Variability in Voc Concentrations in an Urban Area of Delhi

The variability of pollutants is an important factor in determining human exposure to the chemicals. This study presents the result of investigation of variability of Volatile organic compounds (VOCs) in urban area of Delhi, capital of India. Fifteen locations, in five categories namely residential, commercial, industrial, traffic intersections and petrol pump were monitored for one year every month during peak hours in morning and evening. Measurement focused on target VOCs as defined by USEPA. Variability was divided into measurement, spatial, temporal and temporal–spatial interaction components. Temporal component along with temporal–spatial interaction were found to be the major contributors to the variability of measured VOC concentrations. Need of continuous monitoring to capture short–term peak concentration and averages is evident.     

等离子体在大气污染控制中应用进展

等离子体具有较高的温度和大量活性粒子,因此能够加速化学反应速度,彻底分解污染物.本文综述了目前常用的一些等离子体技术在大气污染控制中的应用研究进展.     

汽车运行时车内挥发性有机物污染的调查

选取汽车内的空气污染状况作为研究。结果表明：污染物主要是苯系物及烷烃;车龄影响车内空气中挥发性有机污染物的浓度;通过对车内空气进行交换能使车内空气中污染物的浓度有一定程度的降低。     

Characterization of odorous charge and photochemical reactivity of VOC emissions from a full-scale food waste treatment plant in China

Food waste treatment plants (FWTPs) are usually associated with odorous nuisance and health risks, which are partially caused by volatile organic compound (VOC) emissions. This study investigated the VOC emissions from a selected full-scale FWTP in China. The feedstock used in this plant was mainly collected from local restaurants. For a year, the FWTP was closely monitored on specific days in each season. Four major indoor treatment units of the plant, including the storage room, sorting/crushing room, hydrothermal hydrolysis unit, and aerobic fermentation unit, were chosen as the monitoring locations. The highest mean concentration of total VOC emissions was observed in the aerobic fermentation unit at 21,748.2-31,283.3 μg/m³, followed by the hydrothermal hydrolysis unit at 10,798.1-23,144.4 μg/m³. The detected VOC families included biogenic compounds (oxygenated compounds, hydrocarbons, terpenes, and organosulfur compounds) and abiogenic compounds (aromatic hydrocarbons and halocarbons). Oxygenated compounds, particularly alcohols, were the most abundant compounds in all samples. With the use of odor index analysis and principal components analysis, the hydrothermal hydrolysis and aerobic fermentation units were clearly distinguished from the pre-treatment units, as characterized by their higher contributions to odorous nuisance. Methanthiol was the dominant odorant in the hydrothermal hydrolysis unit, whereas aldehyde was the dominant odorant in the aerobic fermentation unit. Terpenes, specifically limonene, had the highest level of propylene equivalent concentration during the monitoring periods. This concentration can contribute to the increase in the atmospheric reactivity and ozone formation potential in the surrounding air.     

南京市交通干道大气环境中挥发性有机物的研究

使用Tenax管在常温下富集采样 ,研究了南京市交通干道大气环境中苯系物的污染状况和季节变化规律 ,监测过程历时 1年。同时在中山陵设点采样 ,以作背景研究。经过GC/MS联用仪分析测定 ,共检出 140多种挥发性有机物 ,其中含量较高的是苯系物。结合获得的大气中苯系物的比值以及采样点的周围环境 ,对苯系物进行源分析 ,表明苯系物主要来源于汽车尾气的排放 ,其污染程度与气候变化有关。     

室内环境中挥发性有机物释放过程的数学模型

根据组成结构,将室内环境中释放挥发性有机物(VOCs)的建筑装饰材料划分为单层干材料、单层湿材料、多层组合材料等类型,总结了这三种材料的VOCs释放特征、传输过程和数学模型研究现状,分析了模型的特点和适用范围,指出了模型研究发展的趋势,对应用中模型的选择提出了指导性建议.     

汽车车内有机挥发物(VOC)的检测

本文介绍了汽车VOC的危害以及国内外对汽车VOC的一些研究,同时对汽车整车、零部件及材料的VOC检测方法进行简单介绍,并分析了汽车内饰件产生VOC的主要来源。     

多孔材料对车用聚丙烯材料VOC问题的改善

通过考察不同类型的多孔材料对白油蒸汽的吸附能力,选择高效的多孔材料作为VOC吸附剂添加到车用聚丙烯材料中,测试经过改性后材料的TVOC含量,结果表明:多孔材料有效地吸附了聚丙烯及加工过程中产生的长链烷烃,并在测试温度下不会解吸附,从而使得材料的TVOC含量达到客户的标准要求。     

Spatial Analysis of Volatile Organic Compounds from a Community-Based Air Toxics Monitoring Network in Deer Park,Texas, USA

In the summer of 2003, ambient air concentrations of volatile organic compounds (VOCs) were measured at 12 sites within a 3-km radius in Deer Park, Texas near Houston. The purpose of the study was to assess local spatial influence of traffic and other urban sources and was part of a larger investigation of VOC spatial and temporal heterogeneity influences in selected areas of Houston. Seventy 2-h samples were collected using passive organic vapor monitors. Most measurements of 13 VOC species were greater than the method detection limits. Samplers were located at 10 residential sites, a regulatory air monitoring station, and a site located at the centroid of the census tract in which the regulatory station was located. For residential sites, sampler placement locations (e. g., covered porch vs. house eaves) had no effect on concentration with the exception of methyl tertiary-butyl ether (MTBE). Relatively high correlations (Pearson r > 0.8) were found between toluene, ethylbenzene, and o,m,p-xylenes suggesting petroleum-related influence. Chloroform was not correlated with these species or benzene (Pearson r < 0.35) suggesting a different source influence, possibly from process-related activities. As shown in other spatial studies, wind direction relative to source location had an effect on VOC concentrations.     

VOC in an urban and industrial harbor on the French North Sea coast during two contrasted meteorological situations

Two measurement campaigns of volatile organic compounds (VOC) were carried out in the industrial city of Dunkerque, using Radiello passive samplers during winter (16–23 January) and summer (6–13 June) 2007. 174 compounds were identified belonging to six chemical families. Classifying sampling sites with similar chemical profiles by hierarchical ascending classification resulted in 4 groups that reflected the influence of the main industrial and urban sources of pollution. Also, the BTEX (Benzene, Toluene, Ethylbenzene and Xylenes) quantification allowed us to map their levels of concentration. Benzene and toluene (BT) showed high concentrations in Northern Dunkerque reflecting the influence of two industrial plants. Differences among spatial distributions of the BT concentrations over contrasted meteorological conditions were also observed. An atypical ratio of T/B in the summer samples led us to investigate the BTEX origins shedding light on the contribution of pollutants transported across various zones of VOC emissions situated in Europe.