Total Volatile Organic Compounds in the Urban Environment of Delhi

ABSTRACT

Total volatile organic compounds (TVOCs) in the urban ambient environment of Delhi were monitored from November 1994 to June 1995 at 13 sites using an inexpensive and a manual-labor-intensive sample collection procedure in want of sophisticated equipment. The results of the study show appreciable levels of TVOCs in the ambient environment of Delhi. The amount of TVOCs in the ambient environment was found to vary between 3 and 42 ppmv and exhibited wide temporal and seasonal variations. On a diurnal cycle, TVOC levels mostly peaked at 9:00 a.m., which coincided with the peak traffic hour. TVOC buildup in the urban atmosphere has serious implications for air quality through the formation of highly toxic oxidants. The results of this preliminary study make out a strong case for a regular monitoring of TVOCs in the urban environment of Delhi.     

A Comparison of Two Techniques for the Collection and Analysis of Polynuclear Aromatic Compounds in Ambient Air

A demonstration of the GHEMFIX solidification/stabilization process was conducted under the United States Environmental Protection Agency’s (EPA) Superfund Innovative Technology Evaluation (SITE) program. The demonstration was conducted in March 1989, at the Portable Equipment Salvage Company (PESC) uncontrolled hazardous waste site in Clackamas, Oregon. Waste containing lead, copper, and polychlorinated biphenyls (PCBs) from four different areas of the site were treated. Results showed substantial reduction of leachable lead and copper between the untreated waste and treated waste utilizing the EPA Toxicity Characteristics Leaching Procedure (TCLP) test. The effectiveness of this process for immobilizing PCBs could not be determined since the raw waste did not leach PCBs at high concentrations, utilizing the TCLP test. Data from other leaching tests for lead and copper would need to be utilized as input into a site specific groundwater model to determine whether solidification/stabilization would be an acceptable remedy for the site. Physical testing results indicated durability in exposed conditions.     

Continuous Monitoring of Methane and Other Hydrocarbons In Urban Atmospheres

Continuous measurements of total hydrocarbons (and other organic substances) and of methane were made in Cincinnati and Los Angeles for three-month periods. Some of the measurements were made during episodes of photochemical air pollution. Two instruments, one for measurement of total hydrocarbons and the other for methane, were operated in parallel. Both incorporated flame ionization detectors having greater sensitivity than commercial flame ionization instruments. The flame ionization analysis for methane was made specific by use of an adsorbent carbon column preceding the analyzer to retain all organic substances except methane. Subtracting the methane concentration values from those for total hydrocarbons gave nonmethane hydrocarbon concentrations. The data showed diurnal patterns of concentrations of methane and nonmethane hydrocarbons in the atmosphere. Average hourly values for methane were strikingly similar in Los Angeles and in Cincinnati (2.6 and 2.4 ppm, respectively); those for nonmethane hydrocarbons were four times as high in Los Angeles (3.0 and 0.8 ppm, respectively). A bimodal frequency distribution pattern of the concentrations suggested that atmospheric ventilation was either good or poor, with less than a random amount of time in intermediate stages. The width of the methane frequency distribution peak was about half the width of that for nonmethane hydrocarbons, indicating a different and more constant source for the former.     

A Quantitative Review of Urban Ecosystem Service Assessments: Concepts,Models, and Implementation

Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world’s population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio-physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0504-0) contains supplementary material, which is available to authorized users.     

Distribution,Sources and Sinks of Atmospheric Halogenated Compounds

Based on two comprehensive field studies conducted in California, background concentration (parts per trillion) of N₂O (296.0 X 10³), SF₆ (0.16), CCI₂F₂ (180.8), CCI₃F (103.8), CCI₂FCCIF₂ (16.3), CCI₄ (114.2), CH₃CI (952.9), CHCI3 (23.4), CH₃I (2.4), CH3CCI3 (84.0), CCI₂CCI₂ (43.1), CHCICCI2 (14.5) and CH₃Br (—) have been reported. These trace constituents were identified using retention data on eight GC columns, their electron attachment properties, and their EC thermal response. All but CHCICCI₂ and CH₃Br were measurable 100% of the time at both sites. Cryogenic procedures for SF₆ ambient measurement were developed and successfully used. By an analysis of worldwide emissions of these trace constituents, their ambient levels, and their atmospheric lifetimes, it was possible to determine their origin (natural or anthropogenic). Our results indicate that 27% of organic chlorine contribution to the troposphere comes from fluorocarbons as opposed to a 73% contribution from the chloro-carbons. Further, the anthropogenic organic content in the troposphere was found to be about twice the natural content. Very high CHCI3 concentrations in onshore ocean waters were measured. Ambient data supporting the anthropogenic origin of CCI₄ have been presented.     

Determination of Volatile Organic Compounds in the Atmosphere Using Two Complementary Analysis Techniques

ABSTRACT

During a preliminary field campaign of volatile organic compound (VOC) measurements carried out in an urban area, two complementary analysis techniques were applied to establish the technical and scientific bases for a strategy to monitor and control VOCs and photochemical oxidants in the Autonomous Community of the Basque Country. Integrated sampling was conducted using Tenax sorbent tubes and laboratory analysis by gas chromatography, and grab sampling and in situ analysis also were conducted using a portable gas chromatograph. With the first technique, monocyclic aromatic hydrocarbons appeared as the compounds with the higher mean concentrations. The second technique allowed the systematic analysis of eight chlorinated and aromatic hydrocarbons. Results of comparing both techniques, as well as the additional information obtained with the second technique, are included.     

生活垃圾填埋场填埋气中挥发性有机物释放规律分析

于2007年2月在上海老港垃圾填埋场选取10个不同填满年限的填埋单元进行填埋气的采样分析,用色谱-质谱技术检测了填埋气中的挥发性有机物(VOCs).检测到脂肪烃、卤代脂肪烃、单环芳烃、醚和酮等5类22种化合物,其中11种为美国环境保护署优先控制污染物,甲苯、乙苯和间,对二甲苯的浓度较高.填满时间距采样时间较近(1～2年)的填埋单元检出的VOCs种类较多,脂肪烃和单环芳烃的浓度随填满时间的增加呈现较明显的衰减特征,而卤代脂肪烃、醚和酮的浓度与填满时间的相关性不显著.检出的5种化合物中,1,1,1三氯乙烷、甲苯和间,对-二甲苯的浓度均低于美国加利福尼亚州环保局推荐的健康阈值,氯乙烯和苯则超过该阈值.     

Assessment of Secondary Organic Carbon in the Southeastern United States: A Review

Abstract

Organic carbon (OC) is one of the major components of ambient PM_2.5 (particulate matter [PM] ≤ 2.5 µm in aerodynamic diameter) and a significant portion of OC is from secondary organic aerosol (SOA) formation in the southeastern United States. Various approaches (based on measurement and modeling results) are applied to estimate secondary organic carbon (SOC) and its origins in the region. SOC estimates by various methods are consistent as to clear seasonal variation (i.e., relatively higher SOC in summer) and little spatial variability (i.e., a regional characteristic of SOC). However, there are differences as to the origins of SOC. SOA organic tracer and emission-based modeling studies indicate that the biogenic origin of SOC is dominant in the Southeast, showing that biogenic-origin SOC accounts for 90% of SOC in summer and more than 70% even in other seasons. However, results from other studies suggest that the anthropogenic origin of SOC is dominant, significant amounts of anthropogenic-origin SOC, or important roles of anthropogenic pollutants for SOA formation, especially at urban areas, as strong correlations between water-soluble OC (an indicator of SOC) and anthropogenic pollutants, considerable amounts of fossil water-soluble OC, and significant contributions of fossil SOC (37–52% in summer months, 70–73% in winter months) are observed. Therefore, more studies are needed to reconcile the differences in the source attribution of SOC measurements.     

Partition of Volatile Organic Compounds in Activated Sludge and Wastewater

Abstract

The Henry’s law constant is important in the gas-liquid mass transfer process. Apparent dimensionless Henry’s law constant, or the gas-liquid partition coefficient (K’ _H), for both hydrophilic (methanol, isopropyl alcohol, and acetone) and hydrophobic (toluene and p-xylene) organic compounds in deionized (DI) water, a wastewater with a maximum total dissolved organic carbon (DOC) content of 700 mg/L, and DI water mixed with a maximum activated sludge suspended solid (SS) concentration of 40,000 mg/L were measured using the single equilibrium technique at 293 K.

Experimental results demonstrate that the K’ _H of any of the test volatile organic compounds varied among three situations. First, the K’_H of the hydrophilic compounds in mixed liquor with the maximum SS concentration was 9–21% higher than those in DI water. Second, those for toluene and p-xylene were 77% and 93% lower, respectively, in the mixed liquor with the maximum SS concentration. Third, the K’_H values of all of the test compounds in the wastewater were only 10% lower than those in DI water.

A model was developed to relate K’ _H with wastewater DOC and the SS concentration in the activated sludge using an organic carbon-water partition coefficient and activated sludge-water partition coefficient as model parameters. The model was verified and model parameters for test compounds estimated.     

Measuring Concentrations of Volatile Organic Compounds in Vinyl Flooring

ABSTRACT

The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and, consequently, affect mass transfer characteristics.

To measure solid-phase concentrations under conditions resembling those in which the material would be installed in an indoor environment, a new technique was developed for measuring VOC concentrations in vinyl flooring (VF) and similar materials. A 0.09-m² section of new VF was punched randomly to produce ~200 0.78-cm² disks. The disks were milled to a powder at -140 °C to simultaneously homogenize the material and reduce the diffusion path length without loss of VOCs. VOCs were extracted from the VF particles at room temperature by fluidized-bed desorption (FBD) and by direct thermal desorption (DTD) at elevated temperatures. The VOCs in the extraction gas from FBD and DTD were collected on sorbent tubes and analyzed by gas chromatog-raphy/mass spectrometry (GC/MS). Seven VOCs emitted by VF were quantified. Concentration measurements by FBD ranged from 5.1 |ig/g VF for n-hexadecane to 130 |Jg/g VF for phenol. Concentrations measured by DTD were higher than concentrations measured by FBD. Differences between FBD and DTD results may be explained using free-volume and dual-mobility sorption theory, but further research is necessary to more completely characterize the complex nature of a diffusant in a polymer matrix.     

Sources of Volatile Organic Compounds in a University Building

A total of 34 volatile organic compounds (VOCs) were measured in the indoor of laboratories, offices and classrooms of the Chemical Engineering Department of Hacettepe University in Ankara in 2 week-day passive sampling campaigns. The average concentrations ranged from 0.77 to 265 μg m^?3 at the different indoor sites, with the most abundant VOC found to be toluene (119.6 μg m^?3), followed by styrene (21.24 μg m^?3), 2-ethyltoluene (17.11 μg m^?3), n-hexane (10.21 μg m^?3) and benzene (9.42 μg m^?3). According to the factor analysis, the evaporation of solvents used in the laboratories was found to be the dominant source.     

机动车尾气VOCs排放特征及减排措施研究

分析了机动车尾气挥发性有机物(VOCs)的排放特征,发现尾气VOCs排放具有明显的日变化和季节变化特征。不同区域不同车型机动车尾气VOCs成分谱略有差异,轻型汽油车尾气VOCs中芳香烃和烷烃含量较高,柴油车烷烃含量较高。尾气排放受机动车保有量、行驶里程、维护保养水平、行驶速度和燃油标准、排放标准等因素影响。从优先控制汽油车、加快机动车更新、采取本地化减排措施、加强多元管理措施、提高科研水平等方面提出了针对性的减排措施。     

Regulatory Off-Gas Analysis from the Evaporation of Hanford Simulated Waste Spiked with Organic Compounds

Abstract

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, the remaining low-activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation before being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile, and pesticide compounds and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River National Laboratory. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using U.S. Environmental Protection Agency (EPA) SW-846 Methods. Volatile and light semi-volatile organic compounds (<220 °C BP, >1 mm Hg vapor pressure) in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program (licensed by OLI Systems, Inc.) evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate, and off-gas streams, with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI Environmental Simulation Program model is constrained by available literature data.     

持久性有机污染物的环境分布与生物危害

介绍了国内外持久性有机物的研究进展,分析了中国典型地区中的持久性有机污染物的分布情况,其中淮河中下游的PAHs含量较高,而大连湾检测出的DDTs和PCBs含量均高于其他地区。持久性有机污染物可以在动植物体内不断富集,据分析,有机污染物在鱼类的富集因子可高达1124．1,持久性有机污染物通过食物链的富集逐级放大,对全球生态构成潜在巨大的威胁。近年来,由于持久性有机污染物的影响,在世界各地出现了动物的死亡、甚至灭绝的现象,而且有机污染物在人体内的蓄积,会对人体产生极大的的影响。最后,就当前存在的问题,提出了对策与建议,指出了该领域的发展方向。     

Sampling and Analysis of Volatile Organic Compounds Evolved During Thermal Processing of Acrylonitrile Butadiene Styrene Composite Resins

Abstract

The evaluation of emissions of volatile organic compounds (VOCs) during processing of resins is of interest to resin manufacturers and resin processors. An accurate estimate of the VOCs emitted from resin processing has been difficult due to the wide variation in processing facilities. This study was designed to estimate the emissions in terms of mass of emitted VOC per mass of resin processed.

A collection and analysis method was developed and validated for the determination of VOCs present in the emissions of thermally processed acrylonitrile butadiene styrene (ABS) resins. Four composite resins were blended from automotive, general molding, pipe, and refrigeration grade ABS resins obtained from the manufacturers. Emission samples were collected in evacuated 6-L Summa canisters and then analyzed using gas chromatography/flame ionization detection/mass selective detection (GC/FID/MSD). Levels were determined for nine target analytes detected in canister samples, and for total VOCs detected by an inline GC/FID. The emissions evolved from the extrusion of each composite resin were expressed in terms of mass of VOCs per mass of processed resin. Styrene was the principal volatile emission from all the composite resins. VOCs analyzed from the pipe resin sample contained the highest level of styrene at 402 μg/g. An additional collection and detection method was used to determine the presence of aerosols in the emissions. This method involved collecting particulates on glass fiber filters, extracting them with solvents, and analyzing them using gas chromatography/mass spectrometry (GC/MS). No significant levels of any of the target analytes were detected on the filters.     

Effectiveness of Porous Covers for Control of Ammonia,Reduced Sulfur Compounds,Total Hydrocarbons,Selected Volatile Organic Compounds,and Odor from Hog Manure Storage Lagoons

Abstract

Anaerobic lagoons are a major source of odor at concentrated animal feeding operations. Seven different kinds of artificial (geotextile and polyethylene foam) and natural (straw and redwood) permeable lagoon covers were evaluated for their potential to reduce odorous emissions generated by anaerobic waste lagoons. A novel floating sampling raft was constructed and used to simultaneously evaluate the effectiveness of lagoon covers on an operating swine waste lagoon. The air collected from the raft was evaluated for odor, total reduced sulfur (TRS) compounds, ammonia, total hydrocarbons, dimethyldisulfide, and trimethylamine. The emission rates from the lagoon were highly variable both temporally and spatially. All of the lagoon covers substantially reduced TRS emissions and odor. Geotextile fabric and a recycled foam cover exhibited the greatest reduction in total hydrocarbon emissions; natural covers were less effective. Because of consistently low emission rates of ammonia, no statistically significant reduction of ammonia emissions were observed from any of the lagoon covers.     

An Investigation of Odors and Volatile Organic Compounds Released during Composting

ABSTRACT

The emissions of odors and volatile organic compounds produced from a commercial composting operation have been studied using a laboratory-scale composting system. The composting activity of a typical commercial compost feed was followed by monitoring the composting temperature, as well as the respiratory rate. Using a controlled aeration system, the gaseous volatiles produced were tested for odors using the "dilution-to-threshold" method, as well as gas composition, as determined by gas chromatography-mass spectrometry.

The results indicated that while there may be a reasonable correlation between the release of volatile organic compounds (VOCs) and odors, care has to be taken when trying to identify offensive odors with specific chemical species. However, the data obtained suggests that offensive odors formed during commercial composting may be due to sulfurous and nitrogenous compounds, although their concentrations in the compost gases may not be very high.

The major release of VOCs occurred during the first two weeks of composting, after which the gaseous releases fell dramatically as the composting process proceeded and temperatures started to fall.     

Long-path FTIR Measurements of Volatile Organic Compounds in an Industrial Setting

A long-path Fourier transform spectrometer was used to make measurements of volatile organic compounds in an industrial complex in New Castle, Delaware as part of the Superfund Innovative Technology Evaluation (SITE) program. These data are compared to data taken with a whole-air canister technique. To provide an effective comparison the canisters were transported along the path for a 32-min period. For each FTIR spectrum, 256 interferograms were co-added over a 4-mln period. Eight individual spectra were then co-added to obtain the comparison data.     

Evaluation of the Use of Diffusive Air Samplers for Determining Temporal and Spatial Variation of Volatile Organic Compounds in the Ambient Air of Urban Communities

Abstract

The Houston-Galveston metropolitan area has a relatively high density of point and mobile sources of air toxics, and determining and understanding the relationship between emissions and ambient air concentrations of air toxics is important for evaluating potential impacts on public health and formulating effective regulatory policies to control this impact, both in this region and elsewhere. However, conventional ambient air monitoring approaches are limited with regard to expense, siting limitations, and representative sampling necessary for adequate exposure assessment. The overall goal of this multiphase study is to evaluate the use of simple passive air samplers to determine temporal and spatial variability of the ambient air concentrations of selected volatile organic compounds (VOCs) in urban areas. Phase 1 of this study, reported here, was a field evaluation of 3M organic vapor monitors (OVMs) involving limited comparisons with commonly used active sampling methods, an assessment of sampler precision, a determination of optimal sampling duration, and an investigation of the utility of a simple modification of the commercial sampler. The results indicated that a sampling duration of 72 hr exhibited generally low bias relative to automated continuous gas chromatography measurements, good overall precision, and an acceptable number of measurements above detection limits. The modified sampler showed good correlation with the commercial sampler, with higher sampling rates, although lower than expected.     

Sources and Source Strengths of Volatile Organic Compounds in a New Office Building

This study was conducted at a newly constructed federal office building in Portland, Oregon. The primary objectives were to identify the major sources of volatile organic compounds (VOC) in the building and to measure both long-term (one year) and short-term (several day) variations in concentrations and source strengths. Samples for VOC were collected on four occasions over a period of 14 months starting with the first month of occupancy. During the final sampling period, samples were collected over four days (Friday - Monday). The samples were analyzed for individual compounds and for total VOC (TVOC). The results were expressed as specific source strengths, as well as concentrations, to facilitate comparisons of measurements made under different ventilation conditions.

The primary source of VOC in the building was identified as liquid-process photocopiers and plotters which emitted a characteristic mixture of C10-Cn isoparaffinic hydrocarbons. The specific source strength of TVOC, which was dominated by the emissions from these office machines, remained relatively constant over the course of the study. Motor vehicles in the below-ground parking garage were implicated as another major source of hydrocarbons in the building. Over the final four-day sampling period, the specific source strength of TVOC varied by about a factor of five, predominantly reflecting occupant use of office machines.