广州市大气气态总汞含量季节和日变化特征

利用高时间分辨率自动测汞仪(tekran 2537B),于2010-11~2011-11对广州市大气气态总汞(TGM)进行了连续1a的观测.结果表明,广州市大气气态总汞的年平均含量为(4.86±1.36)ng/m3,表明该地区受到了一定程度的大气汞污染.TGM浓度按季节表现为:春季>冬季>秋季>夏季.TGM污染呈现春高夏低的现象,气象因素如边界层、静止风是影响其季节分布不同的主要原因.日变化趋势为中午最低,早晚出现2个高峰,边界层和温度对TGM日变化有很大影响.对广州市大气气态汞的可能来源分析结果表明,TGM主要来源于本地人为排放,其中市内燃煤电厂和水泥厂等人为源排放可能是广州市大气气态总汞的主要来源.     

基于核示踪的深圳市农用土壤侵蚀特征及评价

运用137Cs和210Pb_ex联合示踪技术,考察深圳特区内外典型区域137Cs和210Pb_ex面积活度的背景值与变化特征,以及典型区农用土壤侵蚀速率、分布特征和主要影响因素. 结果表明:①在城市化剧烈的人为扰动作用下,深圳市的地表土壤环境已经大部分不具备自然土壤的基本属性. 深圳市137Cs面积活度背景值介于99~653Bq/m2之间,仙湖植物园的137Cs实测面积活度背景值最大〔为(653±81)Bq/m2〕,南澳新大村的137Cs实测面积活度背景值最小〔为(99±47)Bq/m2〕. ②随着海拔升高,210Pb_ex的实测面积活度背景值呈增加趋势,这和低纬度地区亚热带海洋性季风气候的水汽运动有关. ③深圳市南澳新大村和公明水库陡坡农用地种果造成的土壤侵蚀已达到了极剧烈的程度,土壤平均侵蚀速率分别高达6150和40530t/(km2·a). 深圳市农用土壤侵蚀具有分布面积广、人为扰动较剧烈、产流产沙集中、侵蚀强度较大等特征. 人为扰动主导的土地开发与陡坡种果是造成城市水土流失的主要影响因素. ④深圳市近30年来快速城市化活动加速了城市土壤侵蚀的发生和发展,亟待加强开发建设项目水土保持、陡坡还林还草等生态治理工作.      

唐山市大气环境治理措施的效果及分析

为揭示河北省唐山市大气环境治理的措施效果,分析了“十一五”期间唐山市的减排措施、污染物排放量和空气污染物浓度的变化. 结果表明:“十一五”期间(2005—2010年),烟尘、工业粉尘、SO₂排放量分别减少35%、57%、20%,ρ(PM₁₀)、ρ(SO₂)、ρ(NO₂)年均值分别下降12%、33%、33%. 与GB 3095—2012《环境空气质量标准》相比,2005年ρ(PM₁₀)、ρ(SO₂)、ρ(NO₂)分别超标36%、42%、7%,而到2010年ρ(SO₂)、ρ(NO₂)已达标,但ρ(PM₁₀)仍然超标20%. 2008年北京奥运会期间的减排措施使得唐山市ρ(PM₁₀)、ρ(SO₂)、ρ(NO₂)年均值均显著下降,分别比2007年下降13%、20%、28%. 2008—2009年的全球经济危机使得2009年地方生产总值增速较其他年均值降低13%,2009年烟尘和SO₂排放量也呈显著下降趋势,二者比2008年分别下降14%和10%,但工业粉尘排放量反而增加8%. 经济危机使ρ(PM₁₀)、ρ(SO₂)、ρ(NO₂)下降速率分别提升了20%、2%、2%. 研究结果表明,“十一五”总量减排、2008年北京奥运会期间的治理措施和全球经济危机对唐山市的空气质量产生了明显的影响.      

青岛市城市绿地种子植物区系的构成特征

在资料分析和2013年夏秋二季进行的实地调查基础上研究了青岛市城市绿地种子植物区系的科属种构成、种的生活型构成、属的地理分布区类型构成,并比较了青岛市城市绿地种子植物区系与青岛崂山种子植物区系、中国种子植物区系属的地理分布区类型构成差异。结果表明,青岛市城市绿地种子植物区系有种子植物69科155属228种,有含5种及以上的12个较大科、124个单种属、183种木本植物和45种草本植物,有热带分布属32属、温带分布属95属、世界分布属14属和中国特有属14属。青岛市城市绿地种子植物区系有植物种类丰富多样,木本植物种类多,区系中属、种的分化程度高,属的地理分布区类型多样且具有很典型的温带特征和鲜明的中国特色等特点。     

A study on vertical greening practice emphasizing ecological benefits in Xiamen City of China

Through the practice of vertical greening, which is an important method for modern city greening, a city’s natural geographic conditions and rich plant resources can be efficiently utilized. Using vertical greening to shape the characteristics of a city is a promising method for sustainable development. Integration of vertical greening with urban characteristics offers huge ecological and cultural benefits. Vertical greening was adopted in China much later than other developed cities in the world and is still in the exploratory stage in most of the cities. As one of the pioneer cities to carry out vertical greening in China, Xiamen has managed to project it as one of the city highlights. In this study, we analyzed the problems that Xiamen City faced during its development and the important role vertical greening has played in the urban landscape. In addition, humanistic and ecological benefits of vertical greening are illustrated through an experimental study.     

Mitigation of the heat island effect in urban New Jersey

Implementation of urban heat island (UHI) mitigation strategies such as increased vegetative cover and higher-albedo surface materials can reduce the impacts of biophysical hazards in cities, including heat stress related to elevated temperatures, air pollution and associated public health effects. Such strategies also can lower the demand for air-conditioning-related energy production. Since local impacts of global climate change may be intensified in areas with UHIs, mitigation strategies could play an increasingly important role as individuals and communities adapt to climate change. We use CITYgreen, a GIS-based modeling application, to estimate the potential benefits of urban vegetation and reflective roofs as UHI mitigation strategies for case study sites in and around Newark and Camden, New Jersey.

The analysis showed that urban vegetation can reduce health hazards associated with the UHI effect by removing pollutants from the air. Less affluent, inner-city neighborhoods are the ones in which the hazard potential of the UHI effect is shown to be greatest. However, these neighborhoods have less available open space for tree planting and therefore a lower maximum potential benefit. As the climate warms, these neighborhoods may face greater consequences due to interactions between the UHI effect and global climate change. Results also show that urban vegetation is an effective and economically efficient way to reduce energy consumption and costs at the sites.     

Hazard vulnerability assessment: How well does nature follow our rules?

Vulnerability is a central construct in environmental risk assessment, and a variety of methods have been introduced to facilitate its expression as a planning and decision-making device. The contrasting interpretations generated by these methods of modelling produce dramatic differences in spatial representation that contribute to uncertainty, and no clear connection has been established between vulnerability and the actual consequences resulting from a nature hazard event. In this study, geographic information system-based vulnerability modelling is evaluated, and the association between modelled-produced expressions and the aftermath impact of a natural hazard event on the human landscape is examined. Employing hurricane aftermath data from the 2005 Hurricane Katrina event in New Orleans, Louisiana, this study presents a comparative analysis that can assist in the validation of vulnerability assessment methods and identify limitations in current modelling strategies. The results of this analysis demonstrate that the methods employed to model vulnerability do not necessarily capture the actual consequence of a natural hazard event and suggest that place-specific factors should play a more significant role when assessing hazard vulnerability.     

城市生态可持续性的内涵及其支持系统评价指标体系研究

构建城市生态可持续性支持系统评价模型并对其发展水平进行综合评价,是城市生态可持续性从理论研究阶段进入可操作的实际应用阶段的重要步骤。针对城市生态可持续性基本内涵,根据＂承载力-支持力-吸引力-延续力-发展力＂（CSAED）模型框架,构建城市生态可持续性支持系统的评价指标体系,以泛长株潭地区为例,分析了该区域各地市在生态环境有效改善、资源能源集约利用、社会民生和谐进步、经济高效公平增长、人口质量综合提升、政策和制度调整与完善等方面的基本情况与提升方向。评价结果表明：泛长株潭地区大部分城市生态环境有效改善水平、资源能源集约利用效率、社会民生进步程度以及经济高效公平增长水平都普遍偏低,这意味着当前该区域亟需解决城市生态承载力不够强、环境容量有限、产业结构仍待升级、就业结构不优及公共服务不足等区域经济社会发展不协调问题,以维持区域城市生态可持续性。     

梅州城区植物群落的结构特征

2009年4—10月,采用群落调查法、主成分分析法对梅州城区5种绿地类型65个种植的植物群落进行研究,结果表明：1）各类植物共计43科105属147种（含变种）,其中乔木62种（42．17％）、灌木45种（30．61％）、草本植物31种（21．09％）、藤本植物9种（6．12％）;2）群落垂直结构为乔、灌、草3层复合结构者9个（13．85％）,为乔、草2层结构者34个（52．31％）,乔或草单层结构者12个（18．46％）;3）乔木树种平均胸径16．7cm,其中平均胸径〈10cm者23种（37．09％）,平均胸径10～20cm者29种（46．77％）,平均胸径20～30cm、〉30Cm者分别为5种（均为8．06％）;4）梅州城区植物群落结构的特征,可用乔木高度因子、胸径因子、密度因子及冠幅因子来表述,这4个主因子的方差累积贡献率达到81．55％,可以很好地反映出群落结构的大部分信息;5）梅州市城区乔木层的优势树种是垂榕、大叶榕、大王椰子,次优势种是阿珍榄仁、阴香、海南蒲桃、细叶榕、木棉、麻楝、香樟、洋紫荆,这11个树种分属桑科、棕榈科、使君子科·、樟科、桃金娘科、木棉科、楝科、豆科（云实科）,它们是梅州城市森林的骨干树种和基调树种,决定了梅州城市森林的南亚热带性质的外貌。     

漳州市绿地有机质和磁化率特征及其相关性

对漳州市的公园绿地、道路绿地、单位附属绿地和居住区绿地的有机质含量和磁学特征进行了分析,结果表明漳州市城区绿地有机质含量波动范围较大,土壤样品有机质含量的平均值是12.47 g/kg,变化范围为2.27～27.79 g/kg,不同绿地功能区有机质含量为单位附属绿地道路绿地公园绿地居住区绿地。土壤样品的平均磁化率值为300.39×10-8 m3/kg,频率磁化率平均值为1.58%,土壤呈现明显的磁性增强,不同绿地功能区土壤磁化率值为居住区绿地道路绿地单位附属绿地公园绿地;有机质与磁化率的相关性较弱,基本上不存在土壤发生学上的联系。由于工业排放,汽车尾气等人类活动的影响,原始土壤已经严重破坏,土壤组成复杂,大量外来物质入侵,漳州市城市绿地表现出明显的人为扰动特征,并且可能受到一定程度的重金属污染。