成都市区降雨中主要低分子有机酸及来源分析

为了解成都市区降水中有机酸的化学组成特征及来源,2011年3月至9月共采降水36次,用液相色谱法检测了降水中的无机阴离子及低分子有机酸,同时测定样品的pH、电导率。用SPSS软件统计得到：有机酸的含量占总阴离子量的20．19％,对自由酸度的平均贡献值分别为31．55％。相比安顺、贵阳等地,成都市区降水中单位有机酸的酸度贡献值较小,可能是降水中的大量碱性杂质削弱了有机酸对酸度的影响。甲、乙酸占有机酸含量的93．6％,表明最主要的低分子有机酸是乙酸、甲酸。相关分析显示有机酸与所有阴离子显著相关,表明有机酸来源较复杂,多样化。进一步分析得到：甲酸与乙酸的相关系数（0．900）和偏相关系数（0．822）都很高,表明甲酸与乙酸有相似的来源或者不同来源的相似源强;甲酸与NO^3-始终显著相关表明主要来自人为活动;乙酸与nss-SO4^2-。始终显著相关表明主要来自间接源;草酸与甲酸、乙酸的偏相关系数很大程度上小于相关系数表明主要来自与甲、乙酸来源相似的前体物的光化学反应。     

我国袋式除尘行业2008年发展综述

综述了2008年我国袋式除尘行业的发展概况;分析了袋式除尘技术在水泥、钢铁与有色冶金、电力、垃圾焚烧等行业的开发应用情况;针对袋式除尘行业在发展过程中存在的主要问题提出了对策建议,并对行业的发展趋势进行了展望。     

用酸化容量法对水体发生酸化敏感性评价方法的研究

本文对我国酸雨严重地区的部分水体中的缓冲容量以及缓冲容量随酸性沉降的变化过程进行了分析研究,首次提出了用酸化容量法评价水体发生酸化的敏感性。由于该方法尽可能地考虑水体各组分之间的相互作用与联系,因而,评价结果更为科学合理     

County‐Scale Rainwater Harvesting Feasibility in the United States: Climate,Collection Area,Density, and Reuse Considerations

Roof rainwater harvesting (RWH) has the potential to augment water supplies for urban and suburban uses throughout the United States (U.S.). Studies of the performance of RWH at the building and city scales in the U.S. are available, but a countrywide overview of the potential performance of RWH at the county scale has not been done before. Three approaches were taken: (1) assess the viability of RWH in terms of the rainfall that could be captured in relation to the water demand in each county (excluding agriculture), (2) evaluate the performance of a “typical” domestic RWH system across all counties with metrics related to its ability to supply the potable and nonpotable demand, and (3) evaluate the effect of adding a 50% rainwater reuse component to the analysis. We find RWH could be a viable supplemental water source in the U.S., particularly in counties of the Pacific Northwest, Central, and Eastern regions (percent demand covered >50%). Low population density counties have the potential to meet their annual water needs with RWH, while high‐density counties could only source a small portion (~20%) of their annual demand with RWH. Typical RWH systems in counties in the Central and Eastern U.S. performed better than in Western counties. Adding a reuse component can be a key factor in making RWH attractive in many areas of the country. This work can inform future water infrastructure investment and planning in the U.S.     

Estimating Lag to Peak between Rainfall and Peak Streamflow with a Mixed‐Effects Model

We test the use of a mixed‐effects model for estimating lag to peak for small basins in Maine (drainage areas from 0.8 to 78 km²). Lag to peak is defined as the time between the center of volume of the excess rainfall during a storm event and the resulting peak streamflow. A mixed‐effects model allows for multiple observations at sites without violating model assumptions inherent in traditional ordinary least squares models, which assume each observation is independent. The mixed model includes basin drainage area and maximum 15‐min rainfall depth for individual storms as explanatory features. Based on a remove‐one‐site cross‐validation analysis, the prediction errors of this model ranged from ?42% to +73%. The mixed model substantially outperformed three published models for lag to peak and one published model for centroid lag for estimating lag to peak for small basins in Maine. Lag to peak estimates are a key input to rainfall–runoff models used to design hydraulic infrastructure. The improved accuracy and consistency with model assumptions indicates that mixed models may provide increased data utilization that could enhance models and estimates of lag to peak in other regions.     

化学沉淀法处理除氟吸附剂再生尾液的试验研究

通过试验研究了投加石灰法、投加氯化钙法、石灰-氯化钙联合法、石灰-盐酸联合法4种化学沉淀法对除氟吸附剂再生尾液的处理效果和影响因素。结果表明:静置沉淀90min后,使用投加石灰法处理pH值为12、含氟浓度为2 000mg/L的除氟吸附剂再生尾液,处理后残余氟离子浓度大于50mg/L,使用投加氯化钙法,处理后残余氟离子浓度小于20mg/L,使用石灰-氯化钙联合法和石灰-盐酸联合法,处理后残余氟离子浓度均小于10mg/L;4种方法的最佳搅拌强度为150r/min,最佳反应pH值为12左右,最佳静置时间为90min;其中,采用石灰-盐酸联合法处理pH值为12、含氟浓度为2 000mg/L的高氟再生尾液,在石灰投加量超过理论量60%(即为6.231 6g/L),加入65.4mL/L 2M的HCl时,出水可以达到国家污水排放一级标准,且pH值在7左右。     

上海宝山区酸雨特征分析

分析了连续七年(2004年-2010年)上海宝山区的降水的化学特征。从酸雨发生频率来看,2004年-2007年酸雨频率为:78.6%、75.9%、89.5%和94.6%,呈逐年加重的趋势,表明降水的酸性及酸化频率非常高,雨水酸化已非常严重。但从2008开始酸雨状况开始改善,酸雨频率开始降低,分别为:78.6%、41.1%和23.6%,同时其pH值开始高于全市平均水平;对降水中的各种阴阳离子进行数理统计分析:SO24-对降水的酸化起主要作用,但其作用在逐步减小,而NO3-和Cl-的作用呈上升的趋势;c(Cl-)/c(Na+)总体呈下降趋势,说明化工、有色金属冶金等工业生产废气中Cl2和HCl等污染物作用减少;因子分析反映了降水的来源成因机制,其结果与相关性分析一致。     

北京地区不同类型降水对气溶胶粒子的影响

利用2013~2015年大气成分与气象观测资料,分析了北京地区不同类型降水对气溶胶粒子的影响,结果表明：随着降水强度增大,PM₁₀、PM_2.5、PM₁浓度下降的时次比例、浓度下降比例均增大,PM₁₀下降幅度大于PM_2.5和PM₁;不同类型降水对气溶胶浓度影响不同,对流性降水中大气运动剧烈,对3种颗粒物都有快速而显著的清除效果;稳定性降水细分为3类,显著冷空气型的冷空气垂直下沉运动和降水湿清除可使粒子浓度缓慢下降,无显著冷空气但有颗粒物传输型的降水过程对气溶胶粒子的湿沉降效果有限,无显著冷空气无传输型气溶胶粒子吸湿增长可能导致粒子浓度不会下降;降雪或雨夹雪过程中随着降雪强度增大,气溶胶粒子浓度下降比例增大,但下降时次比例呈指数或者对数变化.雨雪相态转换的降水过程更为复杂,除了上述因素之外,还需考虑雨雪相态转变带来的水滴（雪）粒径、降水粒子对周边气流的动力拖曳作用的变化、冷空气下沉运动对流型的改变.     

荆门市城区降尘调查分析及对策

采用网格布点法对荆门市城区降尘进行普查性监测,采用类比法进行数据分析。结果表明,对荆门市降尘平均水平起主要作用的是地表扬尘,它取决于两个相互作用的因素,地表积尘量(与降雨、城区绿化地面硬化水平及城区环境卫生有关);地表扰动(风力、车流量等自然及人为活动因素)。春季,沙尘天气是荆门城区降尘的重要来源。工业污染源对个别区域影响巨大。根据调查分析提出有效防治对策。