Online monitoring of water-soluble ionic composition of PM10 during early summer over Lanzhou City

Lanzhou is one of the most aerosol-polluted cities in China. In this study, an online analyzer for Monitoring for AeRosols and GAses was deployed to measure major water-soluble inorganic ions in PM10 at 1-hour time resolution, and 923 samples were obtained from Apr 1 to May 24, 2011. During the field campaign, air pollution days were encountered with Air Quality Index more than 100 and daily average concentration of PM10 exceeding 150 μg/m3. Based on the variation of water-soluble ions and results of Positive Matrix Factorization 3.0 model execution, the air pollution days were classified as crustal species- or secondary aerosol-induced, and the different formation mechanisms of these two air pollution types were studied. During the crustal species pollution days, the content of Ca2+increased and was about 2.3 times higher than the average on clear days, and the air parcel back trajectory was used to analyze the sources of crustal species. Data on sulfate, trace gases and meteorological factors were used to reveal the formation mechanism of secondary aerosol pollution. The sulfur oxidation ratio(SOR) was derived from the 923 samples, and the SOR had high positive correlation with relative humidity in early summer in Lanzhou.     

兰州市大气OPAHs污染特征及潜在来源分析

对兰州市冬季（2016-12-01~07）和夏季（2017-08-03~10）大气气相和颗粒相（PM_1.0、PM_2.5和PM₁₀）中含氧多环芳烃（OPAHs）进行观测,结果显示：Σ₈OPAHs （气相+颗粒相）的浓度范围为1.83~19.28ng/m³,平均浓度为（6.45±3.43） ng/m³.冬季是夏季的2.06倍.冬季颗粒相OPAHs在2.5~10和<1.0μm粒径段均具有较大占比,而夏季则主要赋存于PM_1.0中.9-芴酮（9-FLU）、9,10-蒽醌（9,10-ANT）和苯并蒽酮（BZA）为OPAHs中最主要的几种单体物质,其占比为51.8%~94.9%.气粒分配机制研究结果表明：OPAHs在气粒两相间的分配以吸收机制为主导.基于浓度权重轨迹分析法（CWT）对兰州市大气中OPAHs的潜在污染源区进行了分析,发现其潜在污染源区在冬季主要位于当地及其西北方向位于新疆和青海境内的部分地区,而夏季则主要位于该研究区域的东南方向（定西市、天水市等）和东北方向（宁夏回族自治区中卫市）.     

兰州市大气重污染气象成因分析

兰州市曾经是全国乃至全世界空气污染最严重的城市之一,重度空气污染特征明显.根据兰州市环境保护局公布的大气污染数据及气象局的气象观测数据,采用时间序列法和相关统计方法对兰州市2002—2011年空气污染指数(Air Pollution Index,API)大于200的大气重污染特征进行研究,并探析了其气象学成因.结果表明,静稳型重污染发生天数约占重污染发生总天数的77%,而沙尘型重污染只占23%.静稳型重污染是兰州市最主要的大气重污染类型,它往往存在PM10、SO2和NO2三种污染物同步累积的过程,持续时间长,主要发生在冬季;而沙尘型重污染持续时间短,由于外来高浓度沙尘输送的影响,PM10浓度会急剧升高,而SO2和NO2浓度则会明显下降(SO2、NO2浓度明显低于静稳型重污染),几乎都发生在春季.对它们的成因分析表明:静稳型重污染的气象学成因主要是风速小,稳定能量大,大气环境稳定度大,不利于湍流扩散,本地源污染物持续积累造成;沙尘型重污染气象学成因主要是春季气候干燥,相对湿度低,造成大风沙尘天气,给兰州市输送大量沙尘颗粒形成大气重污染.此研究结果可为兰州市大气重污染的防治提供科学依据.     

兰州基本退出十大污染城市行歹

甘肃省兰州市政府日前召开2013年环保目标责任完成情况汇报会。兰州市目前已超额完成甘肃省下达的各项环保目标任务：环境质量明显改善，优良天数大幅增加，空气综合污染指数同比下降，已基本退出全国十大污染城市行列。     

Optimizing Urban Spatial Structure of Lanzhou Based on Geographic Concentration Method of Industries

Geographic concentration of industries is the regionalized distribution of some industries in certain areas, which focuses on the ratio of a certain industry to the whole industries （He and Liu, 2006）. In this paper we explore the improved M function of geographic concentration that adds the parameter of the number of firms according to the definition of geographic concentration of industries. The spatial distribution of the main manufacturing industries of Lanzhou urban area is evaluated based on it. The results of the evaluation imply that the spatial distribution of the main manufacturing industries is more concentrated than that of others in Lanzhou and it can absorb lots of labor forces. But the incidence, competition ability and density of the distribution of enterprises are different for each single sector, and enterprises with different production features are located closely. And three main problems are discovered. Finally, three countermeasures are put forward： locating the industrial enterprises in urban areas in a proper way through planning and policies; adjusting the industrial structure of the inner city; strengthening the local rearrangement of the existing industrial concentration areas.     

兰州市人居环境与经济发展协调性评价

根据兰州市城市人居环境与经济方面的实证资料,构建兰州市人居环境和经济系统的评价指标体系,采用SPSS软件、主成分分析方法和协调度、协调发展度模型分别求出1999-2010年城市人居环境与经济系统的协调发展度值,定量分析了兰州城市人居环境与经济协调发展程度.结果显示,1999-2010年兰州市城市人居环境与经济发展的协调度由中度失调发展向良好协调发展阶段转变,两系统之间的协调度呈持续稳步上升趋势,进而提出促进兰州市人居环境与经济协调性发展的对策措施.     

城市绿化树种的选择与配置：以兰州市四固工业区为例

本文以地处中国西北干旱区的兰州市西固工业区为例，考察了该区绿化历史和现状，在此基础上，指出城市绿化树种的选择必须符合当地自然地理特征、城市发展状况、环境污染特征的原则，树种的配置应充分考虑绿化效益的发挥，同时兼顾经济可行性，并对兰州市西固工业区绿化提出了针对性的建议。     

兰州市排水对黄河兰州下游段的水质影响

讨论了黄河兰州下游段水质变化规律，介绍四龙口上断面水质综合评价结论及四个污染项目，着重分析污染项目的污染原因，得出兰州市排水对四个项目污染影响程度的结论。     

兰州市大气污染的现状,原因与对策

通过对兰州市ＳＯ２、ＮＯｘ，ＣＯ，总量浮颗粒物（ＴＳＰ）和降尘这五种主要大气污染物的污染综合指数和污染负荷系数的计算，排出了五种污染污染严重程度的顺序：ＴＳＰ〉降尘〉ＮＯｘ〉ＳＯ２〉ＣＯ；以及一年四季中大气污染严重程度的顺序：一季度〉四季度〉二季度〉三季度。表明兰州市大气污染具有如下两大特点：（１）冬季污染最严重，以“尘污染”为主，是一个典型的“煤烟型”污染城市；（２）ＮＯｘ的污染负荷系数大于ＳＯ