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861.
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863.
气溶胶地基观测数据和颗粒物浓度数据的同步定量评估可为了解长安区大气污染的垂直分布特征,制定合理的大气污染控制提供更有效的依据.基于CE-318太阳光度计观测数据,分析了2018年10月~2021年4月西安市长安区月均和季均气溶胶光学特性分布和变化特征,结合近地面颗粒物浓度数据,分析了不同季节、不同污染程度下气溶胶光学厚度(AOD)对颗粒物浓度的响应.结果表明:(1)观测期间长安区AOD季节变化分明:秋季(1.02)>冬季(1.00)>夏季(0.63)>春季(0.47); AOD月度、年际差异大,2019年AOD(0.51)略高于2020年(0.48).(2)整个观测期间长安区气溶胶主控模态存在明显的季节、月度差异,从春季到冬季气溶胶主控模态逐渐从粗模态向细模态转变;2019年气溶胶主控模态的季节变化与整个观测时段类似,2020年各季节气溶胶Angstrom波长指数(Angstrom)分布稳定,气溶胶粒子均以粗模态的形式存在;整个观测时段来看长安区气溶胶类型以混合型气溶胶为主.(3)AOD和Angstrom的关系存在明显的季节差异,春季大气污染以粗模态的气溶胶粒子为主导... 相似文献
864.
基于文献计量分析的长江经济带农田土壤重金属污染特征 总被引:2,自引:1,他引:1
长江经济带是我国重大战略发展区域之一,理清长江经济带农田土壤重金属污染特征与来源对区域土壤重金属污染防控和农业安全生产具有重要意义.在检索文献数据的基础上,结合空间分析和地累积指数法分析了长江经济带农田土壤重金属(Cd、Cr、Hg、As、Pb、Cu、Zn和Ni)的污染特征、环境风险和主要来源.结果表明:①农田土壤Cd、Cu、Pb、Hg、Zn和As超过农用地土壤污染风险筛选值的比例分别为39.8%、18.5%、8.3%、6.9%、6.9%和6.4%,其中土壤Cd的超标比例最高;②不同区域农田土壤重金属空间分异明显,上游土壤Cr、Cu、Zn和Ni含量高于中游和下游地区,中游土壤Cd、As和Pb含量高于上游和下游地区;③研究区8种重金属的地累积指数分别为:Cd (0.42)>Hg (-0.28)>Pb (-0.32)>Zn (-0.39)>Cu (-0.42)>Cr (-0.7)>As (-0.81)>Ni (-0.73),其中土壤Cd和Hg地累积风险最高;④长江经济带中上游地区农田土壤重金属累积主要受地质高背景和矿山开采等因素影响,中下游地区主要受到快速城镇化、工业生产和高强度农业利用等因素的影响.针对长江经济带农田土壤重金属污染现状及管控需求,建议加强农田土壤重金属的源头防控,根据重金属污染程度、地质背景和农产品质量等进行农田土壤重金属污染的分区分级管控和分类管理,以期实现长江经济带农田土壤环境质量安全和农业绿色可持续生产. 相似文献
865.
Jinhui Liang Peng Gao Benhang Li Longfei Kang Li Feng Qi Han Yongze Liu Liqiu Zhang 《Frontiers of Environmental Science & Engineering》2022,16(12):150
866.
Chen Kang Liao Chenggang Li Ping Li Xingong Li Xianjun Zuo Yingfeng 《Journal of Polymers and the Environment》2022,30(6):2209-2221
Journal of Polymers and the Environment - Poor interfacial compatibility between wheat straw and polylactic acid (PLA) remains a problem that directly affects the overall performance of wheat... 相似文献
867.
Kim Na Kyong Kang Dong Hee Lee Wonoh Kang Hyun Wook 《Environmental Modeling and Assessment》2022,27(3):461-472
Environmental Modeling & Assessment - As the number of enclosed residential buildings increases to minimize energy consumption, research on indoor air quality is becoming more important.... 相似文献
868.
为研究黄土地层浅埋暗挖隧道松散围岩压力特征,根据既有隧道施工现场裂缝扩展情况,假定隧道开挖后的土体存在破裂区,取一半破裂区土体进行静力极限平衡分析,考虑静止土压力、侧向土压力、隧道尺寸和土层参数对半结构的影响,推导出适用于黄土地层浅埋暗挖隧道的围岩压力解析式,确定该公式下的隧道深浅埋划分界限,并结合工程实例分析隧道埋深、静止土压力系数和侧压力系数对围岩压力的影响。研究结果表明:随隧道埋深增大,围岩压力存在峰值,围岩压力曲线呈先增大后减小的趋势;围岩压力随静止土压力系数和侧压力系数的增大而减小,但静止土压力系数对围岩压力的影响较大;将新方法得到的围岩压力值分别与现场实测值和既有理论围岩压力值进行对比,计算的垂直、侧向围岩压力值均大于实测值,且新方法的计算误差相对较小。 相似文献
869.
Andrea Stojkosk Song Jing Kang Jun Liu Xudong Shuai Menglei Li Yong Zhao Liang Yang Xu 《生态毒理学报》2018,13(6):124-135
Epidemiological studies have shown that there is a link between asthma and brain damage,but toxicological studies have not fully confirmed yet,especially the effects of asthma on the brain. In this study,at first,we explore the effects of asthma on the brain through the establishment of an allergic asthma model. Then PM_(2.5),a typical outdoor air pollutant and formaldehyde,a typical indoor air pollutant were selected to be closer to the true environment and find whether there is any synergism between them. In this study,an ovalbumin( OVA)-sensitized mice asthma model was established. 30 male Balb/c mice were randomly divided into 5 groups:( 1) saline control group,( 2) OVA-sensitized group,( 3) OVA-combined with formaldehyde exposure group,( 4) OVA-combined with PM_(2.5) exposure group,( 5) Combination of OVA,formaldehyde and PM_(2.5) exposure group. The mice were inhaled with formaldehyde or/and instilled with PM_(2.5) from day 1 to 18. The mice asthma model was developed by OVA sensitization and challenge. The mice were sensitized with OVA+Al( OH)3( 5 mg OVA and 175 mg Al( OH)3 in 30 m L saline each time) or saline( 30 m L saline each time) by intraperitoneal injection on day 1,7 and 14.This was then followed by an aerosol challenge in 1% OVA( 30 min·d~(-1)) from day 19 to 25( 7 times) using an ultrasonic nebulizer. On the 26 th day,the organ coefficient of mice brain was counted,then the contents of oxidative stress of mice brain were measured,including reactive oxygen species( ROS),glutathione( GSH) and malondialdehyde( MDA),and the concentrations of NF-κB and interleukin-1β( IL-1β) were detected by using ELISA kits.Detection of interleukin-6( IL-6) was made with immunohistochemical method. Histological assay for brain was also conducted. In our results,all the OVA treated groups showed a significant increase of ROS and a significant decrease of GSH contents when compared with the control group. Except OVA-sensitized group,other OVA treated groups also showed a significant increase of MDA contents when compared with the control group,and MDA contents of OVA-sensitized group showed significant change when compared to the combined exposure group. In ROS and GSH,combined exposure showed some joint effect compared with single exposure. When OVA was applied in combination with formaldehyde and PM_(2.5),NF-κB was activated. And all the OVA treated groups showed increased levels of IL-1β and IL-6 compared with the control group. And the combined exposure showed an aggravated effect when compared with OVA-sensitized group. Histopathological observation of the hippocampus in mice brain clearly showed the difference of eosin( EO) stained neurons in the combined exposure group compared with the control group and OVA-sensitized group. The pyramidal neurons of the mice with allergic asthma exposed to formaldehyde and/or PM_(2.5) had been reduced in number,the cells were swollen and the dendrites had disappeared. Allergic asthma can cause damage to the brain through oxidative stress. Exposure to formaldehyde and PM_(2.5) will increase the damage caused by allergic asthma to the brain,which may be mediated by oxidative stress and NF-κB activation.This promotes the release of the inflammatory factors,resulting in increased inflammation. 相似文献
870.
为保证气藏型储气库安全运营,保障天然气储配调峰系统的正常运转,对气藏型储气库进行完整性管理及风险识别.明确气藏型地下储气库完整性管理的对象为地面站场系统、储气库井、地质体3大模块,以地质体完整性管理为气藏型储气库完整性管理的特点及难点,并基于管道完整性管理的理念;提出气藏型储气库完整性管理的6步循环:数据采集,单元识别... 相似文献