双级虚拟撞击采样器应用于固定污染源PM10和PM2.5排放测量

为贯彻落实《大气污染防治行动计划》,环境保护部指导各地开展大气污染源排放清单编制工作,其中包括固定源PM_(10)和PM_(2.5)的排放清单.但目前国内尚无固定源PM_(10)和PM_(2.5)标准采样方法.本研究提出了适合我国固定源PM_(10)和PM_(2.5)测量的双级虚拟撞击采样方法,开发了相应的分级采样系统,并用该方法对各类固定源进行了现场测试.测试结果表明,所测试的煤粉炉电厂的烟囱入口PM_(2.5)质量浓度为(0.93±0.03)mg·m~(-3),PM_(10)质量浓度为(1.13±0.11)mg·m~(-3).所测试的垃圾焚烧电厂的烟囱排放口PM_(2.5)质量浓度为(3.3±0.65)mg·m~(-3),PM_(10)质量浓度为(6.9±0.86)mg·m~(-3).所测试的大型循环流化床发电厂的烟囱排放口PM_(2.5)质量浓度为(0.59±0.04)mg·m~(-3),PM_(10)质量浓度为(1.12±0.16)mg·m~(-3).所测试的钢铁转炉的烟囱排放口PM_(2.5)质量浓度为(0.15±0.04)mg·m~(-3),PM_(10)质量浓度为(0.43±0.15)mg·m~(-3).     

The effects of scale and spatial heterogeneities on diffusion in volcanic breccias and basalts: Amchitka Island, Alaska

Knowledge of the factors that influence the diffusion of contaminants, such as the diffusivity and the connected porosity, is crucial to modeling the long-term fate and transport of contaminants in subsurface systems with small or negligible advective flow, such as in fractured crystalline rock. Fractured rock is naturally heterogeneous, and hence, understanding the diffusivity of a molecule through this material (or the formation factor of the medium) becomes a complex problem, with critical concerns about the scale of laboratory measurements and about the spatial variability of these measurements relative to the scale needed for fate and transport modeling. This study employed both electrical and tracer-based laboratory methods to investigate the effects of scale and pore system connectivity on the diffusivity for volcanic matrix rock derived from the study site, a former underground nuclear test site at Amchitka Island, Alaska. The results of these investigations indicate a relatively well-connected pore system with scale effects generally limited to approximately 6 cm lengths and well-correlated to observed heterogeneous features. An important conclusion resulting from this study, however, is that there is a potential for the estimated diffusivity to be misrepresented by an order of magnitude if multiple samples or longer sample lengths are not used. Given the relatively large number of measurements resulting from these investigations, an analysis of the probability density function (PDF) of the diffusivity was possible. The PDF of the diffusivity was shown to generally follow a normal distribution for individual geologic layers. However, when all of the geologic layers are considered together, the distribution of the subsurface as a whole was shown to follow a lognormal distribution due to the order of magnitude differences amongst the layers. An understanding of these distributions is essential for future stochastic modeling efforts.     

自动喷水灭火系统喷水强度概率分布特性及其控火性能研究

喷水强度是体现自动喷水灭火系统控火能力的重要参数,具有不均匀性和不确定性.传统的喷水强度设计主要考虑喷头的流量和保护面积,没有考虑其分布特性,对系统控火性能的影响.因此本文将喷水强度分布特性引入自动喷水灭火系统的控火性能研究.以公称口径为15 mm的传统下垂型玻璃球洒水喷头的喷水强度分布实验为基础,建立了包含径向距离和喷头工作压力等参数的喷水强度分布模型,采用蒙特卡罗方法获得了喷水强度的概率分布特性.参照不同危险等级场控火所需的喷水强度参数和不同喷头开启个数下的有效控火百分比,分析了喷水强度概率分布特性对控火性能的影响.研究结果表明,喷水强度概率分布特性对控火性能有重要影响,随径向距离的增加,喷水强度出现较小值的概率增大,控火性能下降,在某些危险较大的场所不能达到控火作用.对于同一危险等级场所,控火性能随着喷头安装间距减小而增强.研究方法可为合理评估喷头适用范围、优化喷头布置提供参考.     

浅谈水质中氟化物的分析方法

经过长期的工作实践，笔者总结出能够大大提高水中氟化物测定效率及准确度的操作方法。即在使用离子选择电极法测量水中氟化物时，首先要保证试验用的去离子水的纯净度，同时确保电极清洗到260mv以上，再开始试验，最后在绘制标准曲线时保证斜率的绝对值在（58±1）之间。     

构建湘江流域生态补偿机制的探讨

本文以湘江水质和水文数据为基础,首次结合各地市社会经济发展情况,引入补偿标准系数,以湘江流域所在区域为例进行生态补偿资金测算,提出湘江流域生态补偿机制构建初步设想和存在的主要问题,以期为湘江流域水资源保护提供指导,最终实现湘江流域区域共赢。     

广州PM2.5污染特征及影响因素分析

对广州市2008—2010年PM_2.5质量浓度、影响因素数据资料进行整理统计,通过定性分析、定量计算以及对各物理量之间的相互作用过程研究,得出PM_2.5质量浓度变化特征和各影响因素之间的关系。结果表明,PM_2.5质量浓度变化呈现夏季和非夏季2种典型的季节性特征,夏季月平均值0.049 mg/m³,主要分布在0.03～0.05 mg/m³,非夏季月均值为0.063 mg/m³,分布于0.05～0.08 mg/m³之间;夏季、非夏季PM_2.5质量浓度超标率(采用美国EPA标准)分别为70.7%、77.8%,质量标准2倍、3倍以上出现的概率都表现出明显的季节性差异;PM_2.5与温度正相关,和其他因素负相关,其中与能见度相关性最大,其次是温度、风速,与降雨量相关性最差,与气压、相对湿度相关系数季节性特征显著。     

基于正交试验响应面法的烟气层概率分布计算

为计算随机参数下火灾烟气层温度和厚度的概率分布，该文提出了基于正交试验响应面的可靠度计算方法。通过正交试验表确定分析计算参数组，并借助火灾动力学分析软件计算不同参数组下烟气层的温度和厚度响应，进一步拟合出输入参数和输出参数的响应面函数，在此基础上结合验算点法计算烟气层温度和厚度的概率分布，算例分析表明该方法具有计算精度高、计算量小的特点。     

Mercury levels and trends (1993-2009) in bream (Abramis brama L.) and zebra mussels (Dreissena polymorpha) from German surface waters

Mercury concentrations have been analysed in bream (Abramis brama L.) and zebra mussels (Dreissena polymorpha) collected at 17 freshwater sites in Germany from 1993-2009 and 1994-2009, respectively, within the German Environmental Specimen programme. Mercury concentrations in bream ranged from 21 to 881 ng g⁻¹ wet weight with lowest concentrations found at the reference site Lake Belau and highest in fish from the river Elbe and its tributaries. Statistical analysis revealed site-specific differences and significant decreasing temporal trends in mercury concentrations at most of the sampling sites. The decrease in mercury levels in bream was most pronounced in fish from the river Elbe and its tributary Mulde, while in fish from the river Saale mercury levels increased. Temporal trends seem to level off in recent years. Mercury concentrations in zebra mussels were much lower than those in bream according to their lower trophic position and varied by one order of magnitude from 4.1 to 42 ng g⁻¹ wet weight (33-336 ng g⁻¹ dry weight). For zebra mussels, trend analyses were performed for seven sampling sites at the rivers Saar and Elbe of which three showed significant downward trends. There was a significant correlation of the geometric mean concentrations in bream and zebra mussel over the entire study period at each sampling site (Pearson’s correlation coefficient = 0.892, p = 0.00002). A comparison of the concentrations in bream with the environmental quality standard (EQS) of 20 ng g⁻¹ wet weight set for mercury in biota by the EU showed that not a single result was in compliance with this limit value, not even those from the reference site. Current mercury levels in bream from German rivers exceed the EQS by a factor 4.5-20. Thus, piscivorous top predators are still at risk of secondary poisoning by mercury exposure via the food chain. It was suggested focusing monitoring of mercury in forage fish (trophic level 3 or 4) for compliance checking with the EQS for biota and considering the age dependency of mercury concentrations in fish in the monitoring strategy.     

不同模糊评价方法在水环境质量评价中的应用比较

近年来,运用模糊评价方法对水质和水体营养化程度进行评价逐渐受到重视。目前,对模糊评价方法的研究多集中在实测数据标准化、权重的确定和模糊模式识别模型研究几个方面。以滇池历年营养物质数据为实测数据,通过对几种实测数据标准化方法、权重确定方法和模糊模式识别方法的组合应用,获得水环境质量模糊评价最优组合方法。结果表明,在评价方法中,实测数据标准化方法采用线性内插法,权重的确定采用超标倍数法,模糊模式识别模型采用广义海明距离和加权海明距离法,即采用超标倍数法的广义海明距离和加权海明距离法能够更真实反映水环境质量的实际情况。     

有害物质环境测试组合舱的研制及性能评价

研制了一种新型有害物质环境测试组合舱,该测试舱由舱体系（内舱和外舱）、恒温恒湿空气处理系统、空气循环装置和信号控制与处理软件组成。该测试舱具有可分别使用内舱和外舱对样品进行测试的特点,并采用美国FLUNT公司开发的air pack软件包对内舱和外舱的气流进行模拟与计算,并划分出内舱的层流区域,同时也对舱体系的性能进行了测试与评价。结果表明,有害物质环境测试组合舱的温湿度的相对标准偏差分别为0.04℃和0.7%,混合性达到90.7%。因此,该有害物质环境测试组合舱对温湿度控制精准,气流稳定,混合性能良好,能为室内空气污染研究提供条件稳定的室内仿真环境。