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551.
利用河南省环境空气质量新标准实施一期城市(郑州、开封)2013年的环境空气自动监测数据,分析了实施《环境空气质量标准》(GB 3095—2012)对这2个城市空气质量评价的影响。研究发现,若采用新标准,郑州、开封污染物年均浓度超标情况加重;城市空气质量达标率从51%、71%下降到35%和31%,下降了16和40个百分点;PM2.5的纳入是空气质量达标率下降的最主要原因,大于NO2标准的收严和CO、O3纳入评价指标的影响,其超标率分别为58%(郑州)和63%(开封);且PM2.5取代PM10成为郑州、开封的首要污染物,其作为首要污染物的比例均大于70%。  相似文献   
552.
淮河支流污染物综合降解系数动态测算   总被引:10,自引:1,他引:9  
确定河流污染物综合降解系数动态变化规律对提高水环境容量测算精度和水环境管理具有重要意义。通过现场模拟法,采用一维稳态模型测算了淮河支流洪河五沟营-塔桥乡河段COD、氨氮和总磷在枯水期、平水期和丰水期的综合降解系数,COD、氨氮和总磷降解系数在各水期的关系为枯水期平水期丰水期,提出了建议值并利用实测浓度对计算结果进行了检验,结果表明,不同水期综合降解系数吻合情况较好。  相似文献   
553.
针对《环境空气质量指数(AQI)技术规定(试行)》(HJ 633-2012)中对空气质量AQI实时发布存在的欠缺,从增加颗粒物1 h浓度的AQI分级浓度限值及颗粒物24 h滑动平均值计算方法改进着手,解决PM2.5和PM10的24 h滑动平均值实时延迟、1 h平均值代替24 h滑动平均值偏高等问题。  相似文献   
554.
Ecosystems and their components provide a lot of benefits for the welfare of human beings. Coupled with increasing socioeconomic development, most of the rapidly developing and transitional countries and regions have been experiencing dramatic land use changes. This has resulted in a large amount of forestland, grassland, and wetland being occupied as residential and industrial land or reclaimed for arable land, which in turn results in a sharp deterioration of ecosystem services around the world. Shandong Province, an economically powerful province of China, was chosen as a case study in order to capture the impact of socioeconomic development on ecosystem services. By way of the study, land uses and their changes were categorized between 1980 and 2006, and the ecosystem services capital and changes of 111 counties of Shandong Province in different phases were evaluated, as well as the total ecosystem services capital, followed by the zoning of ecosystem services function region of Shandong Province. We found that the counties in mountainous areas and wetlands, where generally the prefectural-level cities are located with a rapid socioeconomic development, experienced a successive deterioration of ecosystem services especially during the 2000s. Finally, three conservation strategies for managing and improving ecosystem services were proposed and discussed with the aim of achieving coordinate and sustainable development of the socioeconomy, environment, and ecosystems not only in Shandong Province but also in other provinces of China, as well as in other developing and transitional countries and regions.  相似文献   
555.
Both the net primary productivity (NPP) and the normalized difference vegetation index (NDVI) are commonly used as indicators to characterize vegetation vigor, and NDVI has been used as a surrogate estimator of NPP in some cases. To evaluate the reliability of such surrogation, here we examined the quantitative difference between NPP and NDVI in their outcomes of vegetation vigor assessment at a landscape scale. Using Landsat ETM+ data and a process model, the Boreal Ecosystem Productivity Simulator, NPP distribution was mapped at a resolution of 90 m, and total NDVI during the growing season was calculated in Heihe River Basin, Northwest China in 2002. The results from a comparison between the NPP and NDVI classification maps show that there existed a substantial difference in terms of both area and spatial distribution between the assessment outcomes of these two indicators, despite that they are strongly correlated. The degree of difference can be influenced by assessment schemes, as well as the type of vegetation and ecozone. Overall, NDVI is not a good surrogate of NPP as the indicators of vegetation vigor assessment in the study area. Nonetheless, NDVI could serve as a fairish surrogate indicator under the condition that the target region has low vegetation cover and the assessment has relatively coarse classification schemes (i.e., the class number is small). It is suggested that the use of NPP and NDVI should be carefully selected in landscape assessment. Their differences need to be further evaluated across geographic areas and biomes.  相似文献   
556.
红枫湖水库水体富营养化及浮游植物群落结构特征   总被引:6,自引:2,他引:4  
2008-2009年通过对红枫湖水库浮游植物及环境因子进行采样调查,并运用综合营养状态指数对红枫湖水库营养状态进行评价.研究结果显示,红枫湖水库浮游植物全年以蓝藻、绿藻为主的优势种群落,且在2008-2009年经常性局部发生蓝藻水华:冬、春季节主要是水华束丝藻(Aphanizomenon flos-aquae)的蓝藻水华;夏季主要是微囊藻属(Microcystis)蓝藻水华;秋季浮游植物主要是颗粒直链藻(Melosira)和小环藻属(Cyclotella)为主的硅藻类群,未出现水华现象.通过综合营养状态指数计算得红枫湖水库水体水质处于富营养化状态.  相似文献   
557.
杭州地区农业土壤中重金属的分布特征及其环境意义   总被引:1,自引:0,他引:1  
为了分析杭州地区农业土壤重金属的分布特征及其环境意义,通过现场采样和室内分析检测的方法,对杭州市各区县不同作物农业土壤表层土中的Hg、As、Cu、Pb、Cr、Cd 6种重金属元素进行检测,并对其分布特征进行了分析。结果表明,杭州地区农业土壤中除As外,其他5种重金属的平均含量均低于且接近浙江省土壤背景值,个别采样点的重金属含量超过了土壤环境质量国家二级标准。总体上,杭州地区农业土壤处于安全水平。通过重金属的区域分布特征分析表明,余杭区和富阳市农业土壤中重金属平均含量普遍高于其他区域。萧山区和建德市部分农业土壤则存在Cu和Hg含量较高的情况,而淳安县农业土壤中重金属含量差异较大,土壤中出现了As、Cr和Cd含量最大值。不同作物的农业土壤重金属含量存在一定的差异,但不明显。水稻田和蔬菜地的土壤中,重金属含量较其他作物种植类型的土壤中含量高;叶菜类(蔬菜、茶叶)作物土壤中的Cd含量要比根茎类(水稻)、茄果类(水果)及其他作物种植类型的土壤中的含量低。目前杭州地区土壤中6种重金属含量均对作物的直接危害不大,但由于萧山区个别采样点Cu含量严重超标,淳安县土壤中Cd受外源性来源影响也已较明显,需要相关部门加大监管力度,防止污染事件发生。同时,为防止农业土壤中重金属含量进一步升高,需要加大大气降尘监测与治理、废气污染监管与控制治理。  相似文献   
558.
根据GB/T 15000.3—2008设计了苯系物标准气体的时间稳定性研究方案,制备了4瓶苯系物标准气体,随着时间的推移进行测定并将结果制图,结果显示量值随时间没有显著的变化趋势。以线性关系为模型,计算线性直线的斜率和斜率的标准偏差,用t检验判断斜率是否显著来评价标准气体的稳定性。计算结果显示,所有斜率均不显著,因此该研究制备的苯系物标准气体能够稳定保存22个月。根据时间稳定性数据计算由不稳定性引起的不确定度,并讨论了这种计算不稳定性引起不确定度的方法对结果有放大的可能性。  相似文献   
559.
北京市地下水污染源荷载影响评价   总被引:1,自引:0,他引:1  
在阐述地下水污染源荷载影响基本概念的基础上,介绍了污染源荷载影响评价的3大要素:污染荷载等级、含水层敏感性及地下水价值,说明了评价体系、指标和方法及过程。根据主要污染源荷载分析,结合地下水环境现状,对北京市进行了分区,提出污染源管理措施。  相似文献   
560.
Due to the widespread use of pesticides, human exposure to pesticides is possible and can potentially cause adverse impacts on public health. We measured 137 pesticides including organophosphorus, organochlorine, pyrethroid and carbamate pesticides together with various herbicides in 100 human blood samples collected from the general population in Beijing. The samples were analysed by triple quadrupole tandem gas chromatography-mass spectrometry. In total, 24 organochlorine pesticides, 5 pyrethroid pesticides and 6 organophosphorus pesticides were detected. The detection rates of HCB, α-HCH, β-HCH, γ-HCH, p,p′-DDE and quintozene were 99, 96, 74, 72, 96 and 95%, respectively. No statistically significant gender difference in the blood concentrations of the pesticides was found. Consistent with the trend of the increasing β-HCH, p,p′-DDE and quintozene concentrations with age, a strong positive correlation between the age and concentrations of β-BHC, p,p′-DDE and quintozene was observed.  相似文献   
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