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51.
The measurements of atmospheric carbonyls concentrations in Beijing were conducted from 12 July to 8 October, 2008, covering the periods of the 2008 Olympic Games and Paralympic Games. Six carbonyls, including formaldehyde, acetaldehyde, acetone, butyraldehyde, valeraldehyde, and hexaldehyde, were identified in all air samples. The total average concentrations of these carbonyls before, during, and after traffic restriction were (48.1 ± 15.2), (36.6 ± 14.5) and (23.4 ± 12.3) μg/m3, respectively. Compared with the period after traffic restriction, the distinct high concentrations of the carbonyls before and during traffic restriction were primarily ascribed to the remarkable contribution of photochemical reactions. With respect to our previous investigation in the summer of 2005, the reductions of formaldehyde, acetaldehyde and acetone during traffic restriction period were about 64%, 47% and 27%, respectively, indicating that the air cleaning actions adopted by the Chinese government for the two games were efficient. The lowest levels of atmospheric carbonyls and the extremely high composition proportion of acetone after the traffic restriction were mainly attributed to the long-term effect of the control measures for the two games. 相似文献
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对比两组填充了离子交换纤维FFA-1的固定床反应器(R1和R2)的运行处理效果,研究负载功能微生物的离子纤维组合工艺对不同浓度As(III)的去除能力.研究结果表明接种了三价砷氧化菌(AsOB)的R1能够长期稳定并高效地去除不同浓度(1~10 mg·L-1)As(III).未接种AsOB的R2反应器初期无法去除As(III),随着微生物逐步侵入R2反应器,7 d后R2反应器As(III)去除率逐渐与R1接近.相对于一直稳定运行的R1反应器,每次提升进水中As(III)浓度后R2去除率呈现先下降后上升的趋势.同时,在运行过程中发现进水中NO3-和SO42-等阴离子也会被R1和R2去除从而导致As(III)去除总量的下降.离子交换纤维FFA-1再生实验证实R1和R2中的纤维与原始的离子交换纤维FFA-1再生效果相当(再生率均达到90%以上).进一步研究微生物种群结构在反应器中的变化发现离子交换纤维作为微生物载体可能是影响微生物种群结构的重要因素.本研究证实了功能微生物AsOB联合离子交换纤维可以作为一种高效去除地下水中三价砷的工艺,具有很好的应用前景. 相似文献
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Chun Chen Yuzheng Wang Yuanyuan Zhang Xiaoxiu Lun Chengtang Liu Yujing Mu Chenglong Zhang Pengfei Liu Chaoyang Xue Min Song Can Ye Junfeng Liu 《环境科学学报(英文版)》2019,31(6):316-326
The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time. 相似文献
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Biogenic volatile organic compounds (BVOCs) in the atmosphere play important roles in the formation of ground-level ozone and secondary organic aerosol (SOA) in global scale and also in regional scale under some condition due to their large amount and relatively higher reactivity. In places with high plant cover in the tropics and in China where air pollution is serious, the effect of BVOCs on ozone and secondary organic aerosols is strong. The present research aims to provide a comprehensive review about the emission rate, emission inventory, research methods, the influencing factors of BVOCs emissions, as well as their impacts on atmospheric environment quality and human health in recent years in Asia based on the summary and analysis of literatures. It is suggested to use field direct measurement method to obtain the emission rate and model method to calculate the emission amount. Several recommendations are given for future investigation and policy development on BVOCs emission. 相似文献
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城市生态经济系统模型构建与分析 总被引:6,自引:1,他引:6
根据城市生态经济系统(UrbanEco-economicSystem,UEES)运行规律和系统调控的目标,建立了UEES指标体系.以宁波市为例,采用偏最小二乘算法构建了UEES模型.本例中,模型的Q2cum值为0·996,表明其具有较好的稳定性和预测能力.计算结果表明,到2007年、2012年和2020年,宁波市国内生产总值将分别达到2588×108元、3250×108元、5261×108元;万元国内生产总值能耗、城市化水平与产业结构是影响经济规模扩大的主要因素,万元工业产值废水排放量和SO2排放量与经济规模呈显著的负相关关系.在此基础上,提出了宁波生态市建设过程中经济发展的若干建议. 相似文献
59.
一株贫营养异养硝化-好氧反硝化菌的筛选及脱氮特性 总被引:5,自引:0,他引:5
为了探究并优化菌剂应用于微污染水源水体修复的机制和条件,主要针对水库沉积物内筛选出的贫营养好氧反硝化菌进行了菌种鉴定及脱氮特性研究,考察菌株在不同环境条件下的脱氮效果,明确了该菌株的最适宜生长条件,并基于水库水体中贫营养条件对菌株进行水源水库原水的驯化培养试验研究,以期实现该菌株对微污染水源水库原水中氮源污染物的脱除,为原位投菌技术实际工程应用提供理论依据。从微污染水源水库沉积物中驯化筛分出一株高效异养硝化-好氧反硝化菌A14,通过扫描电镜观察、生理生化特征、16S rRNA基因测序和Biolog GenⅢ鉴定,确定该菌株为革兰氏阴性短杆菌,鉴定为皮特不动杆菌(Acinetobacter pittii)。在好氧条件下,菌株细胞内表达反硝化功能基因napA,以NO3-为唯一氮源进行反硝化作用时,36 h时NO3-去除率为78.89%。以NH4+为唯一氮源时,48 h NH4+去除率为95.25%,TN去除率达80.42%,TOC去除率达98.30%,表明该菌株具有异养硝化-好氧反硝化特性。在改变环境条件过程中,该菌株在以乙酸钠为碳源,温度为30℃,C/N为12,pH为7,接种量为10%时,NO3-去除率最高为86.62%,并且在10℃下脱氮率达到40.18%。在水源水库原水脱氮实验中,接种处理TN去除率为50.95%,NO3-去除率为80.25%。结果表明,菌株A14在微污染水源水体菌剂脱氮修复中具有良好的应用潜力。 相似文献
60.
牛俊峰 《安全.健康和环境》2006,6(11):28-29
分析溶剂系统结垢的主要危害, 介绍水冲洗及系统试压、碱洗、酸洗、漂洗、中和钝化等化学清洗工艺步骤,应用后取得了良好的效果. 相似文献