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21.
2015年干季佛山一次重空气污染过程形成机理研究 总被引:1,自引:0,他引:1
2015年12月21-23日,广东珠三角佛山地区出现了一次PM2.5重污染过程.利用佛山地区顺德、禅城、三水3个站点风廓线雷达、激光雷达和微波辐射计观测资料,结合地面气象观测数据和污染物浓度数据,分析研究了这次重污染过程的形成机理.结果表明:1形成这次污染过程的主要原因是近地层偏南风和偏北风对峙导致水平风速减小,大气水平输送能力变差;持续时间长且强度达到3℃·km-1的强逆温抑制了污染物的垂直扩散;800 m以下超过90%的高相对湿度造成气溶胶粒子吸湿增长显著.2持续时间长且比较深厚的小风层是造成这次污染过程的直接原因,小风层厚度是预报空气质量变化的较好工具.与地面风速相比,PM2.5浓度与小风层厚度的相关系数最多能提高0.36,且具有较长的预报时效.佛山地区小风层的风速阈值为3.8 m·s-1.3这次污染过程存在两种不同的污染形成机制,污染前期(21-23日中午)主要以本地污染物累积为主,污染后期(23日下午)下风向地区(三水)的污染主要是受上风向地区(顺德和禅城)的污染输送影响. 相似文献
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Source characterization of ambient fine particles at multiple sites in the Seattle area 总被引:2,自引:0,他引:2
To identify major PM2.5 (particulate matter ≤2.5 μm in aerodynamic diameter) sources with a particular emphasis on the ship engine emissions from a major port, integrated 24 h PM2.5 speciation data collected between 2000 and 2005 at five United State Environmental Protection Agency's Speciation Trends Network monitoring sites in Seattle, WA were analyzed. Seven to ten PM2.5 sources were identified through the application of positive matrix factorization (PMF). Secondary particles (12–26% for secondary nitrate; 17–20% for secondary sulfate) and gasoline vehicle emissions (13–31%) made the largest contributions to the PM2.5 mass concentrations at all of the monitoring sites except for the residential Lake Forest site, where wood smoke contributed the most PM2.5 mass (31%). Other identified sources include diesel vehicle emissions, airborne soil, residual oil combustion, sea salt, aged sea salt, metal processing, and cement kiln. Residual oil combustion sources identified at multiple monitoring sites point clearly to the Port of Seattle suggesting ship emissions as the source of oil combustion particles. In addition, the relationship between sulfate concentrations and the oil combustion emissions indicated contributions of ship emissions to the local sulfate concentrations. The analysis of spatial variability of PM2.5 sources shows that the spatial distributions of several PM2.5 sources were heterogeneous within a given air shed. 相似文献
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Changes in the dynamics of inorganic N species transformations with depth have been investigated for seven soil profiles from a nitrogen-impacted ancient grassland on a nature reserve outside York in the UK, using incubation experiments. In five of the profiles, both ammonification and nitrification are occurring below the rooting zone, probably partly in response to the low C:N ratio in the soils. This contributes to elevated nitrate concentrations found in an adjacent stream. Accumulation of ammonium during incubation in the sub-soils of these five profiles suggests a high probability of ammonium leaching down the profiles as ammonium inputs and outputs at a given depth approach equilibrium. This ammonium may also be nitrified at depth. However, in the two profiles with the most acidic surface horizons, net mineralization was negligible or negative; some initial ammonium-N and ammonium-N produced during incubation were nitrified, so the loss in ammonium-N was closely balanced by nitrate-N production. 相似文献
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Luyao Wen Chun Yang Xiaoliang Liao Yanhao Zhang Xuyang Chai Wenjun Gao Shulin Guo Yinglei Bi Suk-Ying Tsang Zhi-Feng Chen Zenghua Qi Zongwei Cai 《环境科学学报(英文版)》2022,34(5):443-452
The COVID-19 pandemic has raised awareness about various environmental issues,including PM2.5 pollution.Here,PM2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM2.5 in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM2.5 concentrations in Guangzhou.Interestingly,the trend of PM2.5 相似文献
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通过分析降水化学成分,探讨黄山景观区域降雨的微量元素化学组成特征及其来源。结果表明,降雨中微量元素含量呈现明显的季节性变化,主要受到降雨量、pH值、风向及溶解有机质等因素影响。来源分析和贡献估算结果表明,降雨中Mn、Cu、Pb、Cd、Ni、Co等元素受燃煤和交通污染排放的影响显著,贡献率均在98%以上;土壤源和人为源对Fe的贡献率分别为76. 9%、23. 1%,对Ti的贡献率为22. 8%、77. 2%; Sr主要受海洋源(28. 3%)和人为源(70. 5%)双重影响。 相似文献
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分析了我国居住建筑室内PM_(2.5)污染水平,总结了现阶段PM_(2.5)的研究方法,主要包括理论分析法、数值模拟法和实验测试法。指出室外源是室内PM_(2.5)的主要污染来源,而室内烟草烟雾、烹饪及人员活动也会严重影响室内PM_(2.5)浓度。针对目前研究中存在的问题,提出了标定典型建筑在不同影响因素下的I/O比范围、研究家具和家电的颗粒物释放状况、加强农村室内外空气颗粒物污染调查等建议。 相似文献
30.
Metabolic diversity of the heterotrophic microorganisms and potential link to pollution of the Rouge River 总被引:2,自引:0,他引:2
S.M. Tiquia 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1435-1443
The heterotrophic microbial communities of the Rouge River were tracked using Biolog Ecoplates to understand the metabolic diversity at different temporal and spatial scales, and potential link to river pollution. Site less impacted by anthrophogenic sources (site 1), showed markedly lower metabolic diversity. The only substrates that were utilized in the water samples were carbohydrates. Sites more impacted by anthrophogenic sources (sites 8 and 9) showed higher metabolic diversity. Higher functional diversity was linked to the physico-chemical and biological properties of the water samples (i.e. higher concentrations of DO, DOC, chlorophyll, and bacterial density). Biolog analysis was found to be useful in differentiating metabolic diversity between microbial communities; in determining factors that most influence the separation of communities; and in identifying which substrates were most utilized by the communities. It can also be used as an effective ecological indicator of changes in river function attributable to urbanization and pollution. 相似文献