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101.
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103.
商业SCR烟气脱硝催化剂钙中毒研究 总被引:1,自引:0,他引:1
使用2种不同浓度的前驱体溶液(Ca(NO3)2和Ca(CH3COO)2溶液)浸渍新鲜商业SCR(selective catalytic reduction)烟气脱硝催化剂,并对浸渍中毒后催化剂的性能进行了研究。实验结果表明,物理中毒在本研究中占主导位置,化学中毒并不明显。采用离子色谱、氮气吸附-脱附分析、红外光谱分析、X射线衍射分析、扫面电镜分析等多种表征技术对中毒后催化剂进行了表征。结果表明,中毒后催化剂孔结构性质发生了变化,特别是Ca(CH3COO)2溶液浸渍催化剂,内部孔道堵塞较为严重。X射线衍射分析和扫描电镜分析也从另一方面说明了CaCO3的出现及积累导致催化剂脱硝效率降低。此外,催化剂红外光谱分析从表面活性位的角度说明了本研究催化剂化学中毒现象并不明显。 相似文献
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105.
The influence of neighborhood traffic density on the respiratory health of elementary schoolchildren
Background
Several studies have found that living near major roadways is associated with an increase in respiratory illness but few studies have measured the volume and type of traffic.Objective
We investigated the relation between traffic volume and respiratory health of 2328 children 9 to 11 years old in the city of Windsor, Canada.Methods
We identified the roadways within a 200 meter radius of the child's neighborhood using the latitude and longitude of the residential postal code. Traffic exposure was defined as the sum of the annual volume of vehicles on all of these roadways. Volume was calculated using sensors to detect passing vehicles (simple traffic counts), and by counts and direction of traffic at intersections (turning movement counts). Ventilatory lung function was measured by spirometry and airway inflammation by exhaled nitric oxide (eNO).Results
The odds ratio between an interquartile increase in truck turning movement counts and chest congestion was 1.20 (1.06-1.35). The percentage of predicted FVC declined 0.68%, (95% CI 1.32, 0.03) for an interquartile increase in simple traffic counts (33,787 vehicles daily). Among those with self-reported asthma, effect sizes were larger. Percentage predicted FEV1 declined 1.84% (95% CI 0.07, 3.61) associated with an interquartile range increase in turning movement counts. No statistically significant change was detected between traffic measures and exhaled nitric oxide.Conclusions
Our findings provide further support for the hypothesis that neighborhood exposure to traffic-related air pollution increases respiratory symptoms and reduces ventilatory function in children, especially those with self-reported asthma. 相似文献106.
Löfgren S Aastrup M Bringmark L Hultberg H Lewin-Pihlblad L Lundin L Karlsson GP Thunholm B 《Ambio》2011,40(8):836-856
Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this
study, we use 1996–2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition
has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water,
groundwater and runoff. Differences in recovery rates between catchments, between recharge and discharge areas and between
soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends
were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem
to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers,
dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged. 相似文献
107.
Jian-Ling Fan Zheng-Yi Hu Noura Ziadi Cong-Yang-Hui Wu 《Environmental pollution (Barking, Essex : 1987)》2010,158(2):409-415
Human activities have resulted in cadmium (Cd) and sulfur (S) accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of excessive S supply on iron plaque formation and Cd accumulation in rice plants, using two Cd levels (0, 1.5 mg kg−1) combined with three S concentrations (0, 60, 120 mg kg−1). The results showed that excessive S supply significantly decreased Cd accumulation in brown rice due to the decrease of Cd availability and the increase of glutathione in rice leaves. But excessive S supply obviously increased Cd accumulation in roots due to the decrease of iron plaque formation on the root surface of rice. Therefore, excessive S supply may result in loss of rice yield, but it could effectively reduce Cd accumulation in brown rice exposed to Cd contaminated soils. 相似文献
108.
煤气作为一种二次能源,是城市中使用的主要能源之一.燃气行业的生产、输送、使用过程,从某种角度来讲是高危的作业过程.煤气网管系统的施工和维护过程中充满了种种困难和危险,造成了许多重大损失,其主要原因是缺乏有效的组织引导和规范的安全措施.本文着重分析了煤气网管系统发生泄露事故的原因,提出了煤气网管系统的运行和维护过程中应当遵循的安全事项和采取的安全措施,为煤气网管系统的运行和维护工作提供了理论依据. 相似文献
109.
石油石化行业工艺复杂,存在的有害因素种类繁多,一旦发生急性中毒其涉及面广、影响大,有时可造成严重危害。文章较为详细地介绍了该行业存在的主要有毒物质以及发生急性中毒事故的必要条件和特点,阐述了有毒物质侵入人体的途径主要为直接接触或通过呼吸,最后针对一般情况、吸入性中毒、直接接触造成危害的情况介绍了相应的现场急救处理措施。 相似文献
110.
职业性有机溶剂中毒特点及防治对策探讨 总被引:3,自引:0,他引:3
随着有机溶剂应用的日益广泛,职业性有机溶剂中毒事件频繁发生。通过分析近年来的职业性有机溶剂中毒事故,探讨了职业性有机溶剂中毒的特点,并对如何有效预防职业性有机溶剂中毒提出了初步的建议,如可以通过改革工艺,加强通风排毒等措施来预防职业性有机溶剂中毒。 相似文献