeling approach with a regional traffic assignment model in order to achieve an accurate greenhouse gas (GHG, in CO_2-eq) emission estimate for transportation in large metropolitan regions. The CLustEr-based Validated Emission Recalculation (CLEVER) method makes use of instantaneous speed data and link-based traffic characteristics in order to refine on-road GHG inventories. The CLEVER approach first clusters road links based on aggregate traffic characteristics, then assigns representative emission factors (EFs), calibrated using the output of microscopic emission modeling. In this paper, cluster parameters including number and feature vector were calibrated with different sets of roads within the Greater Toronto Area (GTA), while assessing the spatial transferability of the algorithm. Using calibrated cluster sets, morning peak GHG emissions in the GTA were estimated to be 2,692 tons, which is lower than the estimate generated by a traditional, average speed approach (3,254 tons). Link-level comparison between CLEVER and the average speed approach demonstrates that GHG emissions for uncongested links were overestimated by the average speed model. In contrast, at intersections and ramps with more congested links and interrupted traffic flow, the average speed model underestimated GHG emissions. This proposed approach is able to capture variations in traffic conditions compared to the traditional average speed approach, without the need to conduct traffic simulation.

Implications: A reliable traffic emissions estimate is necessary to evaluate transportation policies. Currently, accuracy and transferability are major limitations in modeling regional emissions. This paper develops a hybrid modeling approach (CLEVER) to bridge between computational efficiency and estimation accuracy. Using a k-means clustering algorithm with street-level traffic data, CLEVER generates representative emission factors for each cluster. The approach was validated against the baseline (output of a microscopic emission model), demonstrating transferability across different cities .     

Copper-promoted heterogeneous Fenton-like oxidation of Rhodamine B over Fe3O4 magnetic nanocatalysts at mild conditions

Environmental Science and Pollution Research - Rhodamine B (RhB) is used in various industries and its effluent must be effectively treated because of its harmful and carcinogenic nature. In this...     

Assessing the Eutrophication of Shengzhong Reservoir Based on Grey Clustering Method

Abstract

Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water environment to establish a relatively complete model suitable for the reservoir eutrophication evaluation and appropriately evaluate the quality of reservoir water, providing evidence for reservoir management. According to China’s lakes and reservoir eutrophication criteria and the characteristics of China’s eutrophication, as well as certain evaluation indices, the degree of eutrophication is classified into six categories with the utilization of grey classified whitening weight function to represent the boundaries of classification, to determine the clustering weight and clustering coefficient of each index in grey classifications, and the classification of each clustering object. The comprehensive evaluation of reservoir eutrophication is established on such a foundation, with Sichuan Shengzhong Reservoir as the survey object and the analysis of the data attained by several typical monitoring points there in 2006. It is found that eutrophication of Tiebian Power Generation Station, Guoyuanchang and Dashiqiao Bridge is the heaviest, Tielusi and Qinggangya the second, and Lijiaba the least. The eutrophication of this reservoir is closely relevant to the irrational exploitation in its surrounding areas, especially to the aggravation of the non-point source pollution and the increase of net-culture fishing. Therefore, it is feasible to use grey clustering in environment quality evaluation, and the point lies in the correct division of grey whitening function     

江汉平原小麦开花前降水分布特点及同期渍害的产量效应

江汉平原小麦生长期易受渍害导致减产。在系统分析1983~2012年江汉平原腹地荆州市小麦生育期降水分布特点的基础上,于2011~2012年度及2012~2013年度,以郑麦9023为试验材料,通过田间试验与盆栽试验相结合的方法,分别在拔节期及孕穗期进行渍水处理,探讨其对株高、旗叶光合速率、叶片黄化进程的影响及其与干物质积累量和籽粒产量的关系。结果表明：江汉平原1983~2013年小麦拔节期至孕穗期1/3以上年份同期降水量在802 mm以上,极限降雨量达1944 mm,即较多年份有渍害风险;进一步研究表明拔节期渍水和孕穗期渍水均导致旗叶光合速率降低,叶片黄化进程加快,其中孕穗期渍水对以上指标的影响大于拔节期;拔节期渍水和孕穗期渍水均导致株高降低、干物质积累量降低,最终籽粒产量显著降低,其中拔节期渍水处理成熟期籽粒产量比对照降低163%,孕穗期渍水处理籽粒产量比对照降低218%。在本试验条件下,拔节期渍水处理和孕穗期渍水处理均导致小麦植株各种光合指标降低,最终干物质积累量和籽粒产量均显著降低,且孕穗期渍水处理对产量等的影响大于拔节期渍水处理     

Study on the influence of material thermal characteristics on dust explosion parameters of three long-chain monobasic alcohols

Sensitivity and severity parameters are critical for risk assessment and safety management of dust explosions. In this paper, to reveal the effects of material thermal characteristics on dust explosions parameters during monobasic alcohols dust explosions, three long chain monobasic alcohols, being solid at room temperature and similar in physical–chemical properties, were chosen to carry out experiments in different functional test apparatus according to the internationally accepted ASTM standards. As a result, it was found that the material thermal characteristics strongly affected these basic explosive parameters. On the one hand, for the sensitivity parameters, Minimum Ignition Temperature, Minimum Ignition Energy and Electrical Resistivity were the highest in the Eicosanol dust cloud, while Minimum Explosible Concentration in this cloud was the lowest. On the other hand, for severity parameters, Maximum Explosion Pressure in Eicosanol dust cloud always maintained the highest values as varying the dust concentrations. In contrast, Deflagration Index showed a complex trend.     

基于神经网络和数值模型的重点区域PM2.5预报比较分析

应用BP神经网络法建立京津冀及周边城市、汾渭平原、苏皖鲁豫交界地区和长三角地区等重点区域95个城市PM_2.5预报模型,对2020年秋冬季上述地区城市开展未来7 d的PM_2.5预测预报,并对比同期业务化运行的数值模型预报结果和各城市人工订正后预报结果,对3方法预报效果进行分析评估.结果表明:（1） 4区域神经网络法模型性能短期预报相对较好,中长期有所降低,对4区域均有一定的系统性高估,苏皖鲁豫交界地区系统性偏差最小,长三角地区偏差最显著.数值模型区域预报水平较神经网络有所降低,各评价指标总体低于神经网络,对辖区城市间预报效果较神经网络差异更大.（2）神经网络、数值模型和人工订正方法对4区域PM_2.5浓度预报准确率普遍较低,平均不足50%,准确水平总体呈:神经网络>人工订正>数值模型. 3方法分指数级别范围准确率均大幅提升,4区域1～4 d平均准确率均在65%以上,神经网络模型和人工订正水平相近,总体高于数值模型.（3）在预报中度及以上污染级别日时,数值模型在京津冀及周边城市、苏皖鲁豫交界地区和长三角地区效果均较...     

华中地区夏季PM2.5中水溶性离子污染特征及来源分析

为探究我国华中地区不同区域夏季大气PM_2.5中水溶性离子污染特征及来源,选取武汉、随州和平顶山分别作为城市、郊区和农村监测站点进行大气PM_2.5样品采集,分析了大气中PM_2.5质量浓度以及8种水溶性无机离子含量.结果表明,采样期间3个站点ρ（水溶性离子）呈明显的空间分布特征,即:平顶山[（36.29±9.82）μg·m^-3]>武汉[（32.55±10.05）μg·m^-3]>随州[（26.10±6.23）μg·m^-3],分别占PM_2.5的质量分数为52.47%、 51.32%和48.61%,平顶山站点由于农村生物质燃烧活动,水溶性离子占比最大,其中,二次离子（SNA）是主要的离子成分,分别占总水溶性离子的95.65%、 96.12%和97.33%.武汉（0.64）和随州（0.63）站点硫氧化率均值高于平顶山站点（0.50）,而武汉（0.18）和平顶山（0.19）站点氮氧化率高于随州站点（0.15）,站点间硫氧化率和氮氧化率差...