Temporal variations of atmospheric carbonyls in urban ambient air and street canyons of a Mountainous city in Southwest China

Carbonyl compounds in urban ambient air and street canyons were measured from December 2008 to August 2009 in a mountainous city in southwest China (Guiyang). The formaldehyde yield from the photo-oxidation of isoprene emitted by vegetation was estimated to be in the range of 0.63–3.62 μg m^?3 from May to August, which accounted for 28.8–33.4% of ambient formaldehyde. Based on the calculation of photolysis rates and rates of reaction with the OH radical, it was found that photolysis was the predominant sink for formaldehyde and acetone in both summer and winter. For acetaldehyde, photo-oxidation by OH radicals and photolysis were the major sinks in summer while photo-oxidation by OH radicals was the dominant sink in winter. Wet precipitation was found to be an important removal process for the atmospheric carbonyls. In the urban ambient air, the average concentrations of formaldehyde, acetaldehyde, acetone and all carbonyls were 4.8 ± 2.1, 5.7 ± 3.3, 5.1 ± 2.5, and 25.1 ± 9.2 μg m^?3 (n = 139), respectively. The average concentrations of these species in street canyons were 18.8 ± 6.5, 9.4 ± 3.2, 10.9 ± 2.1, and 64.1 ± 16.3 μg m^?3 (n = 62), respectively. The significantly higher carbonyl levels on weekdays (compared to weekends) highlight the contribution of vehicle emissions to carbonyls in the street canyons.     

中国省域能源价格与碳强度协整研究：基于1995～2009年的面板数据

基于面板数据协整检验理论,利用中国华东地区七省域1995～2009年间的数据资料,检验能源价格与碳强度变量序列的平稳性及协整关系,并建立回归模型。结果表明：能源价格与碳强度之间存在长期均衡关系;Hausman检验认为能源价格与碳强度间应建立个体固定效应回归模型;能源价格对碳强度负相关,提高能源价格能显著降低碳强度,但不同地区碳强度对能源价格变化的反应不同;经济较发达的省域,能源价格相对较高而碳强度相对较低。建议适度提高能源价格,加强技术创新、优化能源结构和提升能源效率,积极推进省际产业衔接与协作,促使碳强度不断下降,实现能源、经济和社会可持续发展。     

Measurement of green productivity and its improvement

The measurement framework of the green productivity (GP) of a product system, or process, and its improvement are discussed. Two types of GP indicators are developed to help understand the practical concept and executive approaches of GP, using environmental management tools such as life cycle assessment (LCA) and total cost assessment (TCA). GP index is defined as the ratio of productivity of a system to its environmental impacts. This index is intended for estimating the GP performance of an existing product or process and comparing it with other equivalents. Specifically, the GP index is a measure of the GP performance of a product system throughout its entire life cycle. The “overall” GP index can be divided into a “direct” GP index and an “indirect” GP index which are intended to analyze the GP performances of direct production processes and indirect upstream processes, respectively. For internal managerial decision, GP ratio is developed to select one alternative out of a list of contenders in order to improve the GP performance of an existing system. In addition, GP portfolio is drawn up to check the strengths and weaknesses of alternatives. A case study of a petrochemical company in Korea is provided as an example for illustrating the feasibility of the indicators developed here (GP index and GP ratio) for the measurement of GP and its improvement.     

离子液体与有机磷农药间的毒性相互作用

"绿色"溶剂离子液体(ILs)与其他污染物之间的毒性相互作用已有报道,但相关数据仍较为缺乏。以7种具有不同阴阳离子组成的ILs:溴化丁基吡啶(IL1)、氯化丁基-2,3-二甲基咪唑(IL2)、丁基-3-甲基咪唑翁磷酸盐(IL3)、丁基-3-甲基咪唑正辛基硫酸(IL4)、丁基-2,3-二甲基咪唑二乙二醇单甲醚硫酸盐(IL5)、辛基-3-甲基咪唑二乙基醚单甲磺硫酸(IL6)和氯化己基-3-甲基咪唑(IL7),与5种有机磷农药(OPs):敌敌畏(DIC)、乐果(DIM)、草甘膦(GLY)、久效磷(MON)和磷胺(PHO),作为混合物组分,以等效应浓度比射线法设计7种ILs分别与5种OPs等EC_(50)配比的35组二元混合物,应用微板毒性分析法(MTA)测定这些混合物对青海弧菌Q67的毒性,以浓度加和(CA)和独立作用(IA)为参考模型分析毒性相互作用。结果表明,不同的IL-OP混合物呈现的作用类型不同:如IL1-DIM、IL2-DIM、IL3-DIM、IL6-DIM、IL2-MON和IL7-DIM的混合物呈明显的拮抗作用;IL3-DIC和IL2-GLY的混合物呈明显的协同作用;IL5-DIM和IL4-MON的混合物在较高浓度区呈拮抗作用;而IL3-GLY和IL6-DIC的混合物在较高浓度区呈协同作用;其余的混合物则为加和作用。     

合肥市不同下垫面降雨径流水质特征分析

通过对合肥市4种不同类型下垫面27场降雨径流和自然降雨水样中SS、COD、TN和TP水质指标的分析,探讨了草地、屋面、校内路面和校外道路降雨径流污染物历时变化规律及初期冲刷效应,比较了不同类型下垫面降雨径流和自然降雨水样中污染物浓度分布的差异,计算了场次降雨径流污染物的事件平均浓度.结果表明,不同下垫面降雨径流污染物浓度随时间变化的规律相似,且大多存在初期冲刷现象,一般在降雨初期污染物浓度较高,随着降雨历时的延长污染物浓度呈下降趋势,并趋于平稳;不同下垫面降雨径流和自然降雨水样中TN污染负荷较高,大气湿沉降对降雨径流中TN的贡献很大;校外道路降雨径流水样中SS、COD、TN和TP浓度的变化范围冬半年大于夏半年,不同下垫面条件对降雨径流中污染物EMC的影响存在差异.     

吡啶类离子液体对青海弧菌Q67的混合毒性评估

合污染物产生的累积与毒性相互作用具有潜在的环境与健康风险。以6种吡啶类离子液体(IL)：丁基溴化吡啶([Bpy]Br)、己基溴化吡啶([Hpy]Br)、辛基溴化吡啶([Opy]Br)、丁基氯化吡啶([Bpy]Cl)、己基氯化吡啶([Opy]Cl)和辛基氯化吡啶([Opy]Cl)为混合物组分,应用直接均分射线法(EquRay)和均匀设计射线法(UD-Ray)分别设计4组二元IL混合物和2组三元混合物,每组混合物包括5条具有不同浓度配比的混合物射线。应用微板毒性分析法测定6种IL及其30条混合物射线对青海弧菌Q67的发光抑制毒性,以浓度加和(CA)为加和参考模型分析混合物毒性相互作用。结果表明,Logit函数能有效地拟合6种吡啶IL及其30条混合物射线的浓度-效应数据。若以半数效应浓度的负对数(pEC₅₀)为毒性指标,6个吡啶IL对Q67的毒性与烷基链上碳原子数目正相关,且每增加2个碳原子,其毒性约增加1。IL的阴离子(Br^-或Cl^-)对毒性没有影响。除己基氯化吡啶([Hpy]Cl)和辛基氯化吡啶([Opy]Cl)的二元混合物呈现明显拮抗作用外,其他二元及三元混合物都为加和作用。     

Effect of concentration and ignition position on vented methane–air explosions

Experiments were conducted in a 1 m³ vessel with a top vent to investigate the effect of methane concentration and ignition position on pressure buildup and flame behavior. Three pressure peaks (p₁, p₂, and P_ext) and two types of pressure oscillations (Helmholtz and acoustic oscillations) were observed. The rupture of vent cover results in p₁ that is insensitive to methane concentration and ignition position. Owing to the interaction between acoustic wave and the flame, p₂ forms in the central and top ignition explosions when the methane–air mixture is near–stoichiometric. When the methane–air mixture is centrally ignited, p₂ first increases and then decreases with an increase in the methane concentration. The external explosion-induced P_ext is observed only in the bottom ignition explosions with an amplitude of several kilopascals. Under the current experimental conditions, flame–acoustic interaction leads to the most serious explosions in central ignition tests. Methane concentration and ignition position have little effect on the frequency of Helmholtz and acoustic oscillations; however, the Helmholtz oscillation lasts longer and first decreases and then increases as the methane concentration increases for top ignition cases. The ignition position significantly affects the Taylor instability of the flame front resulting from the Helmholtz oscillation.     

深埋管道中泄漏孔对燃气泄漏影响的数值模拟*

为研究泄漏孔的各种因素对深埋土体中燃气管道泄漏的具体影响,采用1个包含燃气管道的三维模型,研究单个泄漏孔的大小、位置、形状对于埋地燃气管道泄漏的影响,并建立大小相等的双泄漏孔的燃气管道,确定双泄漏孔间距对于燃气泄漏扩散的影响。结果表明:泄漏孔越大,燃气在土壤中的扩散速度越快,且泄漏孔的大小对深埋燃气管道泄漏的影响最大;泄漏孔位置的影响次之,顶部与侧壁的泄漏孔扩散速度相差无几,底部泄漏孔的扩散速度远低于前2者;双泄漏孔间距的影响较小,双泄漏孔的距离越小,甲烷的扩散速度越快;泄漏孔形状对于深埋燃气管道泄漏扩散的影响非常小。     

中国雾霾污染的社会经济影响因素——基于空间面板数据EBA模型实证研究

依据环境经济学理论,运用空间极限边界分析模型,采用中国2003—2013年30个省际面板数据,从经济、人口、政策三方面入手,遴选尽可能多的社会经济变量,探究中国雾霾污染的空间相关性及其影响因素.结果显示中国雾霾污染具有空间溢出效应且京津冀、长三角及中东部部分地区出现高-高集聚现象.产业结构、能源消费结构、城市建筑施工、人口规模以及汽车保有量对雾霾污染具有抗干扰性的"稳健性"影响.最后依据实证结论提出了一些政策建议,如进行雾霾区域联合防治,转变经济发展方式,清洁高效使用煤炭,合理布局城市人口等.这些建议为政府制定治理雾霾政策提供决策依据和参考.