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231.
232.
Particulate air pollution from combustion and construction in coastal and urban areas of China 总被引:1,自引:0,他引:1
Chen B Chen J Zhao J Zhang F 《Journal of the Air & Waste Management Association (1995)》2011,61(11):1160-1165
In China, the areas that are undergoing rapid urban growth are faced with increasingly more complicated air pollution problems. Sources of air pollution need to be identified and their contributions quantified. In this study, PM2.5 (particulate matter with aerodynamic diameters < or =2.5 microm), PM2.5-10 (particulate matter with aerodynamic diameters 2.5-10 microm), organic carbon (OC), and elemental carbon (EC) concentrations were measured from April to July 2009 at four selected areas in Xiamen (the downtown area, an industrial park, a suburb, and one remote site). The contributions of carbonaceous aerosols to PM2.5 and PM2.5-10 were 20-30% and 10-20%, respectively, indicating that finer particles contained more carbonaceous aerosols. The EC concentrations in PM2.5 at the downtown, industrial, suburb, and remote sites were 2.16 +/- 0.61, 2.05 +/- 0.45, 1.69 +/- 0.54, and 0.65 +/- 0.43 microg m-3, respectively, showing a decrease from the urban and industrial hotspots to the surrounding areas. These data show that carbonaceous aerosols emitted from the combustion of fossil fuels in urban and industrial hotspots influence air quality at the regional scale. Higher levels of PM2.5 and PM2.5-10 were observed at the suburb site compared to the urban and industrial sites. Peak EC concentrations in PM2.5 were observed during the morning and evening rush hours. However, peak PM2.5 levels at the suburb site were observed around noon, which coincides with construction work hours, instead of the morning and evening rush hours when emissions from combustion dominated. These findings indicate that both fuel combustion and construction have exacerbated air pollution in coastal and urban areas in China. 相似文献
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The presence of Bacillus thuringiensis (Bt) protein in earthworms Eisenia fetida has no deleterious effects on their growth and reproduction 总被引:1,自引:0,他引:1
Earthworms Eisenia fetida, bred in substances with stover of two genetically-engineered Bacillus thuringiensis (Bt) corns (5422Bt1 (Event Bt11) and 5422CBCL (MON810)) expressing Cry1Ab and their near-isogenic non-Bt corn (5422), were used to investigate the non-target effects of Bt corn on soil-dwelling organisms. Cry1Ab concentrations in substances, casts and guts of E. fetida were also investigated by Enzyme-linked immunosorbent assay (ELISA). More than 90% individuals of E. fetida survived over a period of 30 d, irrespective of whether they received Bt corn or non-Bt corn. Compared to 5422 treatments, significantly higher relative growth rate and more number of new offspring and cocoons of E. fetida were found in 5422Bt1 and 5422CBCL treatments. These results were unlikely to be directly caused by Cry1Ab released from Bt corns but rather by differences in other factors of plants such as plant components (soluble sugar, total organic carbon, total protein and available phosphorus of Bt corns were more than 5422). ELISA results indicated immunoreactive Cry1Ab was detectable in substances, and the casts, guts of E. fetida from Bt corns treatments, of which the highest levels were detected in substances under the corresponding experimental conditions. With the increase of treated time, a strong decline was observed in Cry1Ab from substances and casts of E. fetida, whereas Cry1Ab in guts of E. fetida from 5422Bt1 treatments gradually increased and that from 5422CBCL treatments increased between 14 and 30 d. Therefore, the presence of Cry1Ab in E. fetida had no deleterious effects on their growth and reproduction. 相似文献
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采用共混热解法制备系列Ce-Sn-W-Ox复合氧化物,用于NH3选择性催化还原NO。通过正交实验优化CeSn-W-Ox配方,采用环境扫描电镜(ESEM)、X-射线衍射仪(XRD)等表征分析催化剂的微观形貌和固相结构,确立Ce-Sn-WOx最佳配比及结构形貌。结果表明,以粒度为5~8 mm的堇青石瓷片担载分散Ce-Sn-W-Ox,进行NH3-SCR脱除NO,当Ce/Sn/W元素摩尔比为1∶0.8∶0.6时,Ce Sn0.8W0.6Ox/堇青石NH3-SCR脱除NO效果最好。当空速为7 200 h-1,催化剂在252~426℃内脱除NO效率均大于94%。重点考察了反应空速(GHSV)、水蒸气(H2O)、SO2等对Ce Sn0.8W0.6Ox/堇青石NH3-SCR脱除NO活性的影响。研究表明,空速低于10 000 h-1时,催化剂脱硝活性受空速影响小;单独通入5%H2O对催化剂脱硝活性基本没有影响;单独通入429 mg/m3SO2导致催化剂活性略有降低;同时通入429 mg/m3SO2和5%H2O,催化剂脱硝活性下降至85.33%,除去SO2和H2O后,催化剂活性又能明显回升。 相似文献
238.
Du YB Lee CT Christina D Belfer ML Betancourt TS O'Rourke EJ Palfrey JS 《Disasters》2012,36(3):495-513
The tsunami that struck South-east Asia on 26 December 2004 left more than 500,000 people in Aceh, Indonesia, homeless and displaced to temporary barracks and other communities. This study examines the associations between prolonged habitation in barracks and the nature of fears reported by school-age children and adolescents. In mid-2007, 30 months after the tsunami, the authors interviewed 155 child and parent dyads. Logistic regression analysis was used to compare the fears reported by children and adolescents living in barracks with those reported by their peers who were living in villages. After adjusting for demographic factors and tsunami exposure, the data reveals that children and adolescents living in barracks were three times more likely than those living in villages to report tsunami-related fears. The study demonstrates that continued residence in barracks 30 months after the tsunami is associated with higher rates of reporting tsunami-related fears, suggesting that barracks habitation has had a significant impact on the psychological experience of children and adolescents since the tsunami. 相似文献
239.
基于"脱钩"模式的低碳城市评价 总被引:7,自引:0,他引:7
由于历史及现状等诸多因素,以二氧化碳减排绝对量为基础的低碳城市评价模式并不适用于中国;本研究从经济发展、物质消耗与污染物排放相互关系的视角,以"脱钩"模式为目标层,经济发展、碳排放、污染物排放与经济发展为准则层,CO2排放等8个具体指标为指标层建立低碳城市评价指标体系,定量描述经济发展过程中单位GDP污染物排放降低的态势,进而表征城市发展过程中的经济、资源、环境变化的历史趋势并反映城市低碳建设现状.针对沈阳市的案例研究表明,沈阳市2001年至2008年总体的生态效率与资源利用效率呈现逐渐提高的态势,沈阳市现阶段的低碳城市建设水平处于"相对脱钩"阶段,与目前中国经济宏观发展态势相符合.本研究表明,"脱钩"评价模式可以避免基于污染物总量的评价模式中忽略经济发展因素而产生的片面性,可以表征中国当前经济高速发展前提下的城市低碳建设水平,为目前的"低碳城市"评价方法提供有益尝试. 相似文献
240.
“十二五”期间节能减排的目标是单位GDP能耗下降16%,为实现这一目标,政府采取了以提高能源效率为核心的节能减排政策,但是能源效率的提高可能产生潜在的“回弹效应”,即可能增加能源的使用从而使得节能减排目标难以实现.本文在文献研究的基础上,分析了回弹效应的类型和产生机理,梳理了国内外文献中关于回弹效应测度的实证结果,指出了当前实证研究中存在的主要问题,并从公共政策制定的角度设计了经济模型和其他社会科学相结合的定性比较分析研究方案,主张从经济主体行为反应、替代品价格、能源补贴以及发展新能源政策等多重视角研究回弹效应发生的内在机理,从而对能源政策产生明确的导向.最后,提出了加强能源回弹效应研究的具体政策建议. 相似文献