一种计算粒子电迁移率的新模型

近几年来,粒子电迁移率引起了更多学者的注意。因为它是表征带电粒子在电场中运动的重要参数之一。在这方面,人们已作了大量的研究工作,提出了一些计算粒子电迁移率的理论和半经验模型。基于前人的研究,本文提出了一种计算粒子电迁移率的新模型,并用前人的实验结果和本研究的实验结果对此模型进行了检验。计算结果和实验数据很吻合。就某种意义上讲,此模型是对以前模型的扩展和改进,它可广泛应用于溶胶的研究和工业应用。     

灰霾天气条件下天津市环境空气中颗粒物污染特征分析

针对天津地区灰霾天气条件下环境空气中颗粒物的污染程度及变化特征进行分析。指出出现灰霾天气是污染加重的直观反映,将其发展成为一项环保指标,将对大气污染控制起到一定的积极作用。     

大气中甲磺酸粒子的来源及其对环境的影响

讨论了大气中甲磺酸粒子的来源,分析了甲磺酸粒子的自然循环及其对酸雨形成和气候变化的影响。     

Pollution characteristics of 15 gas- and particle-phase phthalates in indoor and outdoor air in Hangzhou

Phthalate esters (PAEs), typical pollutants widely used as plasticizers, are ubiquitous in various indoor and outdoor environments. PAEs exist in both gas and particle phases, posing risks to human health. In the present study, we chose four typical kinds of indoor and outdoor environments with the longest average human residence times to assess the human exposure in Hangzhou, including newly decorated residences, ordinary residences, offices and outdoor air. In order to analyze the pollution levels and characteristics of 15 gas- and particle-phase PAEs in indoor and outdoor environments, air and particulate samples were collected simultaneously. The total PAEs concentrations in the four types of environments were 25,396, 25,466.8, 15,388.8 and 3616.2?ng/m³, respectively. DEHP and DEP were the most abundant, and DMPP was at the lowest level. Distinct variations in the distributions of indoor/outdoor, gas/particle-phase and different molecular weights of PAEs were observed, showing that indoor environments were the main sources of PAEs pollution. While most PAEs tended to exsit in indoor sites and gas-phase, the high-molecular-weight chemicals tended to exist in the particle-phase and were mainly found in PM_2.5. PAEs were more likely adsorbed by small particles, especially for the indoor environments. There existed a good correlation between the particle matter concentrations and the PAEs levels. In addition, neither temperature nor humidity had obvious effects on the distributions of the PAEs concentrations.     

二氧化钛纳米微粒的制备及对染料甲基紫的降解

以钛酸丁酯为前驱体,采用溶胶-凝胶法制备纳米级二氧化钛微粒。通过二氧化钛的XRD衍射分析的实验结果,利用X射线线宽法计算二氧化钛微粒的平均粒径为22nm。以甲基紫溶液做光催化降解实验,考察各种因素对光催化降解效果的影响。结果表明：在30W紫外灯照射下,甲基紫起始浓度10mg/L,催化剂用量1．0g／L,pH为3．0,100min即可降解92％。     

张家口市沙尘天气过程气溶胶单颗粒特征研究

利用单颗粒气溶胶质谱仪对张家口市2015年春季的一次典型沙尘过程进行了监测,分析了沙尘过程对当地大气颗粒物成分的影响。结果表明,监测期间的颗粒物类型主要分为8种:矿物质(MD)、左旋葡聚糖(LEV)、元素碳(EC)、有机碳(OC)、混合碳(ECOC)、重金属(HM)、富钾(K)、其他(Other)。对比沙尘天气来临前、中、后3个时段,随着沙尘天气的来临,本地大气颗粒物成分发生较大变化,矿物质、左旋葡聚糖等成分含量升高,而有机碳、重金属等成分含量下降,其中矿物质在PM10峰值时段小时比例高达27.8%;沙尘天气期间,由于矿物质颗粒占比增加,使得总颗粒物的粒径分布向0.9μm以上的粗粒径段偏移;此外,沙尘天气期间的颗粒物各成分与二次组分的混合程度相较非沙尘天气时段的低,说明其老化程度相对较低。