The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China

Air concentrations of volatile organic compounds (VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and 9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most (36.15%) to the total propene-equivalent concentration of the measured VOCs, followed by combustion emission (16.92%), vegetation emission and secondary formation (14.33%), solvent usage (10.59%), petrochemical industry emission (9.89%), petrol evaporation (6.28%), and liquefied petroleum gas (LPG) usage (5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O₃ formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics, e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O₃ pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O₃ pollution in Shenyang.     

黄河原水中消毒副产物前体物的组成特征及其化学预氧化处理效果对比

以取自河南省郑州市石佛原水厂的黄河原水为研究对象,系统研究了原水中消毒副产物(DBPs)前体物的组成规律,对比分析了3种预氧化剂(高锰酸钾、自由氯和二氧化氯)对原水中DBPs生成潜能的消减规律.试验结果表明:原水中DBPs的前体物均以小分子有机物和疏水性组分(52.51%)为主;分子量小于1 k Da有机物组分是生成含氮消毒副产物(N-DBPs)和三卤甲烷(THMs)的主要前体物;疏水性有机物是生成THMs的主要前体物,亲水性有机物是生成N-DBPs的主要前体物.经Cl2预氧化后,直接生成的DBPs随着自由氯投加量的增加而增加,Cl O2和KMn O4预氧化直接增加DBPs产生量.经3种预氧化剂氧化后,原水中三卤甲烷生成潜能(THMFP)均呈现一定的下降,其降低量依次为Cl O2Cl2KMn O4;然而3种预氧化剂都不能有效的减少含氮消毒副产物生成潜能(N-DBPFP),Cl O2预氧化和Cl2预氧化可增加N-DBPs生成潜能,尤其在较高投加量下,Cl2预氧化将大大增加N-DBPs生成潜能.为有效消减总DBPs生成潜能,水厂可优先采用KMn O4或Cl O2作为预氧化剂处理引黄水库或沉砂池水.     

威远县地质灾害发育规律及成因分析

威远县地质灾害活动频繁,崩塌和滑坡等地质灾害分布广泛。通过对威远县地质灾害分布特征的研究发现,研究区地质灾害点多,但其分布具有一定的区域性,主要分布在低山区。针对这一特性,以威远构造特征为背景,结合区域地质灾害调查资料,分析地质灾害发育的影响,得出背斜构造不仅为地质灾害的发生提供构造条件,而且控制着研究区内的地貌格局,地层岩性是决定地质灾害发育的物质基础。通过本次研究将进一步了解该区地质灾害发育规律及形成原因,对该区地质灾害防治工作提供理论指导。     

跌水曝气生物滤池的挂膜与启动研究

为实现污水的无能耗处理,根据"跌水曝气式生物滤塔"专利设计制作了5层跌水曝气生物滤池,对其在生活污水处理过程中的自然挂膜过程进行研究,分析了挂膜过程中生物相的变化及对COD、NH4+-N的去除效果。试验结果表明:COD的去除主要集中在滤池的中上部(第1、2、3滤料层),而对NH4+-N的去除主要集中在中下部(第4、5滤料层)。当COD的去除率稳定在61.5%左右,NH4+-N的去除率稳定在56%以上,且滤料中的生物相趋于稳定时,标志着反应器挂膜已完成,历时约21 d。     

分离高浓度污泥产酸发酵液的自生动态膜形成机制

采用自生生物动态膜分离高浓度污泥发酵液,研究了动态膜的形成过程及其对污泥发酵液的分离效果.结果表明,自生动态膜的形成过程受污泥浓度的影响较小,污泥浓度仅影响初始膜通量,不影响稳定时的膜通量.膜通量随着滤布孔径和搅拌速度的增大而增大.动态膜的形成过程符合死端过滤模型,分别由以下4个过程构成:先通过与膜基材孔径相似的污泥颗粒堵塞膜基材孔,其后在膜基材上形成单层污泥,进而在膜基材上形成多层污泥,最后,大颗粒污泥继续沉积到污泥层上.动态膜形成后,对污泥颗粒和溶解性COD(SCOD)的截留率分别为98%和28%,对挥发性脂肪酸(volatile fatty acids,VFAs)的渗透率在82%以上,胞外聚合物(extracellular polymeric substances,EPS)中的蛋白质是动态膜的主要成分.     

城乡统筹中新型城市形态创制的要素关系

在中国，城乡统筹作为整体发展的一个基本机制，一方面反映了社会主义共同富裕的道义原则，另一方面也是由城市和农村的各自状况及其相互关系所规定的必然要求。与此相一致．新型城市形态既是一个发展理念．也是一个具体的建设内容和文明形态．它所表明的就是城市本身在城乡统筹的具体实施中逐步生成的整体形态特征。作为自觉的发展理念和建设实践．新型城市形态至少需要针对几个主要的要素关系进行相应的政策、制度、甚至法律创制。对此。本文指出并说明了以下主要几个方面：①同一辖区内不同行政级别之间的政府职能及行为关系：②本地（或常驻）居民与外来（或流动）农村人员的关系；③不同社会群体与发展取向的关系；④城市内部在形象塑造中的精抻面貌、生活方式、消费导向、开放态度，以及行政划分和政策连接等方面的城乡关系。     

Prevalence of Conservation Design in an Agriculture-Dominated Landscape: The Case of Northern Indiana

We examined the prevalence of residential development that occurs with consideration of the natural features of the site, known as conservation design, within county-level planning jurisdictions across Northern Indiana. Using data from telephone interviews with representatives of planning departments, jurisdictions were ranked based on reported use of conservation design. Three categories of use emerged from the data: no use, use of individual practices associated with conservation design, and integration of multiple conservation design practices. Qualitative data analysis revealed that conservation design practices were not being used widely and, when used, were often used to fulfill stormwater requirements. Statistical analysis, using data from interviews, spatial data sets, and the U.S. Census Bureau, identified several significant positive predictors of the levels of conservation design use including conversion of forest or agricultural land cover to urban uses and education levels in the jurisdiction. Many of the interviewees noted that agricultural land is perceived to meet open space needs within their counties. Given that agricultural land does not fully meet all ecosystem needs, education about the benefits of other types of open space is suggested.

History Matters: Relating Land-Use Change to Butterfly Species Occurrence

Western European landscapes have drastically changed since the 1950s, with agricultural intensifications and the spread of urban settlements considered the most important drivers of this land-use/land-cover change. Losses of habitat for fauna and flora have been a direct consequence of this development. In the present study, we relate butterfly occurrence to land-use/land-cover changes over five decades between 1951 and 2000. The study area covers the entire Swiss territory. The 10 explanatory variables originate from agricultural statistics and censuses. Both state as well as rate was used as explanatory variables. Species distribution data were obtained from natural history collections. We selected eight butterfly species: four species occur on wetlands and four occur on dry grasslands. We used cluster analysis to track land-use/land-cover changes and to group communes based on similar trajectories of change. Generalized linear models were applied to identify factors that were significantly correlated with the persistence or disappearance of butterfly species. Results showed that decreasing agricultural areas and densities of farms with more than 10 ha of cultivated land are significantly related with wetland species decline, and increasing densities of livestock seem to have favored disappearance of dry grassland species. Moreover, we show that species declines are not only dependent on land-use/land-cover states but also on the rates of change; that is, the higher the transformation rate from small to large farms, the higher the loss of dry grassland species. We suggest that more attention should be paid to the rates of landscape change as feasible drivers of species change and derive some management suggestions.     

秦皇岛市泥石流发育特征及防治措施

近年来,随着社会经济的发展,人类工程活动频繁,泥石流地质灾害在我市每年新增灾害中占有相当大的比重,严重威胁着人民的生命财产安全。秦皇岛市泥石流主要发育在北部低山丘陵区,规模小,危害大。通过对泥石流发育特征的研究,阐明其形成条件与地形、地质环境、植被和降雨等因素的关系,并据此提出了群测群防,加强采矿活动正确管理、工程治理等防治措施。