WorldWideScience

Sample records for voc source reduction

  1. Implementation of VOC source reduction practices in a manufactured house and in school classrooms

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, A.T.; Apte, M.G.; Shendell, D.G.; Beal, D.; McIlvaine, J.E.R.

    2002-01-01

    Detailed studies of a new manufactured house and four new industrialized relocatable school classrooms were conducted to determine the emission sources of formaldehyde and other VOCs and to identify and implement source reduction practices. Procedures were developed to generate VOC emission factors that allowed reasonably accurate predictions of indoor air VOC concentrations. Based on the identified sources of formaldehyde and other aldehydes, practices were developed to reduce the concentrations of these compounds in new house construction. An alternate ceiling panel reduced formaldehyde concentrations in the classrooms. Overall, the classrooms had relatively low VOC concentrations.

  2. Source Apportionment of VOCs in Edmonton, Alberta

    Science.gov (United States)

    McCarthy, M. C.; Brown, S. G.; Aklilu, Y.; Lyder, D. A.

    2012-12-01

    Regional emissions at Edmonton, Alberta, are complex, containing emissions from (1) transportation sources, such as cars, trucks, buses, and rail; (2) industrial sources, such as petroleum refining, light manufacturing, and fugitive emissions from holding tanks or petroleum terminals; and (3) miscellaneous sources, such as biogenic emissions and natural gas use and processing. From 2003 to 2009, whole air samples were collected at two sites in Edmonton and analyzed for over 77 volatile organic compounds (VOCs). VOCs were sampled in the downtown area (Central) and the industrial area on the eastern side of the city (East). Concentrations of most VOCs were highest at the East site. The positive matrix factorization (PMF) receptor model was used to apportion ambient concentration measurements of VOCs into eleven factors, which were associated with emissions source categories. Factors of VOCs identified in the final eleven-factor solution include transportation sources (both gasoline and diesel vehicles), industrial sources, a biogenic source, and a natural-gas-related source. Transportation sources accounted for more mass at the Central site than at the East site; this was expected because Central is in a core urban area where transportation emissions are concentrated. Transportation sources accounted for nearly half of the VOC mass at the Central site, but only 6% of the mass at the East site. Encouragingly, mass from transportation sources has declined by about 4% a year in this area; this trend is similar to the decline found throughout the United States, and is likely due to fleet turnover as older, more highly polluting cars are replaced with newer, cleaner cars. In contrast, industrial sources accounted for ten times more VOC mass at the East site than at the Central site and were responsible for most of the total VOC mass observed at the East site. Of the six industrial factors identified at the East site, four were linked to petrochemical industry production

  3. Locating industrial VOC sources with aircraft observations

    Energy Technology Data Exchange (ETDEWEB)

    Toscano, P., E-mail: p.toscano@ibimet.cnr.it [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Gioli, B. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Dugheri, S. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Salvini, A. [Department of Organic Chemistry, University of Florence, Via della Lastruccia 13, 50019 Sesto Fiorentino, Florence (Italy); Matese, A. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Bonacchi, A. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Zaldei, A. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Cupelli, V. [Careggi Hospital-University of Florence, Occupational Health Division, Largo Palagi 1, 50100 Florence (Italy); Miglietta, F. [Institute for Biometeorology (IBIMET - CNR), Via G. Caproni 8, 50145 Firenze (Italy); Fondazione Edmund Mach, Via Mach 1, San Michele all' Adige, Trento (Italy)

    2011-05-15

    Observation and characterization of environmental pollution, focussing on Volatile Organic Compounds (VOCs), in a high-risk industrial area, are particularly important in order to provide indications on a safe level of exposure, indicate eventual priorities and advise on policy interventions. The aim of this study is to use the Solid Phase Micro Extraction (SPME) method to measure VOCs, directly coupled with atmospheric measurements taken on a small aircraft environmental platform, to evaluate and locate the presence of VOC emission sources in the Marghera industrial area. Lab analysis of collected SPME fibres and subsequent analysis of mass spectrum and chromatograms in Scan Mode allowed the detection of a wide range of VOCs. The combination of this information during the monitoring campaign allowed a model (Gaussian Plume) to be implemented that estimates the localization of emission sources on the ground. - Highlights: > Flight plan aimed at sampling industrial area at various altitudes and locations. > SPME sampling strategy was based on plume detection by means of CO{sub 2}. > Concentrations obtained were lower than the limit values or below the detection limit. > Scan mode highlighted presence of {gamma}-butyrolactone (GBL) compound. > Gaussian dispersion modelling was used to estimate GBL source location and strength. - An integrated strategy based on atmospheric aircraft observations and dispersion modelling was developed, aimed at estimating spatial location and strength of VOC point source emissions in industrial areas.

  4. Source apportionment of ambient VOCs in Delhi City.

    Science.gov (United States)

    Srivastava, Anjali; Sengupta, B; Dutta, S A

    2005-05-01

    Source apportionment using chemical mass balance (CMB) model was carried using a data set of 360 four hourly samples collected at 15 locations of five categories namely residential, commercial, industrial, traffic intersections and petrol pumps during August 2001-July 2002 in Delhi. The results indicate that emissions from diesel internal combustion engines dominate in Delhi. Vehicular exhaust and evaporative emissions also contribute significantly to VOCs in ambient air. Emission of VOCs associated with sewage sludge was also found to contribute to VOCs in Delhi's air. This points to the fact that open defecation and leaking sewage manholes are a problem in all categories of locations.

  5. Source apportionment of ambient VOCs in Delhi City

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Anjali [National Environmental Engineering Research Institute, 89/B, Dr.A.B.Road, Worli, Mumbai-400 018 (India); Sengupta, B.; Dutta, S.A. [Central Pollution Control Board, Parivesh Bhawan, East Arjun Nagar, Delhi-110032 (India)

    2005-05-01

    Source apportionment using chemical mass balance (CMB) model was carried using a data set of 360 four hourly samples collected at 15 locations of five categories namely residential, commercial, industrial, traffic intersections and petrol pumps during August 2001-July 2002 in Delhi. The results indicate that emissions from diesel internal combustion engines dominate in Delhi. Vehicular exhaust and evaporative emissions also contribute significantly to VOCs in ambient air. Emission of VOCs associated with sewage sludge was also found to contribute to VOCs in Delhi's air. This points to the fact that open defecation and leaking sewage manholes are a problem in all categories of locations. (author)

  6. Chlorinated volatile organic compounds (Cl-VOCs) in environment - sources, potential human health impacts, and current remediation technologies.

    Science.gov (United States)

    Huang, Binbin; Lei, Chao; Wei, Chaohai; Zeng, Guangming

    2014-10-01

    Chlorinated volatile organic compounds (Cl-VOCs), including polychloromethanes, polychloroethanes and polychloroethylenes, are widely used as solvents, degreasing agents and a variety of commercial products. These compounds belong to a group of ubiquitous contaminants that can be found in contaminated soil, air and any kind of fluvial mediums such as groundwater, rivers and lakes. This review presents a summary of the research concerning the production levels and sources of Cl-VOCs, their potential impacts on human health as well as state-of-the-art remediation technologies. Important sources of Cl-VOCs principally include the emissions from industrial processes, the consumption of Cl-VOC-containing products, the disinfection process, as well as improper storage and disposal methods. Human exposure to Cl-VOCs can occur through different routes, including ingestion, inhalation and dermal contact. The toxicological impacts of these compounds have been carefully assessed, and the results demonstrate the potential associations of cancer incidence with exposure to Cl-VOCs. Most Cl-VOCs thus have been listed as priority pollutants by the Ministry of Environmental Protection (MEP) of China, Environmental Protection Agency of the U.S. (U.S. EPA) and European Commission (EC), and are under close monitor and strict control. Yet, more efforts will be put into the epidemiological studies for the risk of human exposure to Cl-VOCs and the exposure level measurements in contaminated sites in the future. State-of-the-art remediation technologies for Cl-VOCs employ non-destructive methods and destructive methods (e.g. thermal incineration, phytoremediation, biodegradation, advanced oxidation processes (AOPs) and reductive dechlorination), whose advantages, drawbacks and future developments are thoroughly discussed in the later sections. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Status and Needs Research for On-line Monitoring of VOCs Emissions from Stationary Sources

    Science.gov (United States)

    Zhou, Gang; Wang, Qiang; Zhong, Qi; Zhao, Jinbao; Yang, Kai

    2018-01-01

    Based on atmospheric volatile organic compounds (VOCs) pollution control requirements during the twelfth-five year plan and the current status of monitoring and management at home and abroad, instrumental architecture and technical characteristics of continuous emission monitoring systems (CEMS) for VOCs emission from stationary sources are investigated and researched. Technological development needs of VOCs emission on-line monitoring techniques for stationary sources in china are proposed from the system sampling pretreatment technology and analytical measurement techniques.

  8. Volatile organic compounds (VOCs) source profiles of on-road vehicle emissions in China.

    Science.gov (United States)

    Hong-Li, Wang; Sheng-Ao, Jing; Sheng-Rong, Lou; Qing-Yao, Hu; Li, Li; Shi-Kang, Tao; Cheng, Huang; Li-Ping, Qiao; Chang-Hong, Chen

    2017-12-31

    Volatile Organic Compounds (VOCs) source profiles of on-road vehicles were widely studied as their critical roles in VOCs source apportionment and abatement measures in megacities. Studies of VOCs source profiles from on-road motor vehicles from 2001 to 2016 were summarized in this study, with a focus on the comparisons among different studies and the potential impact of different factors. Generally, non-methane hydrocarbons dominated the source profile of on-road vehicle emissions. Carbonyls, potential important components of vehicle emission, were seldom considered in VOCs emissions of vehicles in the past and should be paid more attention to in further study. VOCs source profiles showed some variations among different studies, and 6 factors were extracted and studied due to their impact to VOCs source profile of on-road vehicles. Vehicle types, being dependent on engine types, and fuel types were two dominant factors impacting VOCs sources profiles of vehicles. In comparison, impacts of ignitions, driving conditions and accumulated mileage were mainly due to their influence on the combustion efficiency. An opening and interactive database of VOCs from vehicle emissions was critically essential in future, and mechanisms of sharing and inputting relative research results should be formed to encourage researchers join the database establishment. Correspondingly, detailed quality assurance and quality control procedures were also very important, which included the information of test vehicles and test methods as detailed as possible. Based on the community above, a better uncertainty analysis could be carried out for the VOCs emissions profiles, which was critically important to understand the VOCs emission characteristics of the vehicle emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Sources of long-lived atmospheric VOCs at the rural boreal forest site, SMEAR II

    Science.gov (United States)

    Patokoski, J.; Ruuskanen, T. M.; Kajos, M. K.; Taipale, R.; Rantala, P.; Aalto, J.; Ryyppö, T.; Nieminen, T.; Hakola, H.; Rinne, J.

    2015-12-01

    In this study a long-term volatile organic compound (VOCs) concentration data set, measured at the SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations) boreal forest site in Hyytiälä, Finland during the years 2006-2011, was analyzed in order to identify source areas and profiles of the observed VOCs. VOC mixing ratios were measured using proton transfer reaction mass spectrometry. Four-day HYSPLIT 4 (Hybrid Single Particle Lagrangian Integrated Trajectory) backward trajectories and the Unmix 6.0 receptor model were used for source area and source composition analysis. Two major forest fire events in Russia took place during the measurement period. The effect of these fires was clearly visible in the trajectory analysis, lending confidence to the method employed with this data set. Elevated volume mixing ratios (VMRs) of non-biogenic VOCs related to forest fires, e.g. acetonitrile and aromatic VOCs, were observed. Ten major source areas for long-lived VOCs (methanol, acetonitrile, acetaldehyde, acetone, benzene, and toluene) observed at the SMEAR II site were identified. The main source areas for all the targeted VOCs were western Russia, northern Poland, Kaliningrad, and the Baltic countries. Industrial areas in northern continental Europe were also found to be source areas for certain VOCs. Both trajectory and receptor analysis showed that air masses from northern Fennoscandia were less polluted with respect to both the VOCs studied and other trace gases (CO, SO2 and NOx), compared to areas of eastern and western continental Europe, western Russia, and southern Fennoscandia.

  10. Estimation of sources and factors affecting indoor VOC levels using basic numerical methods

    Directory of Open Access Journals (Sweden)

    Sibel Mentese

    2016-11-01

    Full Text Available Volatile Organic Compounds (VOCs are a concern due to their adverse health effects and extensive usage. Levels of indoor VOCs were measured in six homes located in three different towns in Çanakkale, Turkey. Monthly indoor VOC samples were collected by passive sampling throughout a year. The highest levels of total volatile organic compounds (TVOC, benzene, toluene, and xylenes occurred in industrial, rural, and urban sites in a descending order. VOC levels were categorized as average values annually, during the heating period, and non-heating period. Several building/environmental factors together with occupants’ habits were scored to obtain a basic indoor air pollution index (IAPi for the homes. Bivariate regression analysis was applied to find the associations between the pollutant levels and home scores. IAPi scores were found to be correlated with average indoor VOC levels. In particular, very strong associations were found for occupants’ habits. Furthermore, observed indoor VOC levels were categorized by using self-organizing map (SOM and two simple scoring approaches, rounded average and maximum value methods, to classify the indoor environments based on their VOC compositions (IAPvoc. Three classes were used for both IAPi and IAPvoc approaches, namely “good”, “moderate”, and “bad”. There is an urgent need for indexing studies to determine the potential sources and/or factors affecting observed VOCs. This study gives a basic but good start for further studies.

  11. [Anthropogenic VOC emission inventory and contribution from industrial sources in Ningbo].

    Science.gov (United States)

    Li, Xuan; Wang, Xue-Song; Liu, Zhong; Wu, Liang; Weng, Yan-Bo; Hu, Jie

    2014-07-01

    Ningbo is an important industrial city in eastern China and is also the economic center in the south wing of the Yangtze River Delta (YRD). Recently, the VOC emissions from the local industrial activities and its effects on both the regional air quality and people's health were getting more and more attention. The anthropogenic VOC emission inventory of Ningbo in 2010 was established with collecting comprehensive activity data of anthropogenic sources. Furthermore, the industrial sectors were studied and the significant industries were identified with their contribution quantified. The result shows that the amount of anthropogenic VOC emission in Ningbo in 2010 is 176 kt. Industry, transportation and residential source are the most important VOC anthropogenic sources in Ningbo, which accounted for 62.0%, 17.2% and 15.5% respectively. Synthetic materials manufacturing and refined petroleum products manufacturing are the most important VOC emitting industries, which contributed 18.6% and 13.1% of the total VOC amount respectively, signifying the influence of these two industries to the VOC emissions in Ningbo.

  12. VOC Source and Inflow Characterization during the Deep Convective Cloud and Chemistry (DC3) experiment

    Science.gov (United States)

    Blake, N. J.; Hartt, G.; Barletta, B.; Simpson, I. J.; Schroeder, J.; Hung, Y.; Marrero, J.; Gartner, A.; Hirsch, C.; Meinardi, S.; Blake, D. R.; Zhang, Y.; Apel, E. C.; Hornbrook, R. S.; Campos, T. L.; Emmons, L. K.

    2013-12-01

    More than 50 volatile organic compounds (VOCs) were measured during the Deep Convective Clouds and Chemistry Project (DC3) field campaign, which was based out of Salina, KS May 10 - June 30, 2012. DC3 investigated the impact of deep, mid-latitude continental convective clouds on upper tropospheric composition and chemistry. The UCI Whole Air Sampler (WAS) measured VOCs on board the NASA DC-8 aircraft and the NCAR Trace Organic Gas Analyzer (TOGA) measured VOCs on board the NSF GV. Coordinated flights between the two aircraft produced a rich dataset with which to characterize the inflow and outflow of convective events. While probing storm inflow, numerous natural and anthropogenic sources were encountered, including oil and gas wells in Colorado, Texas, and Oklahoma, biomass burning, biogenic VOC emissions, and other anthropogenic sources (urban, feedlots, etc). The significant and widespread influence of oil and gas activities dominated VOC alkane distributions during DC3, in both inflow and outflow, effectively illustrating the connection between emission and fast vertical transport of VOCs into the free troposphere. We present a mass balance analysis of a flight over TX and OK, which allowed us to estimate oil and gas emissions in that region. The results from this analysis will be compared to previous work in the same area, as well as to emissions from other oil and gas regions and to model simulations from the Community Atmosphere Model with Chemistry (CAM-chem).

  13. Mapping methane sources and emissions over California from direct airborne flux and VOC source tracer measurements

    Science.gov (United States)

    Guha, A.; Misztal, P. K.; Peischl, J.; Karl, T.; Jonsson, H. H.; Woods, R. K.; Ryerson, T. B.; Goldstein, A. H.

    2013-12-01

    Quantifying the contributions of methane (CH4) emissions from anthropogenic sources in the Central Valley of California is important for validation of the statewide greenhouse gas (GHG) inventory and subsequent AB32 law implementation. The state GHG inventory is largely based on activity data and emission factor based estimates. The 'bottom-up' emission factors for CH4 have large uncertainties and there is a lack of adequate 'top-down' measurements to characterize emission rates. Emissions from non-CO2 GHG sources display spatial heterogeneity and temporal variability, and are thus, often, poorly characterized. The Central Valley of California is an agricultural and industry intensive region with large concentration of dairies and livestock operations, active oil and gas fields and refining operations, as well as rice cultivation all of which are known CH4 sources. In order to gain a better perspective of the spatial distribution of major CH4 sources in California, airborne measurements were conducted aboard a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of low-altitude and mixed layer airborne CH4 and CO2 measurements alongside coincident VOC measurements. Transects during eight unique flights covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. We report direct quantification of CH4 fluxes using real-time airborne Eddy Covariance measurements. CH4 and CO2 were measured at 1-Hz data rate using an instrument based on Cavity Ring Down Spectroscopy (CRDS) along with specific VOCs (like isoprene, methanol, acetone etc.) measured at 10-Hz using Proton Transfer Reaction Mass Spectrometer - Eddy Covariance (PTRMS-EC) flux system. Spatially resolved eddy covariance

  14. Model-basedapproachtoaccountforthevariationofprimaryVOCemissions over time in the identification of indoor VOC sources

    DEFF Research Database (Denmark)

    Han, KwangHoon; Zhang, Jensen S.; Wargocki, Pawel

    2012-01-01

    , considering thevariation in long-term emission rates of individual VOCs. Results showed that the proposed approach could predict theemission signatures of individual building materials at a later time (9-month) with less than 6% difference variance, and hence indicated the potential ofthe source...

  15. Spatial/Temporal Variations and Source Apportionment of VOCs Monitored at Community Scale in an Urban Area

    Science.gov (United States)

    Yu, Chang Ho; Zhu, Xianlei; Fan, Zhi-hua

    2014-01-01

    This study aimed to characterize spatial/temporal variations of ambient volatile organic compounds (VOCs) using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile) sites in Paterson and one background site in Chester, NJ (located ∼58 km southwest of Paterson). Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene) were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (pindustrial emissions (16%), mobile+stationery sources (12%), small shop emissions (11%), and others (22%). Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in Paterson. The study demonstrated the community-scale monitoring approach can capture spatial variation of VOCs in an urban community with mixed VOC sources. It also provided robust data to identify major sources of concern in the community. PMID:24755686

  16. VOC source-receptor relationships in Houston during TexAQS-II

    Science.gov (United States)

    Leuchner, Michael; Rappenglück, Bernhard

    2010-10-01

    During the TRAMP field campaign in August-September 2006, C 2-C 10 volatile organic compounds (VOCs) were measured continuously and online at the urban Moody Tower (MT) site. This dataset was compared to corresponding VOC data sets obtained at six sites located in the highly industrialized Houston Ship Channel area (HSC). Receptor modeling was performed by positive matrix factorization (PMF) at all sites. Conditional probability functions (CPF) were used to determine the origin of the polluted air masses in the Houston area. A subdivision into daytime and nighttime was carried out to discriminate photochemical influences. Eight main source categories of industrial, mobile, and biogenic emissions were identified at the urban receptor site, seven and six, respectively, at the different HSC sites. At MT natural gas/crude oil contributed most to the VOC mass (27.4%), followed by liquefied petroleum gas (16.7%), vehicular exhaust (15.3%), fuel evaporation (14.3%), and aromatics (13.4%). Also petrochemical sources from ethylene (4.7%) and propylene (3.6%) play an important role. A minor fraction of the VOC mass can be attributed to biogenic sources mainly from isoprene (4.4%). Based on PMF analyses of different wind sectors, the total VOC mass was estimated to be twofold at MT with wind directions from HSC compared to air from a typical urban sector, for petrochemical compounds more than threefold. Despite the strong impact of air masses influenced by industrial sources at HSC, still about a third of the total mass contributions at MT can be apportioned to other sources, mainly motor vehicles and aromatic solvents. The investigation of diurnal variation in combination with wind directional frequencies revealed the greatest HSC impact at the urban site during the morning, and the least during the evening.

  17. Seasonal variability and source apportionment of volatile organic compounds (VOCs in the Paris megacity (France

    Directory of Open Access Journals (Sweden)

    A. Baudic

    2016-09-01

    Full Text Available Within the framework of air quality studies at the megacity scale, highly time-resolved volatile organic compound (C2–C8 measurements were performed in downtown Paris (urban background sites from January to November 2010. This unique dataset included non-methane hydrocarbons (NMHCs and aromatic/oxygenated species (OVOCs measured by a GC-FID (gas chromatograph with a flame ionization detector and a PTR-MS (proton transfer reaction – mass spectrometer, respectively. This study presents the seasonal variability of atmospheric VOCs being monitored in the French megacity and their various associated emission sources. Clear seasonal and diurnal patterns differed from one VOC to another as the result of their different origins and the influence of environmental parameters (solar radiation, temperature. Source apportionment (SA was comprehensively conducted using a multivariate mathematical receptor modeling. The United States Environmental Protection Agency's positive matrix factorization tool (US EPA, PMF was used to apportion and quantify ambient VOC concentrations into six different sources. The modeled source profiles were identified from near-field observations (measurements from three distinct emission sources: inside a highway tunnel, at a fireplace and from a domestic gas flue, hence with a specific focus on road traffic, wood-burning activities and natural gas emissions and hydrocarbon profiles reported in the literature. The reconstructed VOC sources were cross validated using independent tracers such as inorganic gases (NO, NO2, CO, black carbon (BC and meteorological data (temperature. The largest contributors to the predicted VOC concentrations were traffic-related activities (including motor vehicle exhaust, 15 % of the total mass on the annual average, and evaporative sources, 10 %, with the remaining emissions from natural gas and background (23 %, solvent use (20 %, wood-burning (18 % and a biogenic source (15 %. An

  18. Seasonal variability and source apportionment of volatile organic compounds (VOCs) in the Paris megacity (France)

    Science.gov (United States)

    Baudic, Alexia; Gros, Valérie; Sauvage, Stéphane; Locoge, Nadine; Sanchez, Olivier; Sarda-Estève, Roland; Kalogridis, Cerise; Petit, Jean-Eudes; Bonnaire, Nicolas; Baisnée, Dominique; Favez, Olivier; Albinet, Alexandre; Sciare, Jean; Bonsang, Bernard

    2016-09-01

    Within the framework of air quality studies at the megacity scale, highly time-resolved volatile organic compound (C2-C8) measurements were performed in downtown Paris (urban background sites) from January to November 2010. This unique dataset included non-methane hydrocarbons (NMHCs) and aromatic/oxygenated species (OVOCs) measured by a GC-FID (gas chromatograph with a flame ionization detector) and a PTR-MS (proton transfer reaction - mass spectrometer), respectively. This study presents the seasonal variability of atmospheric VOCs being monitored in the French megacity and their various associated emission sources. Clear seasonal and diurnal patterns differed from one VOC to another as the result of their different origins and the influence of environmental parameters (solar radiation, temperature). Source apportionment (SA) was comprehensively conducted using a multivariate mathematical receptor modeling. The United States Environmental Protection Agency's positive matrix factorization tool (US EPA, PMF) was used to apportion and quantify ambient VOC concentrations into six different sources. The modeled source profiles were identified from near-field observations (measurements from three distinct emission sources: inside a highway tunnel, at a fireplace and from a domestic gas flue, hence with a specific focus on road traffic, wood-burning activities and natural gas emissions) and hydrocarbon profiles reported in the literature. The reconstructed VOC sources were cross validated using independent tracers such as inorganic gases (NO, NO2, CO), black carbon (BC) and meteorological data (temperature). The largest contributors to the predicted VOC concentrations were traffic-related activities (including motor vehicle exhaust, 15 % of the total mass on the annual average, and evaporative sources, 10 %), with the remaining emissions from natural gas and background (23 %), solvent use (20 %), wood-burning (18 %) and a biogenic source (15 %). An important finding of

  19. Application of CSIA to distinguish between vapor intrusion and indoor sources of VOCs.

    Science.gov (United States)

    McHugh, Thomas; Kuder, Tomasz; Fiorenza, Stephanie; Gorder, Kyle; Dettenmaier, Erik; Philp, Paul

    2011-07-15

    At buildings with potential for vapor intrusion of volatile organic chemicals (VOCs) from the subsurface, the ability to accurately distinguish between vapor intrusion and indoor sources of VOCs is needed to support accurate and efficient vapor intrusion investigations. We have developed a method for application of compound-specific stable isotope analysis (CSIA) for this purpose that uses an adsorbent sampler to obtain sufficient sample mass from the air for analysis. Application of this method to five residences near Hill Air Force Base in Utah indicates that subsurface and indoor sources of tricholorethene and tetrachloroethene often exhibit distinct carbon and chlorine isotope ratios. The differences in isotope ratios between indoor and subsurface sources can be used to identify the source of these chemicals when they are present in indoor air.

  20. [Source apportionment of VOCs in the northern suburb of Nanjing in summer].

    Science.gov (United States)

    Yang, Hui; Zhu, Bin; Gao, Jin-Hui; Li, Yong-Yu; Xia, Li

    2013-12-01

    Hourly concentrations of ambient volatile organic compounds (VOCs) were sampled in August 2012 in the northern suburb of Nanjing. Emissions of VOCs were analyzed by using PMF (positive matrix factorization) and CPF (conditional probability function). The hourly average mixing ratio of the TVOCs in summer was (33.84 +/- 27.77) x 10(-9), with a bimodal diurnal variation trend. 49.3% of the TVOCs were alkanes, 24.4% were alkenes, 18.5% were aromatics and 7.81% were acetylene. Five sources were identified as summer major contributors to ambient VOCs concentrations by PMF. 33.1% of the total VOCs was attributed to vehicle related emissions, 25.8% to fuel evaporation, 23.2% to industrial emissions, 8.1% to solvent evaporation and 9.7% to plant emissions. For alkanes, vehicle emissions, industrial emissions, fuel and solvent evaporation accounted for 23.7%, 35.3%, 31.3% and 2%, respectively. For alkenes, fuel evaporation accounted for 41.1% , industrial emissions for 18.4%, and vehicle emission for 24.3%. Vehicle emission was the major contributor to aromatics, accounting for 49.2%, followed by solvent evaporation, which accounted for 30.8%.

  1. Evaluating the effectiveness of joint emission control policies on the reduction of ambient VOCs: Implications from observation during the 2014 APEC summit in suburban Beijing

    Science.gov (United States)

    Li, Kun; Li, Junling; Wang, Weigang; Tong, Shengrui; Liggio, John; Ge, Maofa

    2017-09-01

    Ambient volatile organic compounds (VOCs) at a suburban Beijing site were on-line detected using proton transfer reaction-mass spectrometry (PTR-MS) during autumn of 2014, near the location of the Asia-Pacific Economic Cooperation (APEC) summit. During the APEC summit, the Chinese government enacted strict emission control policies. It was found that VOC concentrations only slightly decreased during the first emission control period (EC I), when control policies were performed in Beijing and 5 cities along the Tai-hang Mountains. However, most of the VOCs (10 out of 12 non-biogenic species) significantly decreased (more than 40%) during the second emission control period (EC II), when control policies were carried out in 16 cities including Beijing, Tianjin, 8 cities of Hebei province and 6 cities of Shandong province. Also the ratio of toluene and benzene decreased during EC II, likely because the emission control policies changed the proportions of different anthropogenic sources. Using the positive matrix factorization (PMF) source apportionment method, five factors are analyzed: (1) vehicle + fuel, (2) solvent, (3) biomass burning, (4) secondary, and (5) background + long-lived. Among them, vehicle + fuel, solvent and biomass burning contribute most of the VOCs concentrations (60%-80%) during the polluted periods and are affected most by emission control policies. During EC II, the reductions of vehicle + fuel, solvent, biomass burning and secondary species were all no less than 50%. Overall, when emission control policies were carried out in many North China Plain (NCP) cities (i.e. EC II), the VOC concentrations of suburban Beijing markedly decreased. This indicates the cross-regional joint-control policies have a large influence on reductions of organic gas species. The findings of this study have vital implications for helping formulate effective emission control policies in China and other countries.

  2. Oil and Natural Gas Industry Sources Covered by the 2012 New Source Performance Standards (NSPS) for Volatile Organic Compounds (VOCs) and the 2016 NSPS for Methane and VOCs, by Site

    Science.gov (United States)

    This is a 2016 table that looks at oil and natural gas industry site types and lists the applicable rules for the 2012 and 2016 new source performance standards (NSPS) and Volatile Organic Compounds (VOC) rules.

  3. Response surface modeling-based source contribution analysis and VOC emission control policy assessment in a typical ozone-polluted urban Shunde, China.

    Science.gov (United States)

    You, Zhiqiang; Zhu, Yun; Jang, Carey; Wang, Shuxiao; Gao, Jian; Lin, Che-Jen; Li, Minhui; Zhu, Zhenghua; Wei, Hao; Yang, Wenwei

    2017-01-01

    To develop a sound ozone (O3) pollution control strategy, it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O3. Using the "Shunde" city as a pilot summer case study, we apply an innovative response surface modeling (RSM) methodology based on the Community Multi-Scale Air Quality (CMAQ) modeling simulations to identify the O3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O3 impacts of volatile organic compound (VOC) control strategy. Our results show that Shunde is a typical VOC-limited urban O3 polluted city. The "Jiangmen" city, as the main upper wind area during July 2014, its VOCs and nitrogen oxides (NOx) emissions make up the largest contribution (9.06%). On the contrary, the contribution from local (Shunde) emission is lowest (6.35%) among the seven neighbor regions. The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde. The results of dynamic source contribution analysis further show that the local NOx control could slightly increase the ground O3 under low (10.00%) and medium (40.00%) reduction ratios, while it could start to turn positive to decrease ground O3 under the high NOx abatement ratio (75.00%). The real-time assessment of O3 impacts from VOCs control strategies in Pearl River Delta (PRD) shows that the joint regional VOCs emission control policy will effectively reduce the ground O3 concentration in Shunde. Copyright © 2016. Published by Elsevier B.V.

  4. Source apportionment of ambient volatile organic compounds (VOCs)and their characteristics in Chengdu, southwest of China

    Science.gov (United States)

    Deng, Yuanyuan; Xie, Shaodong; Li, Jing; Li, Yaqi

    2017-04-01

    Chengdu, located in the largest basin region in the world, suffers from increasing ground-level ozone and aerosol pollutions. Volatile organic compounds (VOCs) are one of the prominent precursors of ground-level ozone and aerosols. Ambient VOCs were measured continuously using an online gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) with a time resolution of 1 hour from 28 August 2016 to 7 October 2016 at Pixian in Chengdu. 99 measurements of VOCs were conducted including 28 alkanes, 11 alkenes, 16 aromatics, 13 oxygenated VOCs (OVOCs) and 29 halocarbons, acetylene, and acetonitrile. Based on the hourly average data, positive matrix factorization (PMF) was used to better understand the emission sources of VOCs in Chengdu. The average mixing ratios of alkanes, alkenes, aromatics, OVOCs, halocarbons, acetylene, and acetonitrile were respectively 14.49 ppbv, 4.92 ppbv, 5.14 ppbv, 9.74 ppbv, 7.77 ppbv, 3.56 ppbv, and 0.43 ppbv. Six sources were extracted by using PMF model. Liquefied petroleum gas, background and petrochemical industries contributed 28%, 19%, 18% to the total ambient VOCs, respectively. Biogenic emission (14%), Gasoline vehicles (13%), Solvent use (8%) were also identified as major sources of ambient VOCs at Pixian.

  5. Spatial/temporal variations and source apportionment of VOCs monitored at community scale in an urban area.

    Directory of Open Access Journals (Sweden)

    Chang Ho Yu

    Full Text Available This study aimed to characterize spatial/temporal variations of ambient volatile organic compounds (VOCs using a community-scale monitoring approach and identify the main sources of concern in Paterson, NJ, an urban area with mixed sources of VOCs. VOC samples were simultaneously collected from three local source-dominated (i.e., commercial, industrial, and mobile sites in Paterson and one background site in Chester, NJ (located ∼58 km southwest of Paterson. Samples were collected using the EPA TO-15 method from midnight to midnight, one in every sixth day over one year. Among the 60 analyzed VOCs, ten VOCs (acetylene, benzene, dichloromethane, ethylbenzene, methyl ethyl ketone, styrene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene were selected to examine their spatial/temporal variations. All of the 10 VOCs in Paterson were significantly higher than the background site (p<0.01. Ethylbenzene, m,p-xylene, o-xylene, and p-dichlorobenzene measured at the commercial site were significantly higher than the industrial/mobile sites (p<0.01. Seven VOCs (acetylene, benzene, dichloromethane, methyl ethyl ketone, styrene, toluene, and p-dichlorobenzene were significantly different by season (p<0.05, that is, higher in cold seasons than in warm seasons. In addition, dichloromethane, methyl ethyl ketone, and toluene were significantly higher on weekdays than weekend days (p<0.05. These results are consistent with literature data, indicating the impact of anthropogenic VOC sources on air pollution in Paterson. Positive Matrix Factorization (PMF analysis was applied for 24-hour integrated VOC measurements in Paterson over one year and identified six contributing factors, including motor vehicle exhausts (20%, solvents uses (19%, industrial emissions (16%, mobile+stationery sources (12%, small shop emissions (11%, and others (22%. Additional locational analysis confirmed the identified sources were well matched with point sources located upwind in

  6. Emissions of Volatile Organic Compounds (VOCs) from Animal Husbandry: Chemical Compositions, Separation of Sources and Animal Types

    Science.gov (United States)

    Yuan, B.; Coggon, M.; Koss, A.; Warneke, C.; Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; De Gouw, J. A.

    2016-12-01

    Concentrated animal feeding operations (CAFOs) are important sources of volatile organic compounds (VOCs) in the atmosphere. We used a hydronium ion time-of-flight chemical ionization mass spectrometer (H3O+ ToF-CIMS) to measure VOC emissions from CAFOs in the Northern Front Range of Colorado during an aircraft campaign (SONGNEX) for regional contributions and from a mobile laboratory sampling for chemical characterizations of individual animal feedlots. The main VOCs emitted from CAFOs include carboxylic acids, alcohols, carbonyls, phenolic species, sulfur- and nitrogen-containing species. Alcohols and carboxylic acids dominate VOC concentrations. Sulfur-containing and phenolic species become more important in terms of odor activity values and NO3 reactivity, respectively. The high time-resolution mobile measurements allow the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the increase of ethanol concentrations were primarily associated with feed storage and handling. We apply a multivariate regression analysis using NH3 and ethanol as tracers to attribute the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls and carboxylic acids. Phenolic species and nitrogen-containing species are predominantly associated with animals and their waste. VOC ratios can be potentially used as indicators for the separation of emissions from dairy and beef cattle from the regional aircraft measurements.

  7. Using Positive Matrix Factorization to Investigate Sources of VOCs in Bakersfield

    Science.gov (United States)

    Scola, S. E.; Schroeder, J.; Blake, D. R.

    2015-12-01

    Bakersfield, California consistently ranks among the nation's top three most polluted cities in terms of both ozone and particulate pollution. An important step in developing control strategies for the mitigation of ozone is determining the contribution of various emission sources of ozone precursors, such as volatile organic compounds (VOCs), in Bakersfield. During the SARP 2015 campaign, whole air samples were collected over Bakersfield and other Central Valley emission sources - including oil and natural gas sites and agricultural areas - and analyzed by gas chromatography. To estimate the influence of oil and natural gas sources on air in Bakersfield, the ratio of i-pentane to n-pentane was used. Use of this ratio demonstrated mixed urban and oil and natural gas influences in the Bakersfield samples. To better identify and quantify the contributions of oil and natural gas fields as well as other regional emission sources on Bakersfield air quality, positive matrix factorization (PMF) was applied to whole air samples taken within the planetary boundary layer in the Central Valley. PMF generated three interpretable factors: an urban source, an oil and natural gas source, and an agricultural/biogenically-influenced source. The contribution of each of the three sources on the mixing ratios of C1-C7 alkanes and isoprene was calculated. Of the non-methane VOCs in Bakersfield, it was determined that 45% originated from the oil and natural gas sites, 34% from the agriculture/biogenically-influenced sources, and 21% from urban areas. Furthermore, it was observed that there was a better agreement between PMF results and propane to ethyne ratios than with i-pentane to n-pentane ratios.

  8. National survey of MTBE and other VOCs in community drinking-water sources

    Science.gov (United States)

    Clawges, Rick M.; Rowe, Barbara L.; Zogorski, John S.

    2001-01-01

    Methyl tert-butyl ether (MTBE) is a volatile organic compound (VOC) that is added to gasoline either seasonally or year round in many parts of the United States to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The chemical properties and widespread use of MTBE can result in contamination of private and public drinking-water sources. MTBE contamination is a concern in drinking water because of the compound's low taste and odor threshold and potential human-health effects.

  9. Emissions of volatile organic compounds (VOCs) from concentrated animal feeding operations (CAFOs): chemical compositions and separation of sources

    Science.gov (United States)

    Yuan, Bin; Coggon, Matthew M.; Koss, Abigail R.; Warneke, Carsten; Eilerman, Scott; Peischl, Jeff; Aikin, Kenneth C.; Ryerson, Thomas B.; de Gouw, Joost A.

    2017-04-01

    Concentrated animal feeding operations (CAFOs) emit a large number of volatile organic compounds (VOCs) to the atmosphere. In this study, we conducted mobile laboratory measurements of VOCs, methane (CH4) and ammonia (NH3) downwind of dairy cattle, beef cattle, sheep and chicken CAFO facilities in northeastern Colorado using a hydronium ion time-of-flight chemical-ionization mass spectrometer (H3O+ ToF-CIMS), which can detect numerous VOCs. Regional measurements of CAFO emissions in northeastern Colorado were also performed using the NOAA WP-3D aircraft during the Shale Oil and Natural Gas Nexus (SONGNEX) campaign. Alcohols and carboxylic acids dominate VOC concentrations and the reactivity of the VOCs with hydroxyl (OH) radicals. Sulfur-containing and phenolic species provide the largest contributions to the odor activity values and the nitrate radical (NO3) reactivity of VOC emissions, respectively. VOC compositions determined from mobile laboratory and aircraft measurements generally agree well with each other. The high time-resolution mobile measurements allow for the separation of the sources of VOCs from different parts of the operations occurring within the facilities. We show that the emissions of ethanol are primarily associated with feed storage and handling. Based on mobile laboratory measurements, we apply a multivariate regression analysis using NH3 and ethanol as tracers to determine the relative importance of animal-related emissions (animal exhalation and waste) and feed-related emissions (feed storage and handling) for different VOC species. Feed storage and handling contribute significantly to emissions of alcohols, carbonyls, carboxylic acids and sulfur-containing species. Emissions of phenolic species and nitrogen-containing species are predominantly associated with animals and their waste.

  10. The indoor volatile organic compound (VOC) characteristics and source identification in a new university campus in Tianjin, China.

    Science.gov (United States)

    Kang, Jian; Liu, Junjie; Pei, Jingjing

    2017-06-01

    This study investigates the volatile organic compounds (VOCs) constituents and concentration levels on a new university campus, where all of the buildings including classrooms and student dormitories were newly built and decorated within 1 year. Investigated indoor environments include dormitories, classrooms, and the library. About 30 dormitory buildings with different furniture loading ratios were measured. The characteristics of the indoor VOCs species are analyzed and possible sources are identified. The VOCs were analyzed with gas chromatography-mass spectroscopy (GC-MS). It was found that the average total VOC (TVOC) concentration can reach 2.44 mg/m3. Alkenes were the most abundant VOCs in dormitory rooms, contributing up to 86.5% of the total VOCs concentration. The concentration of α-pinene is the highest among the alkenes. Unlike the dormitory rooms, there is almost no room with TVOC concentration above 0.6 mg/m3 in classroom and library buildings. Formaldehyde concentration in the dormitory rooms increased about 23.7% after the installation of furniture, and the highest level reached 0.068 mg/m3. Ammonia released from the building antifreeze material results in an average indoor concentration of 0.28 mg/m3, which is 100% over the threshold and should be seriously considered. Further experiments were conducted to analyze the source of the α-pinene and some alkanes in dormitory rooms. The results showed that the α-pinene mainly comes from the bed boards, while the wardrobes are the main sources of alkanes. The contribution of the pinewood bed boards to the α-pinene and TVOC concentration can reach up to above 90%. The same type rooms were sampled 1 year later and the decay rate of α-pinene is quite high, close to 100%, so that it almost cannot be detected in the sampled rooms. Analysis of indoor volatile organic compounds (VOCs) in newly built campus buildings in China identified the specific constituents of indoor VOCs contaminants exposed to Chinese

  11. Industrial sector-based volatile organic compound (VOC) source profiles measured in manufacturing facilities in the Pearl River Delta, China.

    Science.gov (United States)

    Zheng, Junyu; Yu, Yufan; Mo, Ziwei; Zhang, Zhou; Wang, Xinming; Yin, Shasha; Peng, Kang; Yang, Yang; Feng, Xiaoqiong; Cai, Huihua

    2013-07-01

    Industrial sector-based VOC source profiles are reported for the Pearl River Delta (PRD) region, China, based source samples (stack emissions and fugitive emissions) analyzed from sources operating under normal conditions. The industrial sectors considered are printing (letterpress, offset and gravure printing processes), wood furniture coating, shoemaking, paint manufacturing and metal surface coating. More than 250 VOC species were detected following US EPA methods TO-14 and TO-15. The results indicated that benzene and toluene were the major species associated with letterpress printing, while ethyl acetate and isopropyl alcohol were the most abundant compounds of other two printing processes. Acetone and 2-butanone were the major species observed in the shoemaking sector. The source profile patterns were found to be similar for the paint manufacturing, wood furniture coating, and metal surface coating sectors, with aromatics being the most abundant group and oxygenated VOCs (OVOCs) as the second largest contributor in the profiles. While OVOCs were one of the most significant VOC groups detected in these five industrial sectors in the PRD region, they have not been reported in most other source profile studies. Such comparisons with other studies show that there are differences in source profiles for different regions or countries, indicating the importance of developing local source profiles. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  12. Using the chemical mass balance model to estimate VOC source contributions in newly built timber frame houses: a case study.

    Science.gov (United States)

    Plaisance, Herve; Mocho, Pierre; Sauvat, Nicolas; Vignau-Laulhere, Jane; Raulin, Katarzyna; Desauziers, Valerie

    2017-11-01

    Basing on the material emission data obtained in a test chamber, chemical mass balance (CMB) was used to assess the source apportionment of volatile organic compound (VOC) concentrations in three newly built timber frame houses. CMB has been proven to be able to discriminate the source contributions for two contrasted environmental conditions (with and without ventilation). The shutdown of the ventilation system caused an increase in the VOC concentrations due to the increased contribution of indoor surface materials like the door material and furniture explaining together over 65% of total VOCs. While the increase in formaldehyde concentration is mainly due to furniture (contribution of 70%), the increase in α-pinene concentration is almost exclusively attributable to the emission of door material (up to 84%). The apportionment of VOC source contributions appears as highly dependent on the position of source materials in the building (surface materials or internal materials) and the ventilation conditions explaining that the concentrations of compounds after the shutdown of ventilation system do not increase in equivalent proportion. Knowledge of indoor sources and its contributions in real conditions may help in the selection of materials and in the improvement of construction operations to reduce the indoor air pollution.

  13. CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

    Science.gov (United States)

    The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

  14. Consideration of the Change of Material Emission Signatures due to Longterm Emissions for Enhancing VOC Source Identification

    DEFF Research Database (Denmark)

    Han, K. H.; Zhang, J. S.; Knudsen, Henrik Nellemose

    2011-01-01

    The objectives of this study were to characterize the changes of VOC material emission profiles over time and develop a method to account for such changes in order to enhance a source identification technique that is based on the measurements of mixed air samples and the emission signatures...... were tested individually for nine months and later in combination to obtain actual mixture emissions. VOC emissions from each material were measured in a 50liter smallscale chamber. Chamber air was sampled by PTRMS over a 28day period to determine their emission rate decay characteristics as well...

  15. Reduction of VOC emissions by a membrane-based gas absorption process.

    Science.gov (United States)

    Li, Rui; Xu, Jun; Wang, Lianjun; Li, Jiansheng; Sun, Xiuyun

    2009-01-01

    A membrane-based gas absorption (MGA) process was evaluated for the removal of volatile organic compounds (VOCs) based on C6H6/N2 mixture. The absorption of C6H6 from a C6H6/N2 mixture was investigated using a hydrophobic polypropylene hollow fiber membrane contactor and the aqueous solution of N-formyl morpholine (NFM) as absorbent. The effects of various factors on the overall mass transfer coefficient was investigated. The experimental results showed that the removal efficiency of C6H6 could reach 99.5% in present studied system. A mathematical model based on resistance-in-series concept was presented to predict the value of overall mass transfer coefficient. The average error between the predicted and experimental values is 7.9%. In addition, conventional packed columns for VOCs removal was also evaluated for comparison.

  16. Review of unsaturated-zone transport and attenuation of volatile organic compound (VOC) plumes leached from shallow source zones

    Science.gov (United States)

    Rivett, Michael O.; Wealthall, Gary P.; Dearden, Rachel A.; McAlary, Todd A.

    2011-04-01

    Reliable prediction of the unsaturated zone transport and attenuation of dissolved-phase VOC (volatile organic compound) plumes leached from shallow source zones is a complex, multi-process, environmental problem. It is an important problem as sources, which include solid-waste landfills, aqueous-phase liquid discharge lagoons and NAPL releases partially penetrating the unsaturated zone, may persist for decades. Natural attenuation processes operating in the unsaturated zone that, uniquely for VOCs includes volatilisation, may, however, serve to protect underlying groundwater and potentially reduce the need for expensive remedial actions. Review of the literature indicates that only a few studies have focused upon the overall leached VOC source and plume scenario as a whole. These are mostly modelling studies that often involve high strength, non-aqueous phase liquid (NAPL) sources for which density-induced and diffusive vapour transport is significant. Occasional dissolved-phase aromatic hydrocarbon controlled infiltration field studies also exist. Despite this lack of focus on the overall problem, a wide range of process-based unsaturated zone — VOC research has been conducted that may be collated to build good conceptual model understanding of the scenario, particularly for the much studied aromatic hydrocarbons and chlorinated aliphatic hydrocarbons (CAHs). In general, the former group is likely to be attenuated in the unsaturated zone due to their ready aerobic biodegradation, albeit with rate variability across the literature, whereas the fate of the latter is far less likely to be dominated by a single mechanism and dependent upon the relative importance of the various attenuation processes within individual site — VOC scenarios. Analytical and numerical modelling tools permit effective process representation of the whole scenario, albeit with potential for inclusion of additional processes — e.g., multi-mechanistic sorption phase partitioning, and

  17. VOCs emission rate estimate for complicated industrial area source using an inverse-dispersion calculation method: A case study on a petroleum refinery in Northern China.

    Science.gov (United States)

    Wei, Wei; Lv, Zhaofeng; Yang, Gan; Cheng, Shuiyuan; Li, Yue; Wang, Litao

    2016-11-01

    This study aimed to apply an inverse-dispersion calculation method (IDM) to estimate the emission rate of volatile organic compounds (VOCs) for the complicated industrial area sources, through a case study on a petroleum refinery in Northern China. The IDM was composed of on-site monitoring of ambient VOCs concentrations and meteorological parameters around the source, calculation of the relationship coefficient γ between the source's emission rate and the ambient VOCs concentration by the ISC3 model, and estimation of the actual VOCs emission rate from the source. Targeting the studied refinery, 10 tests and 8 tests were respectively conducted in March and in June of 2014. The monitoring showed large differences in VOCs concentrations between background and downwind receptors, reaching 59.7 ppbv in March and 248.6 ppbv in June, on average. The VOCs increases at receptors mainly consisted of ethane (3.1%-22.6%), propane (3.8%-11.3%), isobutane (8.5%-10.2%), n-butane (9.9%-13.2%), isopentane (6.1%-12.9%), n-pentane (5.1%-9.7%), propylene (6.1-11.1%) and 1-butylene (1.6%-5.4%). The chemical composition of the VOCs increases in this field monitoring was similar to that of VOCs emissions from China's refineries reported, which revealed that the ambient VOCs increases were predominantly contributed by this refinery. So, we used the ISC3 model to create the relationship coefficient γ for each receptor of each test. In result, the monthly VOCs emissions from this refinery were calculated to be 183.5 ± 89.0 ton in March and 538.3 ± 281.0 ton in June. The estimate in June was greatly higher than in March, chiefly because the higher environmental temperature in summer produced more VOCs emissions from evaporation and fugitive process of the refinery. Finally, the VOCs emission factors (g VOCs/kg crude oil refined) of 0.73 ± 0.34 (in March) and 2.15 ± 1.12 (in June) were deduced for this refinery, being in the same order with previous direct

  18. Natural vs. Anthropogenic: Combined Measurements of Methane and Volatile Organic Compounds (VOCs) for Investigating Sources of Methane Emissions

    Science.gov (United States)

    Zannoni, N.; Assan, S.; Gros, V.; Laville, P.; Loubet, B.; Ciuraru, R.; Baisnee, D.; Bonsang, B.; Sarda Esteve, R.; Chuppin, G.; Truong, F.; Lafouge, F.; Vogel, F. R.

    2016-12-01

    Methane is the second globally most abundant anthropogenic greenhouse gas, whose emissions contribute more than 1/3 of today's additional anthropogenic warming. Methane is emitted from the production and transport of coal, oil and natural gas, as well as from livestock and agricultural practices as well as from natural sources such as e.g. wetlands, freshwaters and wild fauna. Volatile organic compounds constitute less than 0.1% of the total atmospheric composition; however, their emissions and further atmospheric photo-oxidation reactions produce ozone and secondary organic aerosols which have adverse effects on climate and air quality. We measured the concentration of methane and volatile organic compounds (VOCs) over a winter wheat (Triticum aestivum) cropland located in the North-West of Europe during June 2016. The measurements site was located nearby a farm and a methanizer bioreactor, therefore was affected by contrasted sources of emissions: agricultural practices, enteric digestion of livestock, animal manures as well as possible leakages from the biogas unit. Here, measurements of methane, its isotopic composition, and VOCs concentrations are combined to investigate the fingerprint of these sources. Specifically, VOCs, as alkanes which are co-emitted by natural gas, and other compounds as ammonia and NOx will help to unravel the different sources contributions.

  19. Simultaneous VOC reduction and moisture leveling in veneer with microwave energy during early stage of drying

    Energy Technology Data Exchange (ETDEWEB)

    Abedi, Jalal [Department of Chemical & amp; Petroleum Engineering, niversity of Calgary, 2500 University Dr., NW, Calgary, Alberta (Canada T2N N4); Banerjee, Sujit [School of Chemical & amp; Biomedical Engineering, eorgia Institute of Technology, Atlanta, GA (United States)

    2007-01-15

    The main objective of this investigation was to quantitatively determine the ability of a microwave energy to level the moisture content of veneers using infrared thermography system. It is believed that the proper use of RF drying may reduce the emissions of volatile organic compounds (VOCs) from the sheets of plywood veneer as they are dried. Currently, the RF units are used after the drying, for the purpose of distributing the moisture that may be left in the pieces of veneer in some places (wet spot). Microwaving green veneer briefly under low headspace conditions evens out the moisture distribution for both softwood and hardwood, with the effect being more pronounced for softwood. The drying rate is unaffected. If successful, this could lead to significant cost savings for plywood producers. (author)

  20. Assessment of the reduction methods used to develop chemical schemes: building of a new chemical scheme for VOC oxidation suited to three-dimensional multiscale HOx-NOx-VOC chemistry simulations

    Directory of Open Access Journals (Sweden)

    S. Szopa

    2005-01-01

    Full Text Available The objective of this work was to develop and assess an automatic procedure to generate reduced chemical schemes for the atmospheric photooxidation of volatile organic carbon (VOC compounds. The procedure is based on (i the development of a tool for writing the fully explicit schemes for VOC oxidation (see companion paper Aumont et al., 2005, (ii the application of several commonly used reduction methods to the fully explicit scheme, and (iii the assessment of resulting errors based on direct comparison between the reduced and full schemes. The reference scheme included seventy emitted VOCs chosen to be representative of both anthropogenic and biogenic emissions, and their atmospheric degradation chemistry required more than two million reactions among 350000 species. Three methods were applied to reduce the size of the reference chemical scheme: (i use of operators, based on the redundancy of the reaction sequences involved in the VOC oxidation, (ii grouping of primary species having similar reactivities into surrogate species and (iii grouping of some secondary products into surrogate species. The number of species in the final reduced scheme is 147, this being small enough for practical inclusion in current three-dimensional models. Comparisons between the fully explicit and reduced schemes, carried out with a box model for several typical tropospheric conditions, showed that the reduced chemical scheme accurately predicts ozone concentrations and some other aspects of oxidant chemistry for both polluted and clean tropospheric conditions.

  1. Review of unsaturated-zone transport and attenuation of volatile organic compound (VOC) plumes leached from shallow source zones.

    Science.gov (United States)

    Rivett, Michael O; Wealthall, Gary P; Dearden, Rachel A; McAlary, Todd A

    2011-04-25

    Reliable prediction of the unsaturated zone transport and attenuation of dissolved-phase VOC (volatile organic compound) plumes leached from shallow source zones is a complex, multi-process, environmental problem. It is an important problem as sources, which include solid-waste landfills, aqueous-phase liquid discharge lagoons and NAPL releases partially penetrating the unsaturated zone, may persist for decades. Natural attenuation processes operating in the unsaturated zone that, uniquely for VOCs includes volatilisation, may, however, serve to protect underlying groundwater and potentially reduce the need for expensive remedial actions. Review of the literature indicates that only a few studies have focused upon the overall leached VOC source and plume scenario as a whole. These are mostly modelling studies that often involve high strength, non-aqueous phase liquid (NAPL) sources for which density-induced and diffusive vapour transport is significant. Occasional dissolved-phase aromatic hydrocarbon controlled infiltration field studies also exist. Despite this lack of focus on the overall problem, a wide range of process-based unsaturated zone - VOC research has been conducted that may be collated to build good conceptual model understanding of the scenario, particularly for the much studied aromatic hydrocarbons and chlorinated aliphatic hydrocarbons (CAHs). In general, the former group is likely to be attenuated in the unsaturated zone due to their ready aerobic biodegradation, albeit with rate variability across the literature, whereas the fate of the latter is far less likely to be dominated by a single mechanism and dependent upon the relative importance of the various attenuation processes within individual site - VOC scenarios. Analytical and numerical modelling tools permit effective process representation of the whole scenario, albeit with potential for inclusion of additional processes - e.g., multi-mechanistic sorption phase partitioning, and provide

  2. Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions. Part I: study area description, data set acquisition and qualitative data analysis of the data set.

    Science.gov (United States)

    Badol, Caroline; Locoge, Nadine; Léonardis, Thierry; Galloo, Jean-Claude

    2008-01-25

    The global objective of this two part study was (1) to conduct VOC measurements in order to further understand VOC behaviour in an urban area influenced by industrial emissions and (2) to evaluate the role of these specific sources relative to urban sources. In this first paper a thorough descriptive and qualitative analysis is performed. A second article will be devoted to the quantitative analysis using Chemical Mass Balance (CMB) modelling. In the Dunkerque (France) area most industrial sources are situated in the north and the west of the receptor site whereas urban and traffic sources are located in the south and the east. A data set constituted of nearly 330,000 VOC data has been developed from the hourly measurements of 53 VOCs for 1 year from September 2002 to August 2003. It also contains meteorological parameters such as temperature, wind direction and wind speed. Using different graphical methods, the influence of the different sources on the ambient VOC concentrations has been highlighted at different time scales. In this work, the analysis of daily time series for the 53 VOCs shows the influence of traffic exhaust emissions because of the increases at traffic rush hours. Besides, the seasonal evolution of the VOC/acetylene ratio points out the influence of evaporative sources on ambient VOC concentration. Concerning other point sources, the variations of measured VOC concentrations for different wind directions and scatter plots of VOC hourly concentrations highlight the influence of some industrial sources.

  3. Waterpipe smoke: source of toxic and carcinogenic VOCs, phenols and heavy metals?

    Science.gov (United States)

    Schubert, Jens; Müller, Frederic D; Schmidt, Roman; Luch, Andreas; Schulz, Thomas G

    2015-11-01

    The use of the waterpipe, a traditional aid for the consumption of tobacco, has spread worldwide and is steadily increasing especially among the youth. On the other hand, there is a lack of knowledge regarding the composition of mainstream waterpipe smoke and the toxicological risks associated with this kind of smoking habit. Using a standardized machine smoking protocol, mainstream waterpipe smoke was generated and further analyzed for twelve volatile organic compounds (VOCs) and eight phenolic compounds by applying gas chromatography-mass spectrometry and reverse-phase high-performance liquid chromatography-fluorescence detection, respectively. Additionally, seventeen elements were analyzed in waterpipe tobacco and charcoal prior to and after smoking, applying inductively coupled plasma-mass spectrometry to assess the maximum exposure of these elements. For the first time ever, we have been able to show that waterpipe mainstream smoke contains high levels of the human carcinogen benzene. Compared with cigarette smoke yields, the levels were 6.2-fold higher, thus representing a significant health hazard for the waterpipe smoker. Furthermore, we found that waterpipe mainstream smoke contains considerable amounts of catechol, hydroquinone and phenol, each of which causing some health concern at least. The analysis of waterpipe tobacco and charcoal revealed that both matrices contained considerable amounts of the toxic elements nickel, cadmium, lead and chromium. Altogether, the data on VOCs, phenols and elements presented in this study clearly point to the health hazards associated with the consumption of tobacco using waterpipes.

  4. The reduction of formaldehyde and VOCs emission from wood-based flooring by green adhesive using cashew nut shell liquid (CNSL).

    Science.gov (United States)

    Kim, Sumin

    2010-10-15

    To discuss the reduction of formaldehyde and volatile organic compound (VOC) emissions from engineered flooring, cashew nut shell liquid (CNSL)-formaldehyde (CF) resin and CF/PVAc resin were applied for the maple face of the veneer bonding on plywood. The CF resin was used to replace urea-formaldehyde (UF) resin in the formaldehyde-based resin system in order to reduce formaldehyde and VOC emissions from the adhesives used between the plywoods and fancy veneers. For the CF/PVAc resins, 5, 10, 20 or 30% of PVAc was added to the CF resin. The CF/PVAc resins showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The standard formaldehyde emission test and a VOC analyzer were used to determine the formaldehyde and VOC emissions, respectively, from the engineered floorings. The CF resin and CF/PVAc resin systems with UV coating satisfied the E(1) and E(0) grades of the Korean Standard. TVOC emission was slightly increased by the PVAc addition. 2010 Elsevier B.V. All rights reserved.

  5. Simultaneous assessments of occurrence, ecological, human health, and organoleptic hazards for 77 VOCs in typical drinking water sources from 5 major river basins, China.

    Science.gov (United States)

    Chen, Xichao; Luo, Qian; Wang, Donghong; Gao, Jijun; Wei, Zi; Wang, Zijian; Zhou, Huaidong; Mazumder, Asit

    2015-11-01

    Owing to the growing public awareness on the safety and aesthetics in water sources, more attention has been given to the adverse effects of volatile organic compounds (VOCs) on aquatic organisms and human beings. In this study, 77 target VOCs (including 54 common VOCs, 13 carbonyl compounds, and 10 taste and odor compounds) were detected in typical drinking water sources from 5 major river basins (the Yangtze, the Huaihe, the Yellow, the Haihe and the Liaohe River basins) and their occurrences were characterized. The ecological, human health, and olfactory assessments were performed to assess the major hazards in source water. The investigation showed that there existed potential ecological risks (1.30 × 10 ≤ RQtotals ≤ 8.99 × 10) but little human health risks (6.84 × 10(-7) ≤ RQtotals ≤ 4.24 × 10(-4)) by VOCs, while that odor problems occurred extensively. The priority contaminants in drinking water sources of China were also listed based on the present assessment criteria. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Field Methods to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs

    Science.gov (United States)

    2012-03-01

    Stable isotopes do not undergo radioactive decay – tritium is not a stable isotope p e- Hydrogen, 1H n p e- Deuterium , 2H, D n p ne - Tritium, 3H, T...C12 C12 Kinetic Effect: Biodegradation causes enrichment in PCE containing 13C Biodegradatio n of PCE: 12C – Cl bond easier to break than 13C – Cl...n e R a t i o Subsurface source NOT enriched in heavy isotopes: CSIA not likely to distinguish between indoor and subsurface sources. SS Carbon

  7. Wind tunnels vs. flux chambers: Area source emission measurements and the necessity for VOC and odour correction factors

    Science.gov (United States)

    Wind tunnels and flux chambers have been used to measure fluxes of volatile organic compounds (VOC), odour, and ammonia (NH3) with little regard to air velocity or sweep air flow rates. As a result, flux measurements have been highly variable and scientists have been in disagreement as to the better...

  8. Development of a methodology examining the behaviours of VOCs source apportionment with micro-meteorology analysis in an urban and industrial area.

    Science.gov (United States)

    Xiang, Yang; Delbarre, Hervé; Sauvage, Stéphane; Léonardis, Thierry; Fourmentin, Marc; Augustin, Patrick; Locoge, Nadine

    2012-03-01

    During summer 2009, online measurements of 25 Volatile Organic Compounds (VOCs) from C6 to C10 as well as micro-meteorological parameters were simultaneously performed in the industrial city of Dunkerque. With the obtained data set, we developed a methodology to examine how the contributions of different source categories depend on atmospheric turbulences, and the results provided identification of emission modes. Eight factors were resolved by using Positive Matrix Factorization model and three of them were associated with mixed sources. The observed behaviours of contributions with turbulences lead to attribute some factors with sources at ground level, and some other factors with sources in the upper part of surface layer. The impact of vertical turbulence on the pollutant dispersion is also affected by the distance between sources and receptor site. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Concentration, ozone formation potential and source analysis of volatile organic compounds (VOCs) in a thermal power station centralized area: A study in Shuozhou, China.

    Science.gov (United States)

    Yan, Yulong; Peng, Lin; Li, Rumei; Li, Yinghui; Li, Lijuan; Bai, Huiling

    2017-04-01

    Volatile organic compounds (VOCs) from two sampling sites (HB and XB) in a power station centralized area, in Shuozhou city, China, were sampled by stainless steel canisters and measured by gas chromatography-mass selective detection/flame ionization detection (GC-MSD/FID) in the spring and autumn of 2014. The concentration of VOCs was higher in the autumn (HB, 96.87 μg/m3; XB, 58.94 μg/m3) than in the spring (HB, 41.49 μg/m3; XB, 43.46 μg/m3), as lower wind speed in the autumn could lead to pollutant accumulation, especially at HB, which is a new urban area surrounded by residential areas and a transportation hub. Alkanes were the dominant group at both HB and XB in both sampling periods, but the contribution of aromatic pollutants at HB in the autumn was much higher than that of the other alkanes (11.16-19.55%). Compared to other cities, BTEX pollution in Shuozhou was among the lowest levels in the world. Because of the high levels of aromatic pollutants, the ozone formation potential increased significantly at HB in the autumn. Using the ratio analyses to identify the age of the air masses and analyze the sources, the results showed that the atmospheric VOCs at XB were strongly influenced by the remote sources of coal combustion, while at HB in the spring and autumn were affected by the remote sources of coal combustion and local sources of vehicle emission, respectively. Source analysis conducted using the Positive Matrix Factorization (PMF) model at Shuozhou showed that coal combustion and vehicle emissions made the two largest contributions (29.98% and 21.25%, respectively) to atmospheric VOCs. With further economic restructuring, the influence of vehicle emissions on the air quality should become more significant, indicating that controlling vehicle emissions is key to reducing the air pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Using vapor phase tomography to measure the spatial distribution of vapor concentrations and flux for vadose-zone VOC sources.

    Science.gov (United States)

    Mainhagu, J; Morrison, C; Brusseau, M L

    2015-01-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Anthropogenic VOC speciation in emission inventories: a method for improvement and evaluation

    Science.gov (United States)

    von Schneidemesser, E.; D'angiola, A.; Granier, C.; Monks, P. S.; Law, K.

    2011-12-01

    Volatile organic compounds (VOCs) are important precursor compounds for the formation of ozone and other secondary organic aerosols. Anthropogenic sources of VOCs are dominated by industrial usage and transportation sources, the latter being extremely important in urban areas. Megacities and large urban conglomerations are emission hot spots that exert disproportionately large adverse health effects on the population and surrounding environment, owing to their high population density and concentrated emission sources. Exceedances of ozone air quality standards are a problem in many urban areas. Improvements in the modelling of ozone precursors would benefit our understanding of the impact of changes in emissions and the effect of future legislation on air quality. As many VOCs are extremely reactive in the atmosphere and have high ozone forming potential, improved speciation of VOCs in models could lead to better predictions of ozone levels and secondary organic aerosol formation. Previously, VOC and carbon monoxide (CO) data from urban areas around the world were compared. Significant differences in VOC concentrations were observed, however, when normalized to CO, the VOC-CO ratios were similar for many locations and over time, even as emission reductions were implemented. The largest variation was found in the lighter alkanes due to the use of alternative transportation fuels in various world regions. These ratios were grouped by region and used to develop a new speciation for surface emissions of VOCs, by applying the regional observed VOC-CO ratios to the CO emissions for the urban areas. Urban areas were defined as 150 inhabitants per km2 or greater. Model simulations were performed using the MOZART-4 chemistry transport model to assess the improved speciation of the VOC emissions. The model outputs were compared to urban observational data where available. The impact of the new speciation of the distribution of CO, OH and ozone at the global scale will be

  12. Fiscal Year 2014 Source Reduction Assistance (SRA) Grant Summaries

    Science.gov (United States)

    The Office of Pollution Prevention and Toxics is responsible for overseeing several grant programs for tribes and states which promote pollution prevention through source reduction and resource conservation.

  13. Fiscal Year 2015 Source Reduction Assistance (SRA) Grant Summaries

    Science.gov (United States)

    The Office of Pollution Prevention and Toxics is responsible for overseeing several grant programs for tribes and states which promote pollution prevention through source reduction and resource conservation.

  14. Observation and modelling of OH and HO2 concentrations in Beijing and Pearl River Delta summer 2006: missing OH source in VOC rich atmosphere

    Science.gov (United States)

    Lu, K.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S.; Oebel, A.; Shao, M.; Zeng, L.; Zhu, T.; Wahner, A.; Zhang, Y.; Hofzumahaus, A.

    2011-12-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) and the CAREBEIJING2006 (Campaigns of Air Quality Research in Beijing and Surrounding Region, 2006) campaigns at rural sites close to the megacities of Guangzhou and Beijing, respectively. In PRD, the observed daily maximum OH and HO2 concentrations reached daily peak values of (15~--~26)±106 cm-3 and (3~--~25)±108 cm-3, respectively. In Beijing, the corresponding values were about (4~--~17)±106 cm-3 and (2~--~24)±108 cm-3. At both sites, the measured OH concentrations were much higher than can be explained by current chemical box models when NOx is low, pointing to a missing OH source in VOC rich air. In this presentation, we report the observed and modelled HOx concentrations, depict the general feature of the HOx system through an empirical analysis, and examine different mechanistic proposals to explain the missing OH source (Hofzumahaus et al. 2009; Lu et al., 2011). Overall, we conclude that a missing OH recycling of type HO2->OH is required for these VOC rich air masses in the transient regime between biogenic and urban influences. Recently published mechanistic updates of isoprene chemistry (e.g. MIM2+ and LIM0) developed for forest regions are not able to reproduce the observed OH in both PRD and Beijing.

  15. VOCs elimination and health risk reduction in e-waste dismantling workshop using integrated techniques of electrostatic precipitation with advanced oxidation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jiangyao [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Huang, Yong [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Guiying [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); An, Taicheng, E-mail: antc99@gig.ac.cn [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Hu, Yunkun; Li, Yunlu [Guangzhou Longest Environmental Science and Technology Co., Ltd., Guangzhou 510660 (China)

    2016-01-25

    Highlights: • Pilot-scale investigation of VOCs removal during e-waste dismantling process. • EP-PC-ozonation integrated reactor show high and stable removal ability to VOCs. • Health risks of target VOCs decrease significantly after the treatment. - Abstract: Volatile organic compounds (VOCs) emitted during the electronic waste dismantling process (EWDP) were treated at a pilot scale, using integrated electrostatic precipitation (EP)-advanced oxidation technologies (AOTs, subsequent photocatalysis (PC) and ozonation). Although no obvious alteration was seen in VOC concentration and composition, EP technology removed 47.2% of total suspended particles, greatly reducing the negative effect of particles on subsequent AOTs. After the AOT treatment, average removal efficiencies of 95.7%, 95.4%, 87.4%, and 97.5% were achieved for aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, as well as nitrogen- and oxygen-containing compounds, respectively, over 60-day treatment period. Furthermore, high elimination capacities were also seen using hybrid technique of PC with ozonation; this was due to the PC unit’s high loading rates and excellent pre-treatment abilities, and the ozonation unit’s high elimination capacity. In addition, the non-cancer and cancer risks, as well as the occupational exposure cancer risk, for workers exposed to emitted VOCs in workshop were reduced dramatically after the integrated technique treatment. Results demonstrated that the integrated technique led to highly efficient and stable VOC removal from EWDP emissions at a pilot scale. This study points to an efficient approach for atmospheric purification and improving human health in e-waste recycling regions.

  16. VOCs elimination and health risk reduction in e-waste dismantling workshop using integrated techniques of electrostatic precipitation with advanced oxidation technologies.

    Science.gov (United States)

    Chen, Jiangyao; Huang, Yong; Li, Guiying; An, Taicheng; Hu, Yunkun; Li, Yunlu

    2016-01-25

    Volatile organic compounds (VOCs) emitted during the electronic waste dismantling process (EWDP) were treated at a pilot scale, using integrated electrostatic precipitation (EP)-advanced oxidation technologies (AOTs, subsequent photocatalysis (PC) and ozonation). Although no obvious alteration was seen in VOC concentration and composition, EP technology removed 47.2% of total suspended particles, greatly reducing the negative effect of particles on subsequent AOTs. After the AOT treatment, average removal efficiencies of 95.7%, 95.4%, 87.4%, and 97.5% were achieved for aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, as well as nitrogen- and oxygen-containing compounds, respectively, over 60-day treatment period. Furthermore, high elimination capacities were also seen using hybrid technique of PC with ozonation; this was due to the PC unit's high loading rates and excellent pre-treatment abilities, and the ozonation unit's high elimination capacity. In addition, the non-cancer and cancer risks, as well as the occupational exposure cancer risk, for workers exposed to emitted VOCs in workshop were reduced dramatically after the integrated technique treatment. Results demonstrated that the integrated technique led to highly efficient and stable VOC removal from EWDP emissions at a pilot scale. This study points to an efficient approach for atmospheric purification and improving human health in e-waste recycling regions. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. VOC emissions chambers

    Data.gov (United States)

    Federal Laboratory Consortium — In order to support the development of test methods and reference materials for volatile organic compounds (VOC) emissions from building materials and furnishings,...

  18. Secondary inorganic aerosols in Europe: sources and the significant influence of biogenic VOC emissions, especially on ammonium nitrate

    Science.gov (United States)

    Aksoyoglu, Sebnem; Ciarelli, Giancarlo; El-Haddad, Imad; Baltensperger, Urs; Prévôt, André S. H.

    2017-06-01

    Contributions of various anthropogenic sources to the secondary inorganic aerosol (SIA) in Europe as well as the role of biogenic emissions on SIA formation were investigated using the three-dimensional regional model CAMx (comprehensive air quality model with extensions). Simulations were carried out for two periods of EMEP field campaigns, February-March 2009 and June 2006, which are representative of cold and warm seasons, respectively. Biogenic volatile organic compounds (BVOCs) are known mainly as precursors of ozone and secondary organic aerosol (SOA), but their role on inorganic aerosol formation has not attracted much attention so far. In this study, we showed the importance of the chemical reactions of BVOCs and how they affect the oxidant concentrations, leading to significant changes, especially in the formation of ammonium nitrate. A sensitivity test with doubled BVOC emissions in Europe during the warm season showed a large increase in secondary organic aerosol (SOA) concentrations (by about a factor of two), while particulate inorganic nitrate concentrations decreased by up to 35 %, leading to a better agreement between the model results and measurements. Sulfate concentrations decreased as well; the change, however, was smaller. The changes in inorganic nitrate and sulfate concentrations occurred at different locations in Europe, indicating the importance of precursor gases and biogenic emission types for the negative correlation between BVOCs and SIA. Further analysis of the data suggested that reactions of the additional terpenes with nitrate radicals at night were responsible for the decline in inorganic nitrate formation, whereas oxidation of BVOCs with OH radicals led to a decrease in sulfate. Source apportionment results suggest that the main anthropogenic source of precursors leading to formation of particulate inorganic nitrate is road transport (SNAP7; see Table 1 for a description of the categories), whereas combustion in energy and

  19. Use of Compound-Specific Stable Isotope Analysis to Distinguish Between Vapor Intrusion and Indoor Sources of VOCs

    Science.gov (United States)

    2013-11-01

    conduct room-by-room sampling by providing real -time results that facilitate the collection of source confirmation samples. However, the required...interferents in real samples are usually more abundant and diverse than in a matrix spike. The quality of GC separation has to be assessed by a trained...BUILDING 209 3/27/2013 8:31 Hall outside EPA/ ESAT Balance and Drying Oven Lab AI U U 3/27/2013 8:46 In hall by copy machine (across from Summa

  20. Evaluating a Space-Based Indicator of Surface Ozone-NOx-VOC Sensitivity Over Midlatitude Source Regions and Application to Decadal Trends

    Science.gov (United States)

    Jin, Xiaomeng; Fiore, Arlene M.; Murray, Lee T.; Valin, Lukas C.; Lamsal, Lok N.; Duncan, Bryan; Folkert Boersma, K.; De Smedt, Isabelle; Abad, Gonzalo Gonzalez; Chance, Kelly; Tonnesen, Gail S.

    2017-10-01

    Determining effective strategies for mitigating surface ozone (O3) pollution requires knowledge of the relative ambient concentrations of its precursors, NOx, and VOCs. The space-based tropospheric column ratio of formaldehyde to NO2 (FNR) has been used as an indicator to identify NOx-limited versus NOx-saturated O3 formation regimes. Quantitative use of this indicator ratio is subject to three major uncertainties: (1) the split between NOx-limited and NOx-saturated conditions may shift in space and time, (2) the ratio of the vertically integrated column may not represent the near-surface environment, and (3) satellite products contain errors. We use the GEOS-Chem global chemical transport model to evaluate the quantitative utility of FNR observed from the Ozone Monitoring Instrument over three northern midlatitude source regions. We find that FNR in the model surface layer is a robust predictor of the simulated near-surface O3 production regime. Extending this surface-based predictor to a column-based FNR requires accounting for differences in the HCHO and NO2 vertical profiles. We compare four combinations of two OMI HCHO and NO2 retrievals with modeled FNR. The spatial and temporal correlations between the modeled and satellite-derived FNR vary with the choice of NO2 product, while the mean offset depends on the choice of HCHO product. Space-based FNR indicates that the spring transition to NOx-limited regimes has shifted at least a month earlier over major cities (e.g., New York, London, and Seoul) between 2005 and 2015. This increase in NOx sensitivity implies that NOx emission controls will improve O3 air quality more now than it would have a decade ago.

  1. Catalytic oxidation of volatile organic compounds (VOCs) - A review

    Science.gov (United States)

    Kamal, Muhammad Shahzad; Razzak, Shaikh A.; Hossain, Mohammad M.

    2016-09-01

    Emission of volatile organic compounds (VOCs) is one of the major contributors to air pollution. The main sources of VOCs are petroleum refineries, fuel combustions, chemical industries, decomposition in the biosphere and biomass, pharmaceutical plants, automobile industries, textile manufacturers, solvents processes, cleaning products, printing presses, insulating materials, office supplies, printers etc. The most common VOCs are halogenated compounds, aldehydes, alcohols, ketones, aromatic compounds, and ethers. High concentrations of these VOCs can cause irritations, nausea, dizziness, and headaches. Some VOCs are also carcinogenic for both humans and animals. Therefore, it is crucial to minimize the emission of VOCs. Among the available technologies, the catalytic oxidation of VOCs is the most popular because of its versatility of handling a range of organic emissions under mild operating conditions. Due to that fact, there are numerous research initiatives focused on developing advanced technologies for the catalytic destruction of VOCs. This review discusses recent developments in catalytic systems for the destruction of VOCs. Review also describes various VOCs and their sources of emission, mechanisms of catalytic destruction, the causes of catalyst deactivation, and catalyst regeneration methods.

  2. Removal of Volatile Organic Contaminants (VOCs) from the Groundwater Sources of Drinking Water via Granular Activated Carbon Treatment (WaterRF Report 4440)

    Science.gov (United States)

    The overall goal of this project was to assess the feasibility of granular activated carbon (GAC) for the treatment of selected carcinogenic volatile organic compounds (cVOC) to sub-μg/L levels. The project consisted of three tasks. The task objectives are: Task I - determine c...

  3. Evaluating a Space-Based Indicator of Surface Ozone-NOx-VOC Sensitivity Over Midlatitude Source Regions and Application to Decadal Trends

    Science.gov (United States)

    Determining effective strategies for mitigating surface ozone (O3) pollution requires knowledge of the relative ambient concentrations of its precursors, NOx, and VOCs. The space-based tropospheric column ratio of formaldehyde to NO2 (FNR) has been used as an indicator to identif...

  4. Supersonic Jet Noise: Main Sources and Reduction Methodologies

    Directory of Open Access Journals (Sweden)

    Mohammadreza Azimi

    2014-07-01

    Full Text Available The large velocity ratio and the presence of Shocks in the exhaust plume from low bypass engines or supersonic jetliners cause jet noise to be dominant component of overall aircraft noise, and therefore is an important issue in design of the next generation of civil supersonic transport. Jet noise reduction technology also has application in the design of highperformance tactical aircraft. Jet noise is of particular concern on aircraft carriers where it is necessary for deck crew to be in relatively close proximity to the aircraft at takeoff and landing. In this paper, a brief discussion about supersonic jet noise sources and a review of the main passive technologies employed for the reduction of supersonic jet noise are presented.

  5. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    Science.gov (United States)

    Lu, K. D.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C. C.; Häseler, R.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Nehr, S.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhang, Y. H.; Hofzumahaus, A.

    2012-02-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) × 106 cm-3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the

  6. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    Directory of Open Access Journals (Sweden)

    M. Shao

    2012-02-01

    Full Text Available Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006 campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15–26 × 106 cm−3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009 proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008 and Peeters and Müller (2010 lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1–0.2 ppb. If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and M

  7. Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions. Part II: source contribution assessment using the Chemical Mass Balance (CMB) model.

    Science.gov (United States)

    Badol, Caroline; Locoge, Nadine; Galloo, Jean-Claude

    2008-01-25

    In Part I of this study (Badol C, Locoge N, Leonardis T, Gallo JC. Using a source-receptor approach to characterise VOC behaviour in a French urban area influenced by industrial emissions, Part I: Study area description, data set acquisition and qualitative data analysis of the data set. Sci Total Environ 2007; submitted as companion manuscript.) the study area, acquisition of the one-year data set and qualitative analysis of the data set have been described. In Part II a source profile has been established for each activity present in the study area: 6 profiles (urban heating, solvent use, natural gas leakage, biogenic emissions, gasoline evaporation and vehicle exhaust) have been extracted from literature to characterise urban sources, 7 industrial profiles have been established via canister sampling around industrial plants (hydrocarbon cracking, oil refinery, hydrocarbon storage, lubricant storage, lubricant refinery, surface treatment and metallurgy). The CMB model is briefly described and its implementation is discussed through the selection of source profiles and fitting species. Main results of CMB modellings for the Dunkerque area are presented. (1) The daily evolution of source contributions for the urban wind sector shows that the vehicle exhaust source contribution varies between 40 and 55% and its relative increase at traffic rush hours is hardly perceptible. (2) The relative contribution of vehicle exhaust varies from 55% in winter down to 30% in summer. This decrease is due to the increase of the relative contribution of hydrocarbon storage source reaching up to 20% in summer. (3) The evolution of source contributions with wind directions has confirmed that in urban wind sectors the contribution of vehicle exhaust dominate with around 45-55%. For the other wind sectors that include some industrial plants, the contribution of industrial sources is around 60% and could reach 80% for the sector 280-310 degrees , which corresponds to the most dense

  8. POCP for individual VOC under European conditions

    Energy Technology Data Exchange (ETDEWEB)

    Altenstedt, J.; Pleijel, K.

    1998-09-01

    Ground level ozone has been recognised as one of the most important environmental threats on the regional scale in Europe. Ozone is today considered to be harmful to human health already at the relatively low concentrations present in southern Scandinavia. The fact that ozone has the potential to damage vegetation at these concentrations is already well known. Ozone also gives rise to degradation of materials and is one of the gases which adds to the greenhouse effect. Ground level ozone is formed from nitrogen oxides (NO{sub x}) and volatile organic compounds (VOC) in the presence of sunlight. The only way to reduce ozone is therefore to reduce the emissions of the precursors. Ranking individual VOC by their ozone formation potential can make emission reductions more environmentally efficient and save time and money. POCP values give a ranking of the ozone formation ability of an individual VOC relative to other VOC. A critical analysis of the POCP concept has been performed which shows that the background emissions of NO{sub x} and VOC affect the POCP values to a large extent. Based on the critical analysis, five scenarios with different background emissions of NO{sub x} and VOC were selected for calculation of POCP values. These scenarios were chosen because they reflect the variation in POCP values which arise in different environments within Europe. The range thus indicates POCP values which are intended to be applicable within Europe. POCP values for 83 different VOC are presented in the form of ranges in this report. 42 refs, 13 figs, 3 tabs

  9. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  10. Volatile Organic Compounds (VOCs)

    Science.gov (United States)

    ... their MCLs: Organic Chemicals U.S. Geology Survey's National Water-Quality Assessment (NAWQA) Program Information on VOCs in Water ... Waste, and Cleanup Lead Mold Pesticides Radon Science Water A-Z Index Laws & Regulations By Business Sector By Topic Compliance ...

  11. Shallow vs. Deep Fluid Sources In Hydrothermal Systems: New Insights From VOC Composition In Fumarolic Discharges And Soil Gases Of Yellowstone National Park (USA)

    Science.gov (United States)

    Tassi, F.; Capecchiacci, F.; Montegrossi, G.; Caliro, S.; Chiodini, G.; Vaselli, O.

    2008-12-01

    The origin of non-methane volatile organic compounds (VOCs) in hydrothermal fluids is related to two distinct mechanisms regulated by different thermodynamic conditions (e.g. Des Marais et al., 1981; Mango, 2000; Capaccioni and Mangani, 2001): i) thermogenic reactions, such as catalytic reforming and/or thermal cracking, which proceed within the main reservoir at medium-to-high temperature (150-350°C) and reduced conditions; ii) biodegradation processes, occurring at relatively shallow depth, where uprising fluids have Food Chem., 56, 789- 795. Capaccioni, B., Mangani, F., 2001. Earth Planet. Sci. Lett., 188, 543-555. Des Marais, D.J., Donchin, J.H., Truesdell, A.H., Nehring, N.L., 1981. Nature, 292, 826-828. Mango, F.D., 2000. Geochim. Cosmochim. Acta, 64, 1265-1277.

  12. SPECIATED VOC EMISSIONS FROM MODERN GDI LIGHT DUTY VEHICLES

    Science.gov (United States)

    Chassis dynamometer emissions testing was conducted to characterize speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs) and ozone precursors, in exhaust emissions from three modern gasoline direct injection (GDI) light-duty vehicles. Each GDI v...

  13. VOC Measurements in the Northern Colorado Front Range Metropolitan Area: Investigating the Impact of Oil and Natural Gas Emissions on O3 Production

    Science.gov (United States)

    Abeleira, A.; Farmer, D.; Fischer, E. V.; Pollack, I. B.; Zaragoza, J.

    2015-12-01

    Authors: Ilana Pollock1,2, Jake Zaragoza2, Emily V. Fischer2, Delphine K. Farmer11. Department of Chemistry, Colorado State University, Fort Collins, CO 2. Department of Atmospheric Science, Colorado State University, Fort Collins, CO During summer months, the Northern Front Range Metropolitan Area (NFRMA) of Colorado consistently violates the 75 ppbv 8-hour EPA National Ambient Air Quality Standard (NAAQS) for ambient ozone (O3), despite continued reduction in anthropogenic emissions. The region has been deemed an O3 non-attainment zone since 2008. Ground-level O3 is produced from photochemical catalytic cycles involving OH radicals, volatile organic compounds (VOCs), and NOx (NO + NO2). VOC emissions in the NFRMA are dominated by anthropogenic sources and influenced by biogenic and agricultural sources, while NOx emissions are mainly from automobile exhaust. A growing concern in the region is the role of oil and natural gas (ONG) on VOC concentrations and the potential for O3 production. Increases in local VOC emissions will likely cause subsequent increase in local O3 concentrations as PO3 increases in a region that is already affected by high O3episodes. As a part of the SONGNEX 2015 (Shale Oil and Natural Gas Nexus) campaign, we measured a broad suite of speciated VOCs during two 8-week deployments (March-May 2015, July-September 2015) at the Boulder Atmospheric Observatory in Erie, CO. VOC measurements were made with a custom-online multichannel gas chromatography system (50+ compounds hourly), along with measurements of O3, SO2, NOx, NOy, PAN, CO, CO2, and CH4. We use these data to investigate the role of different VOC sources, and ONG in particular, in contributing to VOC reactivity and thus instantaneous O3 production. Preliminary analysis of the Spring VOC data indicates that VOC reactivity is dominated by light alkanes typical of ONG emissions - specifically propane, consistent with previous winter-time studies. We will use the observed temperature

  14. Crouching Tiger, Hidden Trouble: Urban Sources of Aedes albopictus (Diptera: Culicidae) Refractory to Source-Reduction

    Science.gov (United States)

    Unlu, Isik; Farajollahi, Ary; Strickman, Daniel; Fonseca, Dina M.

    2013-01-01

    Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years.  We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive

  15. Dejima VOC dan rangaku

    Directory of Open Access Journals (Sweden)

    Bambang Wibawarta

    2008-10-01

    Full Text Available Japan and the Netherlands have maintained a special relationship for about 300years since the adoption of the National Seclusion policy, the so-called sakoku bythe Tokugawa shogunate (1603-1867. The Dutch began trading with Japan andengaging with Japanese society in 1600, when a Dutch ship, De Liefde, arrived inKyushu. The Tokugawa government measures regarding foreign policy includedregulations on foreign access to Japan and a prohibition on Japanese goingabroad. Between the middle of the seventeenth to the early nineteenth century,Japan was characterized by a stable political pattern in which representativesof the VOC (Dutch East India Company, were the only Europeans with a rightto trade in Japan. In the course of this period, the Japanese evaluation of theDutch changed from regarding them as commercial agents to seeing them asimporters of European knowledge. This paper is especially concerned with theinfluence of the so-called ‘Dutch Studies’ (rangaku on the early modernizationof Japan, especially with regard to medicine and the natural sciences. Thisresearch examines the development of rangaku and the trading between Japanand VOC at Dejima.

  16. Scanning Reduction Strategy in MEG/EEG Beamformer Source Imaging

    Directory of Open Access Journals (Sweden)

    Jun Hee Hong

    2012-01-01

    Full Text Available MEG/EEG beamformer source imaging is a promising approach which can easily address spatiotemporal multi-dipole problems without a priori information on the number of sources and is robust to noise. Despite such promise, beamformer generally has weakness which is degrading localization performance for correlated sources and is requiring of dense scanning for covering all possible interesting (entire source areas. Wide source space scanning yields all interesting area images, and it results in lengthy computation time. Therefore, an efficient source space scanning strategy would be beneficial in achieving accelerated beamformer source imaging. We propose a new strategy in computing beamformer to reduce scanning points and still maintain effective accuracy (good spatial resolution. This new strategy uses the distribution of correlation values between measurements and lead-field vectors. Scanning source points are chosen yielding higher RMS correlations than the predetermined correlation thresholds. We discuss how correlation thresholds depend on SNR and verify the feasibility and efficacy of our proposed strategy to improve the beamformer through numerical and empirical experiments. Our proposed strategy could in time accelerate the conventional beamformer up to over 40% without sacrificing spatial accuracy.

  17. [Countermeasures for priority control of toxic VOC pollution].

    Science.gov (United States)

    Chen, Ying; Li, Li-Na; Yang, Chang-Qing; Hao, Zheng-Ping; Sun, Han-Kun; Li, Yao

    2011-12-01

    VOC pollution is worsening, not only affects the environment, air quality, but also directly harm human health, and Chinese relevant departments need to improve control measures. U. S. toxic air pollutants (HAPs) control system was studied, and Chinese environment countermeasures were proposed based on pollution features. U. S. recognized sources of hazardous air pollutants in the Clean Air Act (CAA), and reduced their emissions by industrial regulations and regional policies. In urban areas, VOC occupied a great part of toxic air and were controlled as a major project in U. S. Due to relatively weak management and technical base, China should screen some VOC components for priority pollutant control. The feature of Chinese VOC pollution was described as complex components, industry sources widely distributed, strong regional characteristics and processes, and gradual development of regional pollution. It was suggested to carry out investigation assessment activities, enhance cumulative risk assessment and environmental impact assessment management, and strengthen emergency risk prevention.

  18. Application of OMI Observations to a Space-Based Indicator of NOx and VOC Controls on Surface Ozone Formation

    Science.gov (United States)

    Duncan, Bryan N.; Yoshida, Yasuko; Olson, Jennifer R.; Sillman, Sanford; Martin, Randall V.; Lamsal, Lok; Hu, Yongtao; Pickering, Kenneth E.; Retscher, Christian; Allen, Dale J.; hide

    2010-01-01

    We investigated variations in the relative sensitivity of surface ozone formation in summer to precursor species concentrations of volatile organic compounds (VOCs) and nitrogen oxides (NOx) as inferred from the ratio of the tropospheric columns of formaldehyde to nitrogen dioxide (the "Ratio") from the Aura Ozone Monitoring Instrument (OMI). Our modeling study suggests that ozone formation decreases with reductions in VOCs at Ratios less than 1 and NOx at Ratios greater than 2; both NOx and VOC reductions may decrease ozone formation for Ratios between 1 and 2. Using this criteria. the OMI data indicate that ozone formation became: 1. more sensitive to NOx over most of the United States from 2005 to 2007 because of the substantial decrease in NOx emissions, primarily from stationary sources, and the concomitant decrease in the tropospheric column of NO2. and 2. more sensitive to NOx with increasing temperature, in part because emissions of highly reactive, biogenic isoprene increase with temperature, thus increasing the total VOC reactivity. In cities with relatively low isoprene emissions (e.g .. Chicago). the data clearly indicate that ozone formation became more sensitive to NOx from 2005 to 2007. In cities with relatively high isoprene emissions (e.g ., Atlanta), we found that the increase in the Ratio due to decreasing NOx emissions was not obvious as this signal was convolved with variations in the Ratio associated with the temperature dependence of isoprene emissions and, consequently, the formaldehyde concentration.

  19. Influence of adhesive bonding on quantity of emissions VOCs

    Directory of Open Access Journals (Sweden)

    Petr Čech

    2008-01-01

    Full Text Available The study deals with the influence of urea-formaldehyde glue and veneered bolstering on technological operation veneering on quantity of emission VOCs (volatile organic compounds.The so-called Volatile Organic Compounds (VOC are among the largest pollution sources of both the internal and external environments.VOC is defined as emission of any organic compound or a mixture thereof, with the exception of methane, whereby the compound exerts the pressure of 0.01 kPa or more at the temperature of 20 °C (293.15 K and reaches the corresponding volatility under the specific conditions of its use and can undergo photochemical reactions with nitrogen oxides when exposed to solar radiation.The effects of VOC upon environment can be described by equation:VOC + NOx + UV radiation + heat = tropospheric ozone (O3.In this work there were tested background working environment in various parts of multi-storeyed press, next was judged emissive charge of veneered device and used glue. We used surface material such as chipboard. We used urea-formaldehyde glue KRONOCOL U300 on technological operation veneering.The VOC emissions from the wooden surfaces with or without finishing were tested in the Equipment for VOC Measuring with a small-space chamber. This equipment was installed in and made available by the Institute of Furniture, Design and Habitation. The small-space chamber is suitable for testing small parts of wood products. The device equipped with small-chamber satisfies all conditions mandated in the standard ENV 13 419 DIN -V-ENV 13 419 ”Determination of the emissions of Volatile organic compounds”.The VOC emissions were collected in columns with sorbent Tenax TA. We analyzed the columns with the VOC emissions by: the gas chromatography in conjunction with mass spectrometer and Direct Thermal Desorption.

  20. Thermal response and recyclability of poly(stearylacrylate-co-ethylene glycol dimethacrylate) gel as a VOCs absorbent

    Science.gov (United States)

    The development of absorbent materials for volatile organic compounds (VOCs) is in demand for a variety of environmental applications including protective barriers for VOCs point sources. One of the challenges for the currently available VOCs absorbents is their recyclability. In this study, we syn...

  1. Disaster Risk Reduction through Innovative Uses of Crowd Sourcing (Invited)

    Science.gov (United States)

    Berger, J.; Greene, M.

    2010-12-01

    Crowd sourcing can be described as a method of distributed problem-solving. It takes advantage of the power of the crowd, which can in some cases be a community of experts and in other cases the collective insight of a broader range of contributors with varying degrees of domain knowledge. The term crowd sourcing was first used by Jeff Howe in a June 2006 Wired magazine article “The Rise of Crowdsourcing,” and is a combination of the terms “crowd” and “outsourcing.” Some commonly known examples of crowd sourcing, in its broadest sense, include Wikepedia, distributed participatory design projects, and consumer websites such as Yelp and Angie’s List. The popularity and success of early large-scale crowd sourcing activities is made possible through leveraging Web 2.0 technologies that allow for mass participation from distributed individuals. The Earthquake Engineering Research Institute (EERI) in Oakland, California recently participated in two crowd sourcing projects. One was initiated and coordinated by EERI, while in the second case EERI was invited to contribute once the crowd sourcing activity was underway. In both projects there was: 1) the determination of a problem or set of tasks that could benefit immediately from the engagement of an informed volunteer group of professionals; 2) a segmenting of the problem into discrete pieces that could be completed in a short period of time (from ten minutes to four hours); 3) a call to action, where an interested community was made aware of the project; and 4) the collection, aggregation, vetting and ultimately distribution of the results in a relatively short period of time. The first EERI crowd sourcing example was the use of practicing engineers and engineering students in California to help estimate the number of pre-1980 concrete buildings in the high seismic risk counties in the state. This building type is known to perform poorly in earthquakes, and state officials were interested in understanding

  2. Emission control measures for precursors of tropospheric ozone. Pt. 1 and 2; Emissionsminderungsmoeglichkeiten bei Vorlaeufersubstanzen von bodennahem Ozon. Bd. 1: Systemanalyse der Ozonminderungsmassnahmen in den USA. Bd. 2: Luftreinhaltemassnahmen in den USA zur Minderung von VOC-Emissionen aus Kleinanlagen und Produkten und Vergleich mit europaeischen Regelungen

    Energy Technology Data Exchange (ETDEWEB)

    Leclaire, T.; Schiefer, C.; Bergmann, S.; Hrabovski, Z. [Institut fuer Umwelttechnologie und Umweltanalytik e.V. (IUTA), Duisburg (Germany)

    1998-08-01

    For more than two decades now experiences of ozone reduction have been made in the USA. In many regions great efforts for VOC control are made to reduce their high ozone concentrations in ambient air that in some cases reach up to more than twice the German peak concentrations. This report places focus on small stationary sources and products, for these sources actually contribute more than half of the VOC emissions in Germany and are still not regulated under the German Immission Control Law. Therefore, main aim of this examination was to determine the major elements of VOC control strategies in the U.S. and to consider, whether strategies and measures are transferable taking into account German circumstances. Volume 1 describes the strategies and measures for ozone control in the U.S. (national) as well as in five regions with high ozone concentrations in ambient air. The authorities and responsbilities at federal, state, regional, and local levels are highlighted, legislation and different types of regulations are explained, priorities concerning VOC versus NO{sub x} related control are mentioned and the control measures on different sources for reducing VOC and NO{sub x} are summarized briefly. Volume 2 contains a detailed description of control measures for reducing VOC emissions from products and stationary sources, namely the proposed national VOC emission standards for coatings and consumer products, the California Consumer Products Regulations, the state-wide requirements for industrial and commercial sources in California and the VOC related rules of the South Coast Air Quality Management District (LA and surrounded Countries). The South Coast Rules were chosen as an example for District Rules for they were generally the most stringent because of the extreme ozone concentration in this area. Moreover, the regulations for VOC emission control in Europe concerning small stationary sources and products are mentioned. The different approaches to control VOC

  3. Effect of VOC Emissions from Vegetation on Air Quality in Berlin during a Heatwave.

    Science.gov (United States)

    Churkina, Galina; Kuik, Friderike; Bonn, Boris; Lauer, Axel; Grote, Rüdiger; Tomiak, Karolina; Butler, Tim M

    2017-06-06

    The potential of emissions from urban vegetation combined with anthropogenic emissions to produce ozone and particulate matter has long been recognized. This potential increases with rising temperatures and may lead to severe problems with air quality in densely populated areas during heat waves. Here, we investigate how heat waves affect emissions of volatile organic compounds from urban/suburban vegetation and corresponding ground-level ozone and particulate matter. We use the Weather Research and Forecasting Model with atmospheric chemistry (WRF-Chem) with emissions of volatile organic compounds (VOCs) from vegetation simulated with MEGAN to quantify some of these feedbacks in Berlin, Germany, during the heat wave in 2006. The highest ozone concentration observed during that period was ∼200 μg/m3 (∼101 ppbV). The model simulations indicate that the contribution of biogenic VOC emissions to ozone formation is lower in June (9-11%) and August (6-9%) than in July (17-20%). On particular days within the analyzed heat wave period, this contribution increases up to 60%. The actual contribution is expected to be even higher as the model underestimates isoprene concentrations over urban forests and parks by 0.6-1.4 ppbv. Our study demonstrates that biogenic VOCs can considerably enhance air pollution during heat waves. We emphasize the dual role of vegetation for air quality and human health in cities during warm seasons, which is removal and lessening versus enhancement of air pollution. The results of our study suggest that reduction of anthropogenic sources of NOx, VOCs, and PM, for example, reduction of the motorized vehicle fleet, would have to accompany urban tree planting campaigns to make them really beneficial for urban dwellers.

  4. Determinants of personal, indoor and outdoor VOC concentrations: an analysis of the RIOPA data.

    Science.gov (United States)

    Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

    2013-10-01

    Community and environmental exposure to volatile organic compounds (VOCs) has been associated with a number of emission sources and activities, e.g., environmental tobacco smoke and pumping gasoline. Such factors have been identified from mostly small studies with relatively limited information regarding influences on VOC levels. This study uses data from the Relationship of Indoor Outdoor and Personal Air (RIOPA) study to investigate environmental, individual and social determinants of VOC concentrations. RIOPA included outdoor, indoor and personal measurements of 18 VOCs from 310 non-smoking households and adults in three cities and two seasons, and collected a wide range of information pertaining to participants, family members, households, and neighborhoods. Exposure determinants were identified using stepwise regressions and linear mixed-effect models. Most VOC exposure (66 to 78% of the total exposure, depending on VOC) occurred indoors, and outdoor VOC sources accounted for 5 (d-limonene) to 81% (carbon tetrachloride) of the total exposure. Personal exposure and indoor measurements had similar determinants, which depended on the VOC. Gasoline-related VOCs (e.g., benzene, methyl tertiary butyl ether) were associated with city, residences with attached garages, self-pumping of gas, wind speed, and house air exchange rate (AER). Odorant and cleaning-related VOCs (e.g., 1,4-dichlorobenzene and chloroform) also were associated with city and AER, and with house size and family members showering. Dry-cleaning and industry-related VOCs (e.g., tetrachloroethylene and trichloroethylene) were associated with city, residence water supply type, and dry-cleaner visits. These and other relationships were significant, explained from 10 to 40% of the variation, and are consistent with known emission sources and the literature. Outdoor concentrations had only two common determinants: city and wind speed. Overall, personal exposure was dominated by the home setting, although a

  5. An Air Quality Data Analysis System for Interrelating Effects, Standards and Needed Source Reductions

    Science.gov (United States)

    Larsen, Ralph I.

    1973-01-01

    Makes recommendations for a single air quality data system (using average time) for interrelating air pollution effects, air quality standards, air quality monitoring, diffusion calculations, source-reduction calculations, and emission standards. (JR)

  6. Volatile Organic Compound (VOC measurements in the Pearl River Delta (PRD region, China

    Directory of Open Access Journals (Sweden)

    Chih-chung Chang

    2008-03-01

    Full Text Available We measured levels of ambient volatile organic compounds (VOCs at seven sites in the Pearl River Delta (PRD region of China during the Air Quality Monitoring Campaign spanning 4 October to 3 November 2004. Two of the sites, Guangzhou (GZ and Xinken (XK, were intensive sites at which we collected multiple daily canister samples. The observations reported here provide a look at the VOC distribution, speciation, and photochemical implications in the PRD region. Alkanes constituted the largest percentage (>40% in mixing ratios of the quantified VOCs at six sites; the exception was one major industrial site that was dominated by aromatics (about 52%. Highly elevated VOC levels occurred at GZ during two pollution episodes; however, the chemical composition of VOCs did not exhibit noticeable changes during these episodes. We calculated the OH loss rate to estimate the chemical reactivity of all VOCs. Of the anthropogenic VOCs, alkenes played a predominant role in VOC reactivity at GZ, whereas the contributions of reactive aromatics were more important at XK. Our preliminary analysis of the VOC correlations suggests that the ambient VOCs at GZ came directly from local sources (i.e., automobiles; those at XK were influenced by both local emissions and transportation of air mass from upwind areas.

  7. Comparison between sucrose, ethanol and methanol as carbon and energy sources for biological sulphate reduction

    CSIR Research Space (South Africa)

    Greben, HA

    2000-01-01

    Full Text Available , ethanol and methanol as a carbon and energy sources. The presented results indicated that sugar and ethanol were found to be suitable carbon and energy sources resulting in a volumetric and a specific sulphate reduction rate of 10.4 and 4.8 g SO4(l...

  8. Plant leaves as indoor air passive samplers for volatile organic compounds (VOCs).

    Science.gov (United States)

    Wetzel, Todd A; Doucette, William J

    2015-03-01

    Volatile organic compounds (VOCs) enter indoor environments through internal and external sources. Indoor air concentrations of VOCs vary greatly but are generally higher than outdoors. Plants have been promoted as indoor air purifiers for decades, but reports of their effectiveness differ. However, while air-purifying applications may be questionable, the waxy cuticle coating on leaves may provide a simple, cost-effective approach to sampling indoor air for VOCs. To investigate the potential use of plants as indoor air VOC samplers, a static headspace approach was used to examine the relationship between leaf and air concentrations, leaf lipid contents and octanol-air partition coefficients (Koa) for six VOCs and four plant species. The relationship between leaf and air concentrations was further examined in an actual residence after the introduction of several chlorinated VOC emission sources. Leaf-air concentration factors (LACFs), calculated from linear regressions of the laboratory headspace data, were found to increase as the solvent extractable leaf lipid content and Koa value of the VOC increased. In the studies conducted in the residence, leaf concentrations paralleled the changing air concentrations, indicating a relatively rapid air to leaf VOC exchange. Overall, the data from the laboratory and residential studies illustrate the potential for plant leaves to be used as cost effective, real-time indoor air VOC samplers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Ambient volatile organic compound (VOC) concentrations around a petrochemical complex and a petroleum refinery.

    Science.gov (United States)

    Cetin, Eylem; Odabasi, Mustafa; Seyfioglu, Remzi

    2003-08-01

    Air samples were collected between September 2000 and September 2001 in Izmir, Turkey at three sampling sites located around a petrochemical complex and an oil refinery to measure ambient volatile organic compound (VOC) concentrations. VOC concentrations were 4-20-fold higher than those measured at a suburban site in Izmir, Turkey. Ethylene dichloride, a leaded gasoline additive used in petroleum refining and an intermediate product of the vinyl chloride process in the petrochemical complex, was the most abundant volatile organic compound, followed by ethyl alcohol and acetone. Evaluations based on wind direction clearly indicated that ambient VOC concentrations measured were affected by the refinery and petrochemical complex emissions. VOC concentrations showed seasonal variations at all sampling sites. Concentrations were highest in summer, followed by autumn, probably due to increased evaporation of VOCs from fugitive sources as a result of higher temperatures. VOC concentrations generally increased with temperature and wind speed. Temperature and wind speed together explained 1-60% of the variability in VOC concentrations. The variability in ambient VOC concentrations that could not be explained by temperature and wind speed can be attributed to the effect of other factors (i.e. wind direction, other VOC sources).

  10. Characterization of ambient volatile organic compounds and their sources in Beijing, before, during, and after Asia-Pacific Economic Cooperation China 2014

    Science.gov (United States)

    Li, J.; Xie, S. D.; Zeng, L. M.; Li, L. Y.; Li, Y. Q.; Wu, R. R.

    2015-07-01

    Ambient volatile organic compounds (VOCs) were measured using an online system, gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID), in Beijing, China, before, during, and after Asia-Pacific Economic Cooperation (APEC) China 2014, when stringent air quality control measures were implemented. Positive matrix factorization (PMF) was applied to identify the major VOC contributing sources and their temporal variations. The secondary organic aerosols potential (SOAP) approach was used to estimate variations of precursor source contributions to SOA formation. The average VOC mixing ratios during the three periods were 86.17, 48.28, and 72.97 ppbv, respectively. The mixing ratios of total VOC during the control period were reduced by 44 %, and the mixing ratios of acetonitrile, halocarbons, oxygenated VOCs (OVOCs), aromatics, acetylene, alkanes, and alkenes decreased by approximately 65, 62, 54, 53, 37, 36, and 23 %, respectively. The mixing ratios of all measured VOC species decreased during control, and the most affected species were chlorinated VOCs (chloroethane, 1,1-dichloroethylene, chlorobenzene). PMF analysis indicated eight major sources of ambient VOCs, and emissions from target control sources were clearly reduced during the control period. Compared with the values before control, contributions of vehicular exhaust were most reduced, followed by industrial manufacturing and solvent utilization. Reductions of these three sources were responsible for 50, 26, and 16 % of the reductions in ambient VOCs. Contributions of evaporated or liquid gasoline and industrial chemical feedstock were slightly reduced, and contributions of secondary and long-lived species were relatively stable. Due to central heating, emissions from fuel combustion kept on increasing during the whole campaign; because of weak control of liquid petroleum gas (LPG), the highest emissions of LPG occurred in the control period. Vehicle-related sources were the most important

  11. Characteristics of Ambient Volatile Organic Compounds (VOCs Measured in Shanghai, China

    Directory of Open Access Journals (Sweden)

    Guang-Qiang Zhou

    2010-08-01

    Full Text Available To better understand the characteristics of ambient abundance of volatile organic compounds (VOCs in Shanghai, one of the biggest metropolis of China, VOCs were measured with a gas chromatography system equipped with a mass-selective detector (GC/MSD from July 2006 to February 2010. An intensive measurement campaign was conducted (eight samples per day with a 3 hour interval during May 2009. The comparison of ambient VOCs collected in different regions of Shanghai shows that the concentrations are slightly higher in the busy commercial area (28.9 ppbv at Xujiaui than in the urban administrative area (24.3 ppbv at Pudong. However, during the intensive measurement period, the concentrations in the large steel industrial area (28.7 ppbv at Baoshan were much higher than in the urban administrative area (18 ppbv at Pudong, especially for alkanes, alkenes, and toluene. The seasonal variations of ambient VOC concentrations measured at the Xujiahui sampling site indicate that the VOC concentrations are significantly affected by meteorological conditions (such as wind direction and precipitation. In addition, although alkanes are the most abundant VOCs at the Xujiahui measurement site, the most important VOCs contributing to ozone formation potential (OFP are aromatics, accounting for 57% of the total OFP. The diurnal variations of VOC concentrations show that VOC concentrations are higher on weekdays than in weekends at the Xujiahui sampling site, suggesting that traffic condition and human activities have important impacts on VOC emissions in Shanghai. The evidence also shows that the major sources of isoprene are mainly resulted from gasoline evaporation at a particular time (06:00–09:00 in the busy commercial area. The results gained from this study provide useful information for better understanding the characteristics of ambient VOCs and the sources of VOCs in Shanghai.

  12. Effect of traffic restriction on reducing ambient volatile organic compounds (VOCs): Observation-based evaluation during a traffic restriction drill in Guangzhou, China

    Science.gov (United States)

    Huang, Xinyu; Zhang, Yanli; Yang, Weiqiang; Huang, Zuzhao; Wang, Yujun; Zhang, Zhou; He, Quanfu; Lü, Sujun; Huang, Zhonghui; Bi, Xinhui; Wang, Xinming

    2017-07-01

    Traffic restriction (TR) is a widely adopted control measure in case of heavy air pollution particularly in urban areas, yet it is hard to evaluate the effect of TR on reducing VOC emissions based on monitoring data since ambient VOC mixing ratios are influenced not only by source emissions but also by meteorological conditions and atmospheric degradation. Here we collected air samples for analysis of VOCs before, during and after a TR drill carried out in Guangzhou in September 2010 at both a roadside and a rooftop (∼50 m above the ground) site. TR measures mainly included the ;odd-even license; rule and banning high-emitting ;yellow label; vehicles. The mixing ratios of non-methane hydrocarbons (NMHCs) did not show significant changes at the roadside site with total NMHCs of 39.0 ± 11.8 ppbv during non-TR period and 39.1 ± 14.8 ppbv during TR period, whereas total NMHCs decreased from 30.4 ± 14.3 ppbv during the non-TR period to 22.1 ± 10.6 ppbv during the TR period at rooftop site. However, the ratios of methyl tert-butyl ether (MTBE), benzene and toluene against carbon monoxide (MTBE/CO, T/CO and B/CO) at the both sampling sites dropped significantly. The ratios of toluene to benzene (T/B) instead increased significantly. Changes in these ratios all consistently indicated reduced input from traffic emissions particularly gasoline vehicles. Source attribution by positive matrix factorization (PMF) confirmed that during the TR period gasoline vehicles contributed less VOCs in percentages while industrial sources, biomass burning and LPG shared larger percentages. Assuming that emissions from industrial sources remained unchanged during the TR and non-TR periods, we further used the PMF-retrieved contribution percentages to deduce the reduction rate of traffic-related VOC emissions, and obtained a reduction rate of 31% based on monitoring data at the roadside site and of 34% based on the monitoring data at the rooftop site. Considering VOC emissions from all

  13. 40 CFR 60.502 - Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals.

    Science.gov (United States)

    2010-07-01

    ... (VOC) emissions from bulk gasoline terminals. 60.502 Section 60.502 Protection of Environment... SOURCES Standards of Performance for Bulk Gasoline Terminals § 60.502 Standard for Volatile Organic Compound (VOC) emissions from bulk gasoline terminals. On and after the date on which § 60.8(a) requires a...

  14. Comparative assessments of VOC emission rates and associated health risks from wastewater treatment processes.

    Science.gov (United States)

    Yang, Wen-Ben; Chen, Wei-Hsiang; Yuan, Chung-Shin; Yang, Jun-Chen; Zhao, Qing-Liang

    2012-09-01

    With the growing concern regarding emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs), the relationship between the VOC emission rates and the associated public health risks has been rarely discussed. The objective of this study was to examine and compare the VOC emission rates and cancer and non-cancer risks by inhalation intake, using a municipal WWTP in China as an example, with respect to the effects of treatment technologies, VOC species, and seasonal variation. Given the treatment technology considered, the emission rates of VOCs in this study were estimated by means of mass balance or calculated on the molecular level. From the viewpoints of both emission rates and cancer and non-cancer risks, sedimentation was the treatment technology with the highest health risks to the workers. Slightly lower VOC emission rates and health risks than those for sedimentation were observed in anaerobic treatment. Although the aeration significantly enhanced the VOC emission rates in the aerobic treatment process, the associated health risks were limited due to the low VOC concentrations in the gas phase, which were likely attributed to the strong mixing and dilution with fresh air by aeration. Amongst the VOCs investigated, benzene was the VOC with both a relatively high emission rate and health risk, while trichloroethylene possessed a high emission rate but the lowest health risk. Without strong interfacial aeration and turbulence between the water and atmosphere, the effects of treatment technology and seasonal variation on the health risks might be connected to the VOC emission rates, while the effect of VOC species depended considerably on the respective cancer slope factors and reference concentrations; the employment of aeration provided a different conclusion in which the emission rates were enhanced without a significant increase in the related cancer risks. These findings can provide insight into future health risk management and

  15. Quantification of Methane and VOC Emissions from Natural Gas Production in Two Basins with High Ozone Events

    Science.gov (United States)

    Edie, R.; Robertson, A.; Snare, D.; Soltis, J.; Field, R. A.; Murphy, S. M.

    2015-12-01

    Since 2005, the Uintah Basin of Utah and the Upper Green River Basin of Wyoming frequently exceeded the EPA 8-hour allowable ozone level of 75 ppb, spurring interest in volatile organic compounds (VOCs) emitted during oil and gas production. Debate continues over which stage of production (drilling, flowback, normal production, transmission, etc.) is the most prevalent VOC source. In this study, we quantify emissions from normal production on well pads by using the EPA-developed Other Test Method 33a. This methodology combines ground-based measurements of fugitive emissions with 3-D wind data to calculate the methane and VOC emission fluxes from a point source. VOC fluxes are traditionally estimated by gathering a canister of air during a methane flux measurement. The methane:VOC ratio of this canister is determined at a later time in the laboratory, and applied to the known methane flux. The University of Wyoming Mobile Laboratory platform is equipped with a Picarro methane analyzer and an Ionicon Proton Transfer Reaction-Time of Flight-Mass Spectrometer, which provide real-time methane and VOC data for each well pad. This independent measurement of methane and VOCs in situ reveals multiple emission sources on one well pad, with varying methane:VOC ratios. Well pad emission estimates of methane, benzene, toluene and xylene for the two basins will be presented. The different emission source VOC profiles and the limitations of real-time and traditional VOC measurement methods will also be discussed.

  16. Source reduction for prevention of methylene chloride hazards: cases from four industrial sectors

    Directory of Open Access Journals (Sweden)

    Ellenbecker Michael J

    2003-07-01

    Full Text Available Abstract Background Source reduction, defined as chemical, equipment and process changes that intervene in an industrial process to eliminate or reduce hazards, has not figured as a front-line strategy for the protection of workers' health. Such initiatives are popular for environmental protection, but their feasibility and effectiveness as an industrial hygiene approach have not been well described. Methods We investigated four cases of source reduction as a hazard prevention strategy in Massachusetts companies that had used methylene chloride, an occupational carcinogen, for cleaning and adhesive thinning. Three cases were retrospective and one was prospective, where the researchers assisted with the source reduction process change. Data were collected using qualitative research methods, including in-depth interviews and site visits. Results Motivated by environmental restrictions, a new worker health standard, and opportunity for productivity improvements, three companies eliminated their use of methylene chloride by utilizing available technologies and drop-in substitutes. Aided by technical assistance from the investigators, a fourth case dramatically reduced its use of methylene chloride via process and chemistry changes. While the companies' evaluations of potential work environment impacts of substitutes were not extensive, and in two cases new potential hazards were introduced, the overall impact of the source reduction strategy was deemed beneficial, both from a worker health and a production standpoint. Conclusion The findings from these four cases suggest that source reduction should be considered potentially feasible and effective for reducing or eliminating the potential hazards of methylene chloride exposure. Especially when faced with a hazard that is both an environmental and worker health concern, companies may chose to change their processes rather than rely on local exhaust ventilation equipment or personal protective

  17. Experiments in the EMRP project KEY-VOCs: Adsorption/desorption effects of VOCs in different tubing materials and preparation and analysis of a zero gas

    Science.gov (United States)

    Englert, Jennifer; Claude, Anja; Kubistin, Dagmar; Tensing, Erasmus; Michl, Katja; Plass-Duelmer, Christian

    2017-04-01

    Atmospheric chemistry and composition are influenced by volatile organic compounds (VOCs) emitted from natural and anthropogenic sources. Due to their toxicity and their crucial role in ozone and aerosol formation VOCs impact air quality and climate change and high quality observations are demanded. The European Metrology Research Programme (EMRP) project KEY-VOCs has targeted the improvement of VOC measurement capabilities with the focus on VOCs relevant for indoor air as well as for air quality and climate monitoring programmes. One major uncertainty is the influence of surface effects of the measurement devices. By developing a test system the adsorption/desorption effects of certain VOCs can be systematically examined. Different tubing materials e.g. stainless steel and PFA were analysed with the oxygenated VOC methanol and results of these experiments will be presented. In air quality monitoring very low levels of VOCs have to be measured. Purified air or nitrogen is widely used as a zero gas to characterize measurement systems and procedures as well as for instrument calibration. A high quality zero gas is an important contributor to the quality of the measurements and generally achieved by using state-of-the-art purification technologies. The efficiency of several air purifiers was assessed and the results have been analysed.

  18. Selective reduction of condensed N-heterocycles using water as a solvent and a hydrogen source.

    Science.gov (United States)

    Cho, Hyejin; Török, Fanni; Török, Béla

    2013-02-21

    The reduction of unprotected indoles and quinolines is described using water as a hydrogen source. The method is based on the application of a RANEY® type Ni-Al alloy in an aqueous medium. During the reaction the Al content of the alloy, used as reductants, reacts with water in situ providing hydrogen and a RANEY® Ni catalyst, thus the alloy serves as a hydrogen generator as well as a hydrogenation catalyst. The simplicity and efficacy of the method are illustrated by the selective reduction of a variety of substituted indoles and quinolines to indolines and tetrahydroquinolines, respectively.

  19. Flux and Mass Reduction Resulting from ZVIClay Remediation of a PCE DNAPL Source Zone

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Kjeldsen, Peter; Riis, C.

    2010-01-01

    of bentonite clay. The degradation of PCE in the treated source area and the development in the downstream flux of chlorinated compounds have been monitored in six sampling campaigns. A PCE half-life of 50 days and a reduction of the average concentration of PCE of more than 99% were found during the first...

  20. PARAMETRIC EVALUATION OF VOC CONVERSION VIA CATALYTIC INCINERATION

    Directory of Open Access Journals (Sweden)

    Kaskantzis Neto G.

    1997-01-01

    Full Text Available Abstract - A pilot-scale catalytic incineration system was used to investigate the effectiveness of catalytic incineration as a means of reducing volatile organic compound (VOC air pollutants. The objectives of the study were: 1 to investigate the effects of operating and design variables on the reduction efficiency of VOCs; and 2 to evaluate reduction efficiencies for specific compounds in different chemical classes. The study results verified that the following factors affect the catalyst performance: inlet temperature, space velocity, compound type, and compound inlet concentration. Tests showed that reduction efficiencies exceeding 98% were possible, given sufficiently high inlet gas temperatures for the following classes of compounds: alcohols, acetates, ketones, hydrocarbons, and aromatics

  1. SPECIATED VOC EMISSIONS FROM MODERN GDI LIGHT ...

    Science.gov (United States)

    Chassis dynamometer emissions testing was conducted to characterize speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs) and ozone precursors, in exhaust emissions from three modern gasoline direct injection (GDI) light-duty vehicles. Each GDI vehicle tested in this study utilized slightly different fuel injection technology: Vehicle 1 used a 2.4 liter, naturally aspirated, wall-guided GDI; Vehicle 2 used a 1.8 liter, turbocharged GDI engine; Vehicle 3 used a 1.5 liter, turbocharged, spray-guided GDI engine. Vehicle testing was conducted in a temperature controlled chassis dynamometer test cell at 22 °C over the EPA Federal Test Procedure (FTP) and a portion of the Supplemental FTP (SFTP). The FTP was conducted as a three phase cycle with a cold start, hot transient, and warm start phase (also known as the FTP-75 driving cycle). The SFTP consisted of the US06 driving cycle (conducted without the vehicle’s air conditioning on), which provides a more aggressive driving pattern than the FTP. The vehicles operated on 10 percent ethanol blended gasoline (E10). VOC emissions from diluted vehicle exhaust were sampled over each FTP phase and over the Supplemental FTP with SUMMA canisters for EPA Method TO-15 analysis and with DNPH cartridges for carbonyl analysis by EPA Method TO-11A. This presentation will report the impact of driving cycle and GDI technology on speciated MSAT emissions. MSAT emission rates will be compared

  2. Microbial community structure and function of nitrobenzene reduction biocathode in response to carbon source switchover.

    Science.gov (United States)

    Liang, Bin; Cheng, Haoyi; Van Nostrand, Joy D; Ma, Jincai; Yu, Hao; Kong, Deyong; Liu, Wenzong; Ren, Nanqi; Wu, Liyou; Wang, Aijie; Lee, Duu-Jong; Zhou, Jizhong

    2014-05-01

    The stress of poised cathode potential condition and carbon source switchover for functional biocathode microbial community influences is poorly understood. Using high-throughput functional gene array (GeoChip v4.2) and Illumina 16S rRNA gene MiSeq sequencing, we investigated the phylogenetic and functional microbial community of the initial inoculum and biocathode for bioelectrochemical reduction of nitrobenzene to less toxic aniline in response to carbon source switchover (from organic glucose to inorganic bicarbonate). Selective transformation of nitrobenzene to aniline maintained in the bicarbonate fed biocathode although nitrobenzene reduction rate and aniline formation rate were significantly decreased compared to those of the glucose-fed biocathode. When the electrical circuit of the glucose-fed biocathode was disconnected, both rates of nitrobenzene reduction and of aniline formation were markedly decreased, confirming the essential role of an applied electric field for the enhancement of nitrobenzene reduction. The stress of poised cathode potential condition led to clear succession of microbial communities from the initial inoculum to biocathode and the carbon source switchover obviously changed the microbial community structure of biocathode. Most of the dominant genera were capable of reducing nitroaromatics to the corresponding aromatic amines regardless of the performance mode. Heterotrophic Enterococcus was dominant in the glucose-fed biocathode while autotrophic Paracoccus and Variovorax were dominant in the bicarbonate-fed biocathode. Relatively higher intensity of diverse multi-heme cytochrome c (putatively involved in electrons transfer) and carbon fixation genes was observed in the biocarbonate-fed biocathode, likely met the requirement of the energy conservation and maintained the nitrobenzene selective reduction capability after carbon source switchover. Extracellular pilin, which are important for biofilm formation and potential conductivity

  3. Air exchange rates and migration of VOCs in basements and residences

    Science.gov (United States)

    Du, Liuliu; Batterman, Stuart; Godwin, Christopher; Rowe, Zachary; Chin, Jo-Yu

    2015-01-01

    Basements can influence indoor air quality by affecting air exchange rates (AERs) and by the presence of emission sources of volatile organic compounds (VOCs) and other pollutants. We characterized VOC levels, AERs and interzonal flows between basements and occupied spaces in 74 residences in Detroit, Michigan. Flows were measured using a steady-state multi-tracer system, and 7-day VOC measurements were collected using passive samplers in both living areas and basements. A walkthrough survey/inspection was conducted in each residence. AERs in residences and basements averaged 0.51 and 1.52 h−1, respectively, and had strong and opposite seasonal trends, e.g., AERs were highest in residences during the summer, and highest in basements during the winter. Air flows from basements to occupied spaces also varied seasonally. VOC concentration distributions were right-skewed, e.g., 90th percentile benzene, toluene, naphthalene and limonene concentrations were 4.0, 19.1, 20.3 and 51.0 μg m−3, respectively; maximum concentrations were 54, 888, 1117 and 134 μg m−3. Identified VOC sources in basements included solvents, household cleaners, air fresheners, smoking, and gasoline-powered equipment. The number and type of potential VOC sources found in basements are significant and problematic, and may warrant advisories regarding the storage and use of potentially strong VOCs sources in basements. PMID:25601281

  4. Pollution characteristic of VOCs of ambient air in winter and spring in Shijiazhuang City

    Directory of Open Access Journals (Sweden)

    Qing CHANG

    2015-06-01

    Full Text Available In order to further explore the pollution characteristics of volatile organic compounds in ambient air in winter and spring in Shijiazhuang City, the pollution characteristics of 62 volatile organic compounds (VOCs, monthly and quarterly variation, the correlation between VOCs and PM2.5, and the main sources of VOCs are investigated by using EPA TO-15 method. It shows that 40 organic compounds of the 64 VOCs have been quantitatively determined in winter and spring in the city, which are mainly acetone, benzene, carbon tetrachloride, dichloromethane, toluene, ethyl acetate, etc.. In the no-quantitatively determined components, higher ethanol, butyl acetate, butane etc. are detected. The VOCs concentration has positive correlation with the PM2.5 concentration during haze days.

  5. Allelopatic Potential of Dittrichia viscosa (L. W. Greuter Mediated by VOCs: A Physiological and Metabolomic Approach.

    Directory of Open Access Journals (Sweden)

    Fabrizio Araniti

    Full Text Available Dittrichia viscosa (L. W. Greuter is a pioneer species belonging to the Compositae family. It is widespread in the Mediterranean basin, where it is considered invasive. It is a source of secondary metabolites, playing an important ecological role. D. viscosa plant extracts showed a phytotoxic activity on several physiological processes of different species. In the current study, the allelopathic potential of D. viscosa VOCs, released by its foliage, was evaluated on seed germination and root growth of lettuce. The VOCs effect was also studied on lettuce adult plants in microcosm systems, which better mimicked the open field conditions. D. viscosa VOCs inhibited both seed germination and root growth of lettuce. The VOCs composition revealed a large presence of terpenoids, responsible of the effects observed. Moreover, D. viscosa VOCs caused an alteration on plant water status accompanied by oxidative damages and photoinhibition on lettuce adult plants.

  6. Allelopatic Potential of Dittrichia viscosa (L.) W. Greuter Mediated by VOCs: A Physiological and Metabolomic Approach

    Science.gov (United States)

    Lupini, Antonio; Sunseri, Francesco; Abenavoli, Maria Rosa

    2017-01-01

    Dittrichia viscosa (L.) W. Greuter is a pioneer species belonging to the Compositae family. It is widespread in the Mediterranean basin, where it is considered invasive. It is a source of secondary metabolites, playing an important ecological role. D. viscosa plant extracts showed a phytotoxic activity on several physiological processes of different species. In the current study, the allelopathic potential of D. viscosa VOCs, released by its foliage, was evaluated on seed germination and root growth of lettuce. The VOCs effect was also studied on lettuce adult plants in microcosm systems, which better mimicked the open field conditions. D. viscosa VOCs inhibited both seed germination and root growth of lettuce. The VOCs composition revealed a large presence of terpenoids, responsible of the effects observed. Moreover, D. viscosa VOCs caused an alteration on plant water status accompanied by oxidative damages and photoinhibition on lettuce adult plants. PMID:28085959

  7. Reduction at the source of household wastes: why not trying the inciting tariffing?; La reduction a la source des dechets menagers: pourquoi ne pas essayer la tarification incitative?

    Energy Technology Data Exchange (ETDEWEB)

    Glachant, M.

    2002-11-01

    This article discusses how the existing financing tools of the household wastes management implemented in France can be changed to become inciting tools for the reduction of the volume of wastes at the source. It comprises 5 parts: the first part presents the present day way of financing of the public utility of household wastes in France and discusses its (very modest) inciting effect. In the next two parts the possible modalities to make it more inciting are discussed. These parts stresses on two questions: is it better to charge the upstream producers via contributions to chartered companies or to charge the downstream households via volume- or weight-proportional fees? How much should they pay? Then some experiences of inciting tariffing are briefly reviewed: the Duales German system of upstream charging and the US and Dutch downstream charging systems. (J.S.)

  8. Field observations of volatile organic compound (VOC) exchange in red oaks

    Science.gov (United States)

    Cappellin, Luca; Algarra Alarcon, Alberto; Herdlinger-Blatt, Irina; Sanchez, Juaquin; Biasioli, Franco; Martin, Scot T.; Loreto, Francesco; McKinney, Karena A.

    2017-03-01

    Volatile organic compounds (VOCs) emitted by forests strongly affect the chemical composition of the atmosphere. While the emission of isoprenoids has been largely characterized, forests also exchange many oxygenated VOCs (oVOCs), including methanol, acetone, methyl ethyl ketone (MEK), and acetaldehyde, which are less well understood. We monitored total branch-level exchange of VOCs of a strong isoprene emitter (Quercus rubra L.) in a mixed forest in New England, where canopy-level fluxes of VOCs had been previously measured. We report daily exchange of several oVOCs and investigated unknown sources and sinks, finding several novel insights. In particular, we found that emission of MEK is linked to uptake of methyl vinyl ketone (MVK), a product of isoprene oxidation. The link was confirmed by corollary experiments proving in vivo detoxification of MVK, which is harmful to plants. Comparison of MEK, MVK, and isoprene fluxes provided an indirect indication of within-plant isoprene oxidation. Furthermore, besides confirming bidirectional exchange of acetaldehyde, we also report for the first time direct evidence of benzaldehyde bidirectional exchange in forest plants. Net emission or deposition of benzaldehyde was found in different periods of measurements, indicating an unknown foliar sink that may influence atmospheric concentrations. Other VOCs, including methanol, acetone, and monoterpenes, showed clear daily emission trends but no deposition. Measured VOC emission and deposition rates were generally consistent with their ecosystem-scale flux measurements at a nearby site.

  9. Emission of VOC Compounds from Ta-Shan Chemical Industrial Park in Middle China

    Science.gov (United States)

    Li, Jian; Xie, Chunjuan; Cao, Qun; Yan, Liushui; Zhong, Jiaochan

    2017-03-01

    VOCs emission from a Ta-Shan Chemical Industrial Park in January 1-8, 2014 and summer (July 16-20, 2014) have been studied in this paper. VOCs were collected by the stainlessteel canisters and following pre-concentrate and analyzing by GC/MSD. The results showed that a total of 33 VOC species in winter samplers and 41 VOC species in summer samplers were detected. Among the 41 VOC species detected in the winter and summer samplers, 1-Butene and Ethane were the two most abundant compounds. Their highest average mean concentrations were 6013±1758 and 3188±1025 pptv in summer (contributed more than 12.5% and 4.8 % of the total VOC concentrations), and about 5895±1246 and 2763±789 pptv in winter (contributed more than12.9% and 7.8% of the total VOC concentrations), respectively. In winter, stack emission was found to be the main souce of VOCs emission, while in summer, fugitive emission become the primary source.

  10. Volatile organic compounds released from Microcystis flos-aquae under nitrogen sources and their toxic effects on Chlorella vulgaris.

    Science.gov (United States)

    Xu, Qinghuan; Yang, Lin; Yang, Wangting; Bai, Yan; Hou, Ping; Zhao, Jingxian; Zhou, Lv; Zuo, Zhaojiang

    2017-01-01

    Eutrophication promotes massive growth of cyanobacteria and algal blooms, which can poison other algae and reduce biodiversity. To investigate the differences in multiple nitrogen (N) sources in eutrophicated water on the emission of volatile organic compounds (VOCs) from cyanobacteria, and their toxic effects on other algal growth, we analyzed VOCs emitted from Microcystis flos-aquae with different types and concentrations of nitrogen, and determined the effects under Normal-N and Non-N conditions on Chlorella vulgaris. M. flos-aquae released 27, 22, 20, 27, 19, 25 and 17 compounds, respectively, with NaNO3, NaNO2, NH4Cl, urea, Ser, Lys and Arg as the sole N source. With the reduction in N amount, the emission of VOCs was increased markedly, and the most VOCs were found under Non-N condition. C. vulgaris cell propagation, photosynthetic pigment and Fv/Fm declined significantly following exposure to M. flos-aquae VOCs under Non-N condition, but not under Normal-N condition. When C. vulgaris cells were treated with two terpenoids, eucalyptol and limonene, the inhibitory effects were enhanced with increasing concentrations. Therefore, multiple N sources in eutrophicated water induce different VOC emissions from cyanobacteria, and reduction in N can cause nutrient competition, which can result in emissions of more VOCs. Those VOCs released from M. flos-aquae cells under Non-N for nutrient competition can inhibit other algal growth. Among those VOCs, eucalyptol and limonene are the major toxic agents. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Modeling and analysis of secondary sources coupling for active sound field reduction in confined spaces

    Science.gov (United States)

    Montazeri, Allahyar; Taylor, C. James

    2017-10-01

    This article addresses the coupling of acoustic secondary sources in a confined space in a sound field reduction framework. By considering the coupling of sources in a rectangular enclosure, the set of coupled equations governing its acoustical behavior are solved. The model obtained in this way is used to analyze the behavior of multi-input multi-output (MIMO) active sound field control (ASC) systems, where the coupling of sources cannot be neglected. In particular, the article develops the analytical results to analyze the effect of coupling of an array of secondary sources on the sound pressure levels inside an enclosure, when an array of microphones is used to capture the acoustic characteristics of the enclosure. The results are supported by extensive numerical simulations showing how coupling of loudspeakers through acoustic modes of the enclosure will change the strength and hence the driving voltage signal applied to the secondary loudspeakers. The practical significance of this model is to provide a better insight on the performance of the sound reproduction/reduction systems in confined spaces when an array of loudspeakers and microphones are placed in a fraction of wavelength of the excitation signal to reduce/reproduce the sound field. This is of particular importance because the interaction of different sources affects their radiation impedance depending on the electromechanical properties of the loudspeakers.

  12. Effect of outside air ventilation rate on VOC concentrations and emissions in a call center

    Energy Technology Data Exchange (ETDEWEB)

    Hodgson, A.T.; Faulkner, D.; Sullivan, D.P.; DiBartolomeo, D.L.; Russell, M.L.; Fisk, W.J.

    2002-01-01

    A study of the relationship between outside air ventilation rate and concentrations of VOCs generated indoors was conducted in a call center. Ventilation rates were manipulated in the building's four air handling units (AHUs). Concentrations of VOCs in the AHU returns were measured on 7 days during a 13-week period. Indoor minus outdoor concentrations and emission factors were calculated. The emission factor data was subjected to principal component analysis to identify groups of co-varying compounds based on source type. One vector represented emissions of solvents from cleaning products. Another vector identified occupant sources. Direct relationships between ventilation rate and concentrations were not observed for most of the abundant VOCs. This result emphasizes the importance of source control measures for limiting VOC concentrations in buildings.

  13. In Situ NAPL Modification for Contaminant Source-Zone Passivation, Mass Flux Reduction, and Remediation

    Science.gov (United States)

    Mateas, D. J.; Tick, G.; Carroll, K. C.

    2016-12-01

    A remediation method was developed to reduce the aqueous solubility and mass-flux of target NAPL contaminants through the in-situ creation of a NAPL mixture source-zone. This method was tested in the laboratory using equilibrium batch tests and two-dimensional flow-cell experiments. The creation of two different NAPL mixture source zones were tested in which 1) volumes of relatively insoluble n-hexadecane (HEX) or vegetable oil (VO) were injected into a trichloroethene (TCE) contaminant source-zone; and 2) pre-determined HEX-TCE and VO-TCE mixture ratio source zones were emplaced into the flow cell prior to water flushing. NAPL-aqueous phase batch tests were conducted prior to the flow-cell experiments to evaluate the effects of various NAPL mixture ratios on equilibrium aqueous-phase concentrations of TCE and toluene (TOL) and to design optimal NAPL (HEX or VO) injection volumes for the flow-cell experiments. Uniform NAPL mixture source-zones were able to quickly decrease contaminant mass-flux, as demonstrated by the emplaced source-zone experiments. The success of the HEX and VO injections to also decrease mass flux was dependent on the ability of these injectants to homogeneously mix with TCE source-zone. Upon injection, both HEX and VO migrated away from the source-zone, to some extent. However, the lack of a steady-state dissolution phase and the inefficient mass-flux-reduction/mass-removal behavior produced after VO injection suggest that VO was more effective than HEX for mixing and partitioning within the source-zone region to form a more homogeneous NAPL mixture with TCE. VO appears to be a promising source-zone injectant-NAPL due to its negligible long-term toxicity and lower mobilization potential.

  14. Concentrations and flux measurements of volatile organic compounds (VOC) in boreal forest soil

    Science.gov (United States)

    Mäki, Mari; Aaltonen, Hermanni; Heinonsalo, Jussi; Hellén, Heidi; Pumpanen, Jukka; Bäck, Jaana

    2017-04-01

    Volatile organic compounds (VOC) impact soil processes as VOCs transmit signals between roots and rhizosphere (Ditengou et al., 2015), VOCs can regulate microbial activity (Asensio et al., 2012), and VOCs can also promote root growth (Hung et al., 2012). Belowground concentrations of VOCs have not been measured in situ and for this reason, knowledge of how different soil organisms such as roots, rhizosphere and decomposers contribute to VOC production is limited. The aim of this study was to determine and quantify VOC fluxes and concentrations of different horizons from boreal forest soil. The VOC concentrations and fluxes were measured from Scots pine (Pinus sylvestris) forest soil at the SMEAR II station in southern Finland from 21th of April to 2nd of December in 2016. VOC fluxes were measured using dynamic (flow-through) chambers from five soil collars placed on five different locations. VOC concentrations were also measured in each location from four different soil horizons with the measurement depth 1-107 cm. VOCs were collected from underground gas collectors into the Tenax-Carbopack-B adsorbent tubes using portable pumps ( 100 ml min-1). The VOC concentrations and fluxes of isoprene, 11 monoterpenes, 13 sesquiterpenes and different oxygenated VOCs were measured. Sample tubes were analyzed using thermal desorption-gas chromatograph-mass spectrometry (TD-GC-MS). Soil temperature and soil water content were continuously monitored for each soil horizon. Our preliminary results show that the primary source of VOCs is organic soil layer and the contribution of mineral soil to the VOC formation is minor. VOC fluxes and concentrations were dominated by monoterpenes such as α-pinene, camphene, β-pinene, and Δ3-carene. Monoterpene concentration is almost 10-fold in organic soil compared to the deeper soil layers. However, the highest VOC fluxes on the soil surface were measured in October, whereas the monoterpene concentrations in organic soil were highest in July

  15. The potentional of renewable energy sources for greenhouse gases emissions reduction in Macedonia

    Directory of Open Access Journals (Sweden)

    Dedinec Aleksandar

    2012-01-01

    Full Text Available As European Union (EU candidate country, Macedonia is in the process of adoption of the EU strategic energy policies, harmonization of the national legislation with the EU legislation and defining the respective national goals. In this regard, the government has recently adopted a National Strategy for Utilization of Renewable Energy Sources (RES, prepared by ICEIM-MANU. The main goal of this paper is to assess the potential for greenhouse gases (GHG emissions reduction by implementation of 21%-RES-scenarios from the Strategy. The corresponding emissions reduction is calculated against the baseline (reference scenario developed within the Second National Communication on Climate Change. Furthermore, all potential RES technologies are analyzed from economic aspect and combined in a form of emissions reduction cost curve, displaying the total marginal cost of the GHG emissions reduction by RES. Finally, on the bases of the environmental and economic effectiveness of the considered RES technologies, as well as taking into account the country specific barriers, the priority actions for GHG emissions reduction are identified.

  16. [Volatile organic compounds (VOCs) emitted from large furniture].

    Science.gov (United States)

    Tanaka-Kagawa, Toshiko; Furuta, Mitsuko; Shibatsuji, Masayoshi; Jinno, Hideto; Nishimura, Tetsuji

    2011-01-01

    Indoor air pollution by volatile organic compounds (VOCs), which may cause a hazardous influence on human being such as sick building (sick house) syndrome, has become a serious problem. In this study, VOCs emitted from nine pieces of home furniture, three sets of dining tables, three sets of chest of drawers and three sofas, were analyzed as potential sources of indoor air pollution by large chamber test method (JIS A 1911). Based on the emission rates of total VOC (TVOC), the impacts on the indoor TVOC was estimated by the sample model with a volume of 20 m3 and ventilation frequency of 0.5 times/h. The estimated TVOC increment values were exceeded the provisional target value for indoor air (400 microg/m3) in three sets of dining tables, one set of chest of drawer and one sofa. The estimated increment of formaldehyde were exceeded the guideline value (100 microg/m3) in one set of dining table, two sets of chest of drawers and one sofa. These results revealed that VOC emissions from furniture may influence significantly indoor air quality. Also, in this study, to establish the alternative method for large chamber test methods, emission rates from representative three parts of furniture unit were evaluated using the small chamber and emission rate from full-sized furniture was predicted. Emission rates of TVOC and formaldehyde predicted by small chamber test were 3-46% and 6-252% of the data obtained using large chamber test, respectively.

  17. [Pollution characteristics and ozone formation potential of ambient VOCs in winter and spring in Xiamen].

    Science.gov (United States)

    Xu, Hui; Zhang, Han; Xing, Zhen-yu; Deng, Jun-jun

    2015-01-01

    Air samples were collected at urban and rural sites in Xiamen from January to April 2014. The concentrations of 48 ambient volatile organic compounds (VOC) species were measured by the method of cryogenic pre-concentrator and gas chromatography-mass spectrometry (GC/MS). The ozone formation potential (OFP) of VOCs was also calculated with the method of maximum incremental reactivity (MIR). The results showed that the average mixing ratios of VOCs in winter were 11.13 x 10(-9) and 7.17 x 10(-9) at urban and rural sites, respectively, and those in spring were 24.88 x 10(-9) and 11.27 x 10(-9) at urban and rural sites, respectively. At both sites, alkanes contributed the most to VOCs, followed by aromatics and alkenes. The ratios of B/T showed that vehicle and solvent evaporation were the main sources of VOCs at urban site. While at rural site, transport of anthropogenic sources was another important source of VOCs besides local biomass emissions. Ten main components including propene, n-butane, i-butane, n-pentane, i-pentane, n-hexane, benzene, toluene, ethylbenzene and m/p-xylene accounted for 61.57% and 45.83% of total VOCs at urban and rural sites in winter, respectively, and 62.83% and 53.74% at urban and rural sites in spring, respectively. Aromatics contributed the most to total OFP, followed by alkenes. Alkanes contributed the least to OFP with the highest concentration. C3, C4 alkenes and aromatics were found to be the more reactive species with relatively high contributions to ozone formation in Xiamen. Comparing the average MIR of VOCs at the two sites, it was found that the reactivity of VOCs at rural site was higher than that at urban site.

  18. Development of new VOC exposure metrics and their relationship to ''Sick Building Syndrome'' symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Ten Brinke, JoAnn [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab., Berkeley, CA (United States)

    1995-08-01

    Volatile organic compounds (VOCs) are suspected to contribute significantly to ''Sick Building Syndrome'' (SBS), a complex of subchronic symptoms that occurs during and in general decreases away from occupancy of the building in question. A new approach takes into account individual VOC potencies, as well as the highly correlated nature of the complex VOC mixtures found indoors. The new VOC metrics are statistically significant predictors of symptom outcomes from the California Healthy Buildings Study data. Multivariate logistic regression analyses were used to test the hypothesis that a summary measure of the VOC mixture, other risk factors, and covariates for each worker will lead to better prediction of symptom outcome. VOC metrics based on animal irritancy measures and principal component analysis had the most influence in the prediction of eye, dermal, and nasal symptoms. After adjustment, a water-based paints and solvents source was found to be associated with dermal and eye irritation. The more typical VOC exposure metrics used in prior analyses were not useful in symptom prediction in the adjusted model (total VOC (TVOC), or sum of individually identified VOCsVOCi)). Also not useful were three other VOC metrics that took into account potency, but did not adjust for the highly correlated nature of the data set, or the presence of VOCs that were not measured. High TVOC values (2--7 mg m-3) due to the presence of liquid-process photocopiers observed in several study spaces significantly influenced symptoms. Analyses without the high TVOC values reduced, but did not eliminate the ability of the VOC exposure metric based on irritancy and principal component analysis to explain symptom outcome.

  19. Organic liquids storage tanks volatile organic compounds (VOCS) emissions dispersion and risk assessment in developing countries: the case of Dar-es-Salaam City, Tanzania.

    Science.gov (United States)

    Jackson, Msafiri M

    2006-05-01

    The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage tanks companies in Dar-es-Salaam City Tanzania has been done by using US EPA standard regulatory storage tanks emission model (TANKS 4.9b). Total VOCs atmospheric emission has been established to be 853.20 metric tones/yr. It has been established further that petrol storage tanks contribute about 87% of total VOCs emitted, while tanks for other refined products and crude oil were emitting 10% and 3% of VOCs respectively. Of the eight sources (companies), the highest emission value from a single source was 233,222.94 kg/yr and the lowest single source emission value was 6881.87 kg/yr. The total VOCs emissions estimated for each of the eight sources were found to be higher than the standard level of 40,000 kg/yr per source for minor source according to US EPA except for two sources, which were emitting VOCs below the standard level. The annual emissions per single source for each of the VOCs were found to be below the US EPA emissions standard which is 2,000 kg/yr in all companies except the emission of hexane from company F1 which was slightly higher than the standard. The type of tanks used seems to significantly influence the emission rate. Vertical fixed roof tanks (VFRT) emit a lot more than externally floating roof tanks (EFRT) and internally floating roof tanks (IFRT). The use of IFRT and EFRT should be encouraged especially for storage of petrol which had highest atmospheric emission contribution. Model predicted atmospheric emissions are less than annual losses measured by companies in all the eight sources. It is possible that there are other routes for losses beside atmospheric emissions. It is therefore important that waste reduction efforts in these companies are directed not only to reducing atmospheric emissions, but also prevention of the spillage and leakage of stored liquid and curbing of the frequently reported illegal siphoning of stored products

  20. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

    Science.gov (United States)

    Baek, Sung-Ok; Suvarapu, Lakshmi Narayana; Seo, Young-Kyo

    2015-01-01

    This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs) including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory role in improving

  1. Occurrence and Concentrations of Toxic VOCs in the Ambient Air of Gumi, an Electronics-Industrial City in Korea

    Directory of Open Access Journals (Sweden)

    Sung-Ok Baek

    2015-08-01

    Full Text Available This study was carried out to characterize the occurrence and concentrations of a variety of volatile organic compounds (VOCs including aliphatic, aromatic, halogenated, nitrogenous, and carbonyl compounds, in the ambient air of Gumi City, where a large number of electronics industries are found. Two field monitoring campaigns were conducted for a one year period in 2003/2004 and 2010/2011 at several sampling sites in the city, representing industrial, residential and commercial areas. More than 80 individual compounds were determined in this study, and important compounds were then identified according to their abundance, ubiquity and toxicity. The monitoring data revealed toluene, trichloroethylene and acetaldehyde to be the most significant air toxics in the city, and their major sources were mainly industrial activities. On the other hand, there was no clear evidence of an industrial impact on the concentrations of benzene and formaldehyde in the ambient air of the city. Overall, seasonal variations were not as distinct as locational variations in the VOCs concentrations, whereas the within-day variations showed a typical pattern of urban air pollution, i.e., increase in the morning, decrease in the afternoon, and an increase again in the evening. Considerable decreases in the concentrations of VOCs from 2003 to 2011 were observed. The reductions in the ambient concentrations were confirmed further by the Korean PRTR data in industrial emissions within the city. Significant decreases in the concentrations of benzene and acetaldehyde were also noted, whereas formaldehyde appeared to be almost constant between the both campaigns. The decreased trends in the ambient levels were attributed not only to the stricter regulations for VOCs in Korea, but also to the voluntary agreement of major companies to reduce the use of organic solvents. In addition, a site planning project for an eco-friendly industrial complex is believed to play a contributory

  2. Sorbent-Based Gas Phase Air Cleaning for VOCs in CommercialBuildings

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William J.

    2006-05-01

    This paper provides a review of current knowledge about the suitability of sorbent-based air cleaning for removing volatile organic compounds (VOCs) from the air in commercial buildings as needed to enable reductions in ventilation rates and associated energy savings. The fundamental principles of sorbent air cleaning are introduced, criteria are suggested for sorbent systems that can counteract indoor VOC concentration increases from reduced ventilation, major findings from research on sorbent performance for this application are summarized, novel sorbent technologies are described, and related priority research needs are identified. Major conclusions include: sorbent systems can remove a broad range of VOCs with moderate to high efficiency, sorbent technologies perform effectively when challenged with VOCs at the low concentrations present indoors, and there is a large uncertainty about the lifetime and associated costs of sorbent air cleaning systems when used in commercial buildings for indoor VOC control. Suggested priority research includes: experiments to determine sorbent system VOC removal efficiencies and lifetimes considering the broad range and low concentration of VOCs indoors; evaluations of in-situ regeneration of sorbents; and an updated analysis of the cost of sorbent air cleaning relative to the cost of ventilation.

  3. CAN SORBENT-BASED GAS PHASE AIR CLEANING FOR VOCS SUBSTITUTE FOR VENTILATION IN COMMERCIAL BUILDINGS?

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, William; Fisk, William J.

    2007-08-01

    This paper reviews current knowledge about the suitability of sorbent-based air cleaning for removing volatile organic compounds (VOCs) from the air in commercial buildings, as needed to enable reductions in ventilation rates and associated energy savings. The principles of sorbent air cleaning are introduced, criteria are suggested for sorbent systems that can counteract indoor VOC concentration increases from reduced ventilation, major findings from research on sorbent performance for this application are summarized, and related priority research needs are identified. Major conclusions include: sorbent systems can remove a broad range of VOCs with moderate to high efficiency, sorbent technologies perform effectively when challenged with VOCs at the low concentrations present indoors, and there is a large uncertainty about the lifetime and associated costs of sorbent air cleaning systems when used in commercial buildings for indoor VOC control. Suggested priority research includes: experiments to determine sorbent system VOC removal efficiencies and lifetimes considering the broad range and low concentration of VOCs indoors; evaluations of in-situ regeneration of sorbents; and an updated analysis of the cost of sorbent air cleaning relative to the cost of ventilation.

  4. Volatile Organic Compounds (VOCs in Conventional and High Performance School Buildings in the U.S.

    Directory of Open Access Journals (Sweden)

    Lexuan Zhong

    2017-01-01

    Full Text Available Exposure to volatile organic compounds (VOCs has been an indoor environmental quality (IEQ concern in schools and other buildings for many years. Newer designs, construction practices and building materials for “green” buildings and the use of “environmentally friendly” products have the promise of lowering chemical exposure. This study examines VOCs and IEQ parameters in 144 classrooms in 37 conventional and high performance elementary schools in the U.S. with the objectives of providing a comprehensive analysis and updating the literature. Tested schools were built or renovated in the past 15 years, and included comparable numbers of conventional, Energy Star, and Leadership in Energy and Environmental Design (LEED-certified buildings. Indoor and outdoor VOC samples were collected and analyzed by thermal desorption, gas chromatography and mass spectroscopy for 94 compounds. Aromatics, alkanes and terpenes were the major compound groups detected. Most VOCs had mean concentrations below 5 µg/m3, and most indoor/outdoor concentration ratios ranged from one to 10. For 16 VOCs, the within-school variance of concentrations exceeded that between schools and, overall, no major differences in VOC concentrations were found between conventional and high performance buildings. While VOC concentrations have declined from levels measured in earlier decades, opportunities remain to improve indoor air quality (IAQ by limiting emissions from building-related sources and by increasing ventilation rates.

  5. Volatile Organic Compounds (VOCs) in Conventional and High Performance School Buildings in the U.S.

    Science.gov (United States)

    Zhong, Lexuan; Su, Feng-Chiao; Batterman, Stuart

    2017-01-21

    Exposure to volatile organic compounds (VOCs) has been an indoor environmental quality (IEQ) concern in schools and other buildings for many years. Newer designs, construction practices and building materials for "green" buildings and the use of "environmentally friendly" products have the promise of lowering chemical exposure. This study examines VOCs and IEQ parameters in 144 classrooms in 37 conventional and high performance elementary schools in the U.S. with the objectives of providing a comprehensive analysis and updating the literature. Tested schools were built or renovated in the past 15 years, and included comparable numbers of conventional, Energy Star, and Leadership in Energy and Environmental Design (LEED)-certified buildings. Indoor and outdoor VOC samples were collected and analyzed by thermal desorption, gas chromatography and mass spectroscopy for 94 compounds. Aromatics, alkanes and terpenes were the major compound groups detected. Most VOCs had mean concentrations below 5 µg/m³, and most indoor/outdoor concentration ratios ranged from one to 10. For 16 VOCs, the within-school variance of concentrations exceeded that between schools and, overall, no major differences in VOC concentrations were found between conventional and high performance buildings. While VOC concentrations have declined from levels measured in earlier decades, opportunities remain to improve indoor air quality (IAQ) by limiting emissions from building-related sources and by increasing ventilation rates.

  6. VOCs in industrial, urban and suburban neighborhoods—Part 2: Factors affecting indoor and outdoor concentrations

    Science.gov (United States)

    Jia, Chunrong; Batterman, Stuart; Godwin, Christopher

    Many microenvironmental and behavioral factors can affect concentrations of and exposures to volatile organic compounds (VOCs). Identifying these determinants is important to understand exposures and risks, and also to design policies and strategies that minimize concentrations. This study is aimed at determining factors associated with VOC concentrations found indoors in residences and outdoors in ambient air. It utilizes results from a comprehensive field study in which 98 VOCs were measured both inside and outside of 159 residences in three communities in southeast Michigan, USA. Additional measurements included indoor CO 2 concentrations, temperature, relative humidity, building and neighborhood characteristics, and occupant activities, assessed using a questionnaire and comprehensive walkthrough investigation. Factors potentially affecting concentrations were identified using bivariate and multivariate analyses. Outdoors, seasonal and community effects were observed. Indoors, seasonal effects were limited to the urban and industrial communities, largely due to changes in ambient levels. Elevated indoor VOC concentrations were associated with eight sources or activities: the presence of an attached garage; recent renovations; older residences; indoor smoking; less frequent window or door opening; higher CO 2 concentrations; and lower ventilation rates. VOC levels were uninfluenced by building materials (wood vs. brick), flooring type (carpeting vs. wood), stove type (gas or electric), number of occupants, air freshener use, and hobbies involving arts and crafts. Factor analyses identified up to five factors for the ambient VOC measurements, and up to 10 factors for the indoor measurements, which further helped to explain the variability of concentrations and associations between VOCs.

  7. TCP with source traffic shaping (TCP-STS): an approach for network congestion reduction

    Science.gov (United States)

    Elaywe, Ali H.; Kamal, Ahmed E.

    2002-07-01

    The Transmission Control Protocol (TCP), provides flow control functions which are based on the window mechanism. Packet losses are detected by various mechanisms, such as timeouts and duplicate acknowledgements, and are then recovered from using different techniques. A problem that arises with the use of window based mechanisms is that the availability of a large number of credits at the source may cause a source to flood the network with back-to-back packets, which may drive the network into congestion, especially if multiple sources become active at the same time. In this paper we propose a new approach for congestion reduction. The approach works by shaping the traffic at the TCP source, such that the basic TCP flow control mechanism is still preserved, but the packet transmissions are spaced in time in order to prevent a sudden surge of traffic from overflowing the routers' buffers. Simulation results show that this technique can result in an improved network performance, in terms of reduced mean delay, delay variance, and packet dropping ratio.

  8. Estimated Reduction in Cancer Risk due to PAH Exposures If Source Control Measures during the 2008 Beijing Olympics Were Sustained

    National Research Council Canada - National Science Library

    Yuling Jia; Dave Stone; Wentao Wang; Jill Schrlau; Shu Tao; Staci L. Massey Simonich

    2011-01-01

    Background: The 2008 Beijing Olympic Games provided a unique case study to investigate the effect of source control measures on the reduction in air pollution, and associated inhalation cancer risk, in a Chinese megacity. Objectives...

  9. The fractionation factors of stable carbon and hydrogen isotope ratios for VOCs

    Science.gov (United States)

    Kawashima, H.

    2014-12-01

    Volatile organic compounds (VOCs) are important precursors of ozone and secondary organic aerosols in the atmosphere, some of which are carcinogenic, teratogenic, or mutagenic. VOCs in ambient air originate from many sources, including vehicle exhausts, gasoline evaporation, solvent use, natural gas emissions, and industrial processes, and undergo intricate chemical reactions in the atmosphere. To develop efficient air pollution remediation strategies, it is important to clearly identify the emission sources and elucidate the reaction mechanisms in the atmosphere. Recently, stable carbon isotope ratios (δ13C) of VOCs in some sources and ambient air have been measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). In this study, we measured δ13C and stable hydrogen isotope ratios (δD) of atmospheric VOCs by using the gas chromatography/thermal conversion/isotope ratio mass spectrometry coupled with a thermal desorption instrument (TD-GC/TC/IRMS). The wider δD differences between sources were found in comparison with the δ13C studies. Therefore, determining δD values of VOCs in ambient air is potentially useful in identifying VOC sources and their reactive behavior in the atmosphere. However, to elucidate the sources and behavior of atmospheric VOCs more accurately, isotopic fractionation during atmospheric reaction must be considered. In this study, we determined isotopic fractionation of the δ13C and δD values for the atmospheric some VOCs under irradiation conditions. As the results, δ13C for target all VOCs and δD for most VOCs were increasing after irradiation. But, the δD values for both benzene and toluene tended to decrease as irradiation time increased. We also estimated the fractionation factors for benzene and toluene, 1.27 and 1.05, respectively, which differed from values determined in previous studies. In summary, we were able to identify an inverse isotope effect for the δD values of benzene and toluene

  10. Speciated VOC emission inventory and spatial patterns of ozone formation potential in the Pearl River Delta, China.

    Science.gov (United States)

    Zheng, Junyu; Shao, Min; Che, Wenwei; Zhang, Lijun; Zhong, Liuju; Zhang, Yuanhang; Streets, David

    2009-11-15

    The Pearl River Delta region (PRD) of China has long suffered from severe ground-level ozone pollution. Knowledge of the sources of volatile organic compounds (VOCs) is essential for ozone chemistry. In this work, a speciated VOC emission inventory was established on the basis of updated emissions and local VOC source profiles. The top 10 species, in terms of ozone formation potentials (OFPs), consisted of isoprene, mp-xylene, toluene, ethylene, propene, o-xylene, 1,2,4-trimethylbenzene, 2-methyl-2-butene, 1-butene, and alpha-pinene. These species contributed only 35.9% to VOCs emissions but accounted for 64.1% of the OFP in the region. The spatial patterns of the VOC source inventory agreed well with city-based source apportionment results, especially for vehicle emissions and industry plus VOC product-related emissions. Mapping of the OFPs and measured ozone concentrations indicated that the formation of higher ozone in the south and southeast of the PRD region differed from that in the Conghua area, a remote area in the north of the PRD. We recommend that the priorities for the control of VOC sources include motorcycles, gasoline vehicles, and solvent use because of their larger OFP contributions.

  11. Woodchip bioreactors for N-source reduction in a highly managed agricultural landscape

    Science.gov (United States)

    Kult, K.; Jones, C. S.

    2011-12-01

    Excess nutrification and the resulting hypoxia in the Gulf of Mexico are increasingly understood to originate in managed landscapes of the Upper Mississippi River basin. Nitrogen inputs to cropped fields are high in landscapes with soils containing high organic nitrogen content that, when mineralized, releases nitrogen in the soluble nitrate form. These in situ sources supply extensive subsurface drainage systems that rapidly transport nitrogen to streams and ultimately the Gulf. Aggressive in-field N management can reduce loading to streams, but will not reduce loads to sufficiently impact Gulf hypoxia. Edge of Field (EOF) treatment will be needed to reach water quality objectives. Denitrification bioreactors are one technology being studied for practical and economical EOF nitrate reduction. Bioreactors intercept the high-N tile-drain effluent with woodchip substrates that provide carbon and energy to support denitrification. Iowa Soybean Association (ISA) installed six bioreactors. Design of the ISA bioreactors has focused on the diameter of the field tile and the catchment area. Designs balance discharge with retention times. The bioreactors have been designed to have a 4-hour hydraulic retention time (HRT) capable of treating 20% of peak flow. Denitrification is assumed to follow zero-order kinetics given the high NO3 concentrations in the studied systems. Aerobic organisms must deplete DO sufficiently so anaerobic denitrifying organisms can compete. Insufficient HRT results in unsatisfactory NO3 reductions. Conditions favoring incomplete denitrification can lead to emission of the greenhouse gas N2O. Excessive retention times allow for complete denitrification enabling SO4-reducing bacteria to thrive. This produces undesirable results: conversion of SO4 to H2S, C-source depletion, production of toxic CH3Hg+, and methanogenesis. A flow control structure (FCS) allows for management of HRT by modifying the position of stop logs. Increased HRT reduces the amount

  12. Atmospheric Dispersion Capability for T2VOC

    OpenAIRE

    Oldenburg, Curtis M.

    2005-01-01

    Atmospheric transport by variable-K theory dispersion has been added to T2VOC. The new code, T2VOCA, models flow and transport in the subsurface identically to T2VOC, but includes also the capability for modeling passive multicomponent variable-K theory dispersion in an atmospheric region assumed to be flat, horizontal, and with a logarithmic wind profile. The specification of the logarithmic wind profile in the T2VOC input file is automated through the use of a build code called ATMDISP...

  13. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  14. NO{sub 2} and CO nonattainment areas: a pragmatic approach to source reduction assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, S.; Giugliano, M.; Marzolo, F. [D.I.I.A.R. - Politecnico di Milano, Milan (Italy). Environmental Section

    1995-12-31

    Many Italian large conurbations have CO and NO{sub 2} air quality standards exceeded and, consequently, require control enforcement plans to attain and maintain regulations not respected. In planning the interventions to be undertaken a fundamental issue is represented by the relationships between active emission sources and air quality, commonly described through mathematical models for evaluating the expected effects of the different reduction scenarios. This approach, relatively feasible for slightly or non reactive pollutants like CO, becomes not as easy to be applied for secondary pollutants, like NO{sub 2}, mainly for the complex photo chemical reaction systems involved in their atmospheric presence and the consequent modeling difficulties related either to the description of the system itself than to the detail in input data required. A practicable alternative in this framework relies in the utilization of statistical models for deriving, through the empirical description of the relationships between the parameters of interest, the reduction levels required for complying with the standards. Following an approach already applied with useful results to the same area, present work reports on the development and application to Milan urban area of statistical models for describing the relationships between CO and NO{sub x} annual concentration averages and the corresponding air quality standard parameters (number of standard exceedances for CO and 98th percentile of hourly concentrations for NO{sub 2}). The models are utilised upstream to simple roll-back models for the assessment of the reduction in emissions strength required for attaining air quality standards for the area. (author)

  15. EVALUATION OF LOW-VOC LATEX PAINTS

    Science.gov (United States)

    The paper gives results of an evaluation of four commercially available low-VOC (volatile organic compound) latex paints as substitutes for conventional latex paints by assessing both their emission characteristics and their performance as coatings. Bulk analysis indicated that ...

  16. Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

    Directory of Open Access Journals (Sweden)

    Elizabeth Barksdale Boyle

    2016-03-01

    Full Text Available Epidemiologic studies can measure exposure to volatile organic compounds (VOCs using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS. We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking and by observations by a trained data collector (presence of scented products in homes. We found several significant (p < 0.01 relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite

  17. Assessment of Exposure to VOCs among Pregnant Women in the National Children’s Study

    Science.gov (United States)

    Boyle, Elizabeth Barksdale; Viet, Susan M.; Wright, David J.; Merrill, Lori S.; Alwis, K. Udeni; Blount, Benjamin C.; Mortensen, Mary E.; Moye, John; Dellarco, Michael

    2016-01-01

    Epidemiologic studies can measure exposure to volatile organic compounds (VOCs) using environmental samples, biomarkers, questionnaires, or observations. These different exposure assessment approaches each have advantages and disadvantages; thus, evaluating relationships is an important consideration. In the National Children’s Vanguard Study from 2009 to 2010, participants completed questionnaires and data collectors observed VOC exposure sources and collected urine samples from 488 third trimester pregnant women at in-person study visits. From urine, we simultaneously quantified 28 VOC metabolites of exposure to acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride, and xylene exposures using ultra high performance liquid chromatography coupled with an electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS) method. Urinary thiocyanate was measured using an ion chromatography coupled with an electrospray ionization tandem mass spectrometry method (IC-ESI/MSMS). We modeled the relationship between urinary VOC metabolite concentrations and sources of VOC exposure. Sources of exposure were assessed by participant report via questionnaire (use of air fresheners, aerosols, paint or varnish, organic solvents, and passive/active smoking) and by observations by a trained data collector (presence of scented products in homes). We found several significant (p < 0.01) relationships between the urinary metabolites of VOCs and sources of VOC exposure. Smoking was positively associated with metabolites of the tobacco constituents acrolein, acrylamide, acrylonitrile, 1,3-butadiene, crotonaldehyde, cyanide, ethylene oxide, N,N-dimethylformamide, propylene oxide, styrene, and xylene. Study location was negatively associated with the toluene metabolite N

  18. Detection and quantification of methane and VOC emissions from oil and gas production operations using remote measurements, Interim report

    Science.gov (United States)

    Improved understanding of air pollutant emissions from oil and gas production operations is needed. With a steadily increasing number of production sources, the impact of emitted volatile organic compounds (VOCs) on regional ozone is potentially significant. As the separation dis...

  19. A refined 2010-based VOC emission inventory and its improvement on modeling regional ozone in the Pearl River Delta Region, China.

    Science.gov (United States)

    Yin, Shasha; Zheng, Junyu; Lu, Qing; Yuan, Zibing; Huang, Zhijiong; Zhong, Liuju; Lin, Hui

    2015-05-01

    Accurate and gridded VOC emission inventories are important for improving regional air quality model performance. In this study, a four-level VOC emission source categorization system was proposed. A 2010-based gridded Pearl River Delta (PRD) regional VOC emission inventory was developed with more comprehensive source coverage, latest emission factors, and updated activity data. The total anthropogenic VOC emission was estimated to be about 117.4 × 10(4)t, in which on-road mobile source shared the largest contribution, followed by industrial solvent use and industrial processes sources. Among the industrial solvent use source, furniture manufacturing and shoemaking were major VOC emission contributors. The spatial surrogates of VOC emission were updated for major VOC sources such as industrial sectors and gas stations. Subsector-based temporal characteristics were investigated and their temporal variations were characterized. The impacts of updated VOC emission estimates and spatial surrogates were evaluated by modeling O₃ concentration in the PRD region in the July and October of 2010, respectively. The results indicated that both updated emission estimates and spatial allocations can effectively reduce model bias on O₃ simulation. Further efforts should be made on the refinement of source classification, comprehensive collection of activity data, and spatial-temporal surrogates in order to reduce uncertainty in emission inventory and improve model performance. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Investigation and Measurement of Volatile Organic Compounds (VOC) at indoor Quality of Working Places which contain Paint-based Biocidal Products

    OpenAIRE

    Koçak, Talha Kemal; Karasu Benli, Aysel Çağlan

    2017-01-01

    Purpose:The quality of air inside enclosed spaces, especially in industrial workplaces,has become a matter of growing concern over the last two decades. Volatileorganic compounds (VOCs) in confined spaces are the most threatening pollutersfor both the environment and human health, and paint-based biocidal productsare significant VOC sources. Our main purpose of study is to measure andanalyze indoor VOC in dyeing sector and evaluate the findings according to theoccupational health and safety r...

  1. Monitoring by Control Technique - Compliant (Low/No VOC/HAP) Inks and Coatings

    Science.gov (United States)

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about Compliant (Low/No VOC/HAP) Inks and Coatings control techniques used to reduce pollutant emissions.

  2. Volatile organic compounds (VOCs) removal in non-thermal plasma double dielectric barrier discharge reactor.

    Science.gov (United States)

    Mustafa, Muhammad Farooq; Fu, Xindi; Liu, Yanjun; Abbas, Yawar; Wang, Hongtao; Lu, Wenjing

    2018-04-05

    Non-thermal plasma (NTP) an emerging technology to treat volatile organic compounds (VOCs) present in unhygienic point source air streams. In present study, double dielectric barrier discharge (DDBD) reactors were used for the first time to evaluate the removal efficiency of VOCs mixture of different nature at constant experimental conditions (input power 16-65.8 W, VOCs mixture feeding rate 1-6 L/min, 100-101 ppm inlet concentration of individual VOC). Reactor A and B with discharge gap at 6 mm and 3 mm respectively, were used in current study. When treated at an input power of 53.7 W with gas feeding rate of 1 L/min in DDBD reactor A, removal efficiency of the VOCs were: tetrachloroethylene (100%), toluene (100%), trichloroethylene (100%), benzene (100%), ethyl acetate (100%) and carbon disulfide (88.30%); whereas in reactor B, the removal efficiency of all VOCs were 100%. Plasma-catalyst (Pt-Sn/Al 2 O 3 , BaTiO 3 and HZSM-5) synergistic effect on VOCs removal efficiency was also investigated. Highest removal efficiency i.e 100% was observed for each compound with BaTiO 3 and HZSM-5 at an input power 65.8 W. However, integrating NTP with BaTiO 3 and HZSM-5 leads to enhanced removal performance of VOCs mixture with high activity, increase in energy efficiency and suppression of unwanted byproducts. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Underestimated public health risks caused by overestimated VOC removal in wastewater treatment processes.

    Science.gov (United States)

    Yang, Junchen; Wang, Kun; Zhao, Qingliang; Huang, Likun; Yuan, Chung-Shin; Chen, Wei-Hsiang; Yang, Wen-Bin

    2014-02-01

    The uncontrolled release of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) and the adverse health effects on the public have been of increasing concern. In this study, a lab-scale bioreactor was prepared to analyze the mass distribution of three aromatic (benzene, toluene, and xylenes) and four chlorinated VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) among the air, water and sludge phases in wastewater treatment processes. The VOC distribution through a full-scale WWTP in northern China was further investigated with respect to the effects of seasonal temperature variations and treatment technologies, followed by the cancer risk assessment using a steady-state Gaussian plume model (Industrial Source Complex) to simulate the atmospheric behaviors of the VOCs emitted from the WWTP. It was found that three aromatic hydrocarbons, notably benzene, were more readily released from the wastewater into the atmosphere, whereas the chlorinated compounds except chloroform were mainly present in the water phase through the treatment processes. The primary clarifier was the technology releasing high levels of VOCs into the atmosphere from the wastewater. The extents of volatilization or biodegradation, two important mechanisms to remove VOCs from wastewater, appeared to be determined by the physicochemical characteristics of the compounds, as the influence of treatment technologies (e.g., aeration) and seasonal temperature variations was rather limited. More importantly, the people living in the areas even more than 4 km away from the WWTP were still potentially exposed to cancer risks exceeding the regulatory threshold limit. The findings described the complex nature of VOC emissions from WWTPs and quantitatively indicated that the associated health impacts on the public near the WWTPs could be severely underestimated, whereas their treatment efficiencies by wastewater treatment technologies were overestimated

  4. VOC emission into the atmosphere by trees and leaf litter in Polish forests

    Science.gov (United States)

    Isidorov, V.; Smolewska, M.; Tyszkiewicz, Z.

    2009-04-01

    It is generally recognized at present that the vegetation of continents is the principal source of reactive volatile organic compounds (VOC) of the atmosphere. The upper limit of the evaluation of global phytogenic VOC is 1100-1500 Tg/yr (Isidorov, 1990; Guenther et al., 1995). Although these global evaluations showing the place of phytogenic emission among of other VOC sources are important, evaluations for individual countries are also very important. This poster represents the results of the estimation of VOC emission from Polish forests. Calculations took into account the composition and age of forests. According to our estimation, the total VOC emission by the arboreal vegetation differs from 190 to 750 kt/yr, depending of weather conditions in different years. There are only few studies conducted on decaying plant material as a source of atmospheric VOCs, but still they are able to give evidence of the importance of this source. For Polish forests, the litter mass is estimated to be (16-19)106 t/yr. These organic materials undergo decomposition by mesofauna and microorganisms. In these processes volatile organic compounds (VOC) stored in the litter and secondary metabolites of litter-destroying fungi are emitted into the atmosphere. The scale of the phenomenon makes leaf litter an important VOC source in the atmosphere. The filling of numerous gaps in researches of VOC emissions from decomposing leaf litter demands carrying out of long term field experiments in various climatic conditions. In this communication we report also the results of 3.5-year experiment on qualitative and quantitative GC-MS investigations of VOC emitted into the gas phase from leaves litter of some species of deciduous and coniferous trees of Polish forests. Apart from terpenes and their oxygenated derivatives, which are usual in plant tissues, leaf litter intensively emits vast amounts of lower alcohols and carbonyl compounds. We suppose that these volatile substances are products

  5. Reducing VOC Press Emission from OSB Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Gary D. McGinnis; Laura S. WIlliams; Amy E. Monte; Jagdish Rughani: Brett A. Niemi; Thomas M. Flicker

    2001-12-31

    Current regulations require industry to meet air emission standards with regard to particulates, volatile organic compounds (VOCs), hazardous air pollutants (HAPs) and other gases. One of many industries that will be affected by the new regulations is the wood composites industry. This industry generates VOCs, HAPs, and particulates mainly during the drying and pressing of wood. Current air treatment technologies for the industry are expensive to install and operate. As regulations become more stringent, treatment technologies will need to become more efficient and cost effective. The overall objective of this study is to evaluate the use of process conditions and chemical additives to reduce VOC/HAPs in air emitted from presses and dryers during the production of oriented strand board.

  6. VOC emission rates over London and South East England obtained by airborne eddy covariance.

    Science.gov (United States)

    Vaughan, Adam R; Lee, James D; Shaw, Marvin D; Misztal, Pawel K; Metzger, Stefan; Vieno, Massimo; Davison, Brian; Karl, Thomas G; Carpenter, Lucy J; Lewis, Alastair C; Purvis, Ruth M; Goldstein, Allen H; Hewitt, C Nicholas

    2017-08-24

    Volatile organic compounds (VOCs) originate from a variety of sources, and play an intrinsic role in influencing air quality. Some VOCs, including benzene, are carcinogens and so directly affect human health, while others, such as isoprene, are very reactive in the atmosphere and play an important role in the formation of secondary pollutants such as ozone and particles. Here we report spatially-resolved measurements of the surface-to-atmosphere fluxes of VOCs across London and SE England made in 2013 and 2014. High-frequency 3-D wind velocities and VOC volume mixing ratios (made by proton transfer reaction - mass spectrometry) were obtained from a low-flying aircraft and used to calculate fluxes using the technique of eddy covariance. A footprint model was then used to quantify the flux contribution from the ground surface at spatial resolution of 100 m, averaged to 1 km. Measured fluxes of benzene over Greater London showed positive agreement with the UK's National Atmospheric Emissions Inventory, with the highest fluxes originating from central London. Comparison of MTBE and toluene fluxes suggest that petroleum evaporation is an important emission source of toluene in central London. Outside London, increased isoprene emissions were observed over wooded areas, at rates greater than those predicted by a UK regional application of the European Monitoring and Evaluation Programme model (EMEP4UK). This work demonstrates the applicability of the airborne eddy covariance method to the determination of anthropogenic and biogenic VOC fluxes and the possibility of validating emission inventories through measurements.

  7. VOC methods and levels in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Bomboi, M.T. [Area de Contaminacion Atmosferica, Instituto de Salud Carlos III, Majadahonda (Spain)

    2004-07-01

    Ozone precursors began to be studied in the eighties in Spain, in order to know their levels and composition in areas, which had high concentrations of other atmospheric polluting agents. At the end of the eighties, VOC were incorporated into the air quality networks in urban areas in order to anticipate at the derived amendments of the entrance into force on the Directive 92/72/CEE of 1992 on air pollution by ozone. At the same time, field campaigns for VOC toxics were started in specific industrial areas and the zones with high traffic. More recently, the air quality networks have been orientated to non-urban areas, to cover the knowledge of VOC in semi-urban and rural areas. On the other hand, the role of the biogenic emissions and the role that their chemical and photochemical products play in atmospheric chemistry was becoming important in the nineties. Therefore some research projects, e.g. 'Biogenic Emissions in the Mediterranean Area (BEMA)', were developed in order to understand the vegetation emissions in the Mediterranean area in relation to anthropogenic compounds and to get information on their participation in tropospheric ozone formation. VOC have been sampled at European Monitoring and Evaluation Programme (EMEP) sites since 1999, based on recommendations from the EMEP Workshop on Measurements of Hydrocarbons/VOC in Lindau 1989. Collection of light hydrocarbons started in 1999, whereas measurements of carbonyls have just started in 2003. In this work, the most important sampling and analysis techniques to determine ozone precursors and to control VOC are shown, as well as the main results obtained in projects, networks and measurement campaigns performed with these methods.

  8. Time-activity relationships to VOC personal exposure factors

    Science.gov (United States)

    Edwards, Rufus D.; Schweizer, Christian; Llacqua, Vito; Lai, Hak Kan; Jantunen, Matti; Bayer-Oglesby, Lucy; Künzli, Nino

    Social and demographic factors have been found to play a significant role in differences between time-activity patterns of population subgroups. Since time-activity patterns largely influence personal exposure to compounds as individuals move across microenvironments, exposure subgroups within the population may be defined by factors that influence daily activity patterns. Socio-demographic and environmental factors that define time-activity subgroups also define quantifiable differences in VOC personal exposures to different sources and individual compounds in the Expolis study. Significant differences in exposures to traffic-related compounds ethylbenzene, m- and p-xylene and o-xylene were observed in relation to gender, number of children and living alone. Categorization of exposures further indicated time exposed to traffic at work and time in a car as important determinants. Increased exposures to decane, nonane and undecane were observed for males, housewives and self-employed. Categorization of exposures indicated exposure subgroups related to workshop use and living downtown. Higher exposures to 3-carene and α-pinene commonly found in household cleaning products and fragrances were associated with more children, while exposures to traffic compounds ethylbenzene, m- and p-xylene and o-xylene were reduced with more children. Considerable unexplained variation remained in categorization of exposures associated with home product use and fragrances, due to individual behavior and product choice. More targeted data collection methods in VOC exposure studies for these sources should be used. Living alone was associated with decreased exposures to 2-methyl-1-propanol and 1-butanol, and traffic-related compounds. Identification of these subgroups may help to reduce the large amount of unexplained variation in VOC exposure studies. Further they may help in assessing impacts of urban planning that result in changes in behavior of individuals, resulting in shifts in

  9. VOC breath biomarkers in lung cancer.

    Science.gov (United States)

    Saalberg, Yannick; Wolff, Marcus

    2016-08-01

    This review provides an overview of volatile organic compounds (VOCs) which are considered lung cancer biomarkers for diagnostic breath analysis. It includes results of scientific publications from 1985 to 2015. The identified VOCs are listed and ranked according to their occurrence of nomination. The applied detection and sampling methods are specified but not evaluated. Possible reasons for the different results of the studies are stated. Among the most frequently emerging biomarkers are 2-butanone and 1-propanol as well as isoprene, ethylbenzene, styrene and hexanal. The outcome of this review may be helpful for the development of a lung cancer screening device. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Evaluation of volatile organic compound (VOC) blank data and application of study reporting levels to groundwater data collected for the California GAMA Priority Basin Project, May 2004 through September 2010

    Science.gov (United States)

    Fram, Miranda S.; Olsen, Lisa D.; Belitz, Kenneth

    2012-01-01

    quality of the data from groundwater samples, it was necessary to apply different methods of determining SRLs from field blank data to different VOCs, rather than use the same method for all VOCs. Four potential SRL values were defined by using three approaches: two values were defined by using a binomial probability method based on one-sided, nonparametric upper confidence limits, one was defined as equal to the maximum concentration detected in the field blanks, and one was defined as equal to the maximum laboratory method detection level used during the period when samples were collected for the project. The differences in detection frequencies and concentrations among different types of blanks (laboratory instrument blanks, source-solution blanks, and field blanks collected with three different sampling equipment configurations) and groundwater samples were used to infer the sources and mechanisms of contamination for each VOC detection in field blanks. Other chemical data for the groundwater samples (oxidation-reduction state, co-occurrence of VOCs, groundwater age) and ancillary information about the well sites (land use, presence of known sources of contamination) were used to evaluate whether the patterns of detections of VOCs in groundwater samples before and after application of potential SRLs were plausible. On this basis, the appropriate SRL was selected for each VOC that was determined to require an SRL. The SRLs for ethylbenzene [0.06 microgram per liter (μg/L)], m- and p-xylenes (0.33 μg/L), o-xylene (0.12 μg/L), toluene (0.69 μg/L), and 1,2,4-trimethylbenzene (0.56 μg/L) corresponded to the highest concentrations detected in the QCFBs and were selected because they resulted in the most censoring of groundwater data. Comparisons of hydrocarbon ratios in groundwater samples and blanks and comparisons between detection frequencies of the five hydrocarbons in groundwater samples and different types of blanks suggested three dominant sources of

  11. [Comparison Analysis of Economic and Engineering Control of Industrial VOCs].

    Science.gov (United States)

    Wang, Yu-fei; Liu, Chang-xin; Cheng, Jie; Hao, Zheng-ping; Wang, Zheng

    2015-04-01

    Volatile organic compounds (VOCs) pollutant has become China's major air pollutant in key urban areas like sulfur dioxide, nitrogen oxides and particulate matter. It is mainly produced from industry sectors, and engineering control is one of the most important reduction measures. During the 12th Five-Year Plan, China decides to invest 40 billion RMB to build pollution control projects in key industry sectors with annual emission reduction of 605 000 t x a(-1). It shows that China attaches a great importance to emission reduction by engineering projects and highlights the awareness of engineering reduction technologies. In this paper, a macroeconomic model, namely computable general equilibrium model, (CGE model) was employed to simulate engineering control and economic control (imposing environmental tax). We aim to compare the pros and cons of the two reduction policies. Considering the economic loss of the whole country, the environmental tax has more impacts on the economy system than engineering reduction measures. We suggest that the central government provides 7 500 RMB x t(-1) as subsidy for enterprises in industry sectors to encourage engineering reduction.

  12. An open-source Matlab code package for improved rank-reduction 3D seismic data denoising and reconstruction

    Science.gov (United States)

    Chen, Yangkang; Huang, Weilin; Zhang, Dong; Chen, Wei

    2016-10-01

    Simultaneous seismic data denoising and reconstruction is a currently popular research subject in modern reflection seismology. Traditional rank-reduction based 3D seismic data denoising and reconstruction algorithm will cause strong residual noise in the reconstructed data and thus affect the following processing and interpretation tasks. In this paper, we propose an improved rank-reduction method by modifying the truncated singular value decomposition (TSVD) formula used in the traditional method. The proposed approach can help us obtain nearly perfect reconstruction performance even in the case of low signal-to-noise ratio (SNR). The proposed algorithm is tested via one synthetic and field data examples. Considering that seismic data interpolation and denoising source packages are seldom in the public domain, we also provide a program template for the rank-reduction based simultaneous denoising and reconstruction algorithm by providing an open-source Matlab package.

  13. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Riis, Charlotte; Christensen, Anders G.

    2012-01-01

    Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first...

  14. Hexavalent chromium reduction by Cellulomonas sp. strain ES6: the influence of carbon source, iron minerals, and electron shuttling compounds.

    Science.gov (United States)

    Field, Erin K; Gerlach, Robin; Viamajala, Sridhar; Jennings, Laura K; Peyton, Brent M; Apel, William A

    2013-06-01

    The reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III), can be an important aspect of remediation processes at contaminated sites. Cellulomonas species are found at several Cr(VI) contaminated and uncontaminated locations at the Department of Energy site in Hanford, Washington. Members of this genus have demonstrated the ability to effectively reduce Cr(VI) to Cr(III) fermentatively and therefore play a potential role in Cr(VI) remediation at this site. Batch studies were conducted with Cellulomonas sp. strain ES6 to assess the influence of various carbon sources, iron minerals, and electron shuttling compounds on Cr(VI) reduction rates as these chemical species are likely to be present in, or added to, the environment during in situ bioremediation. Results indicated that the type of carbon source as well as the type of electron shuttle present influenced Cr(VI) reduction rates. Molasses stimulated Cr(VI) reduction more effectively than pure sucrose, presumably due to presence of more easily utilizable sugars, electron shuttling compounds or compounds with direct Cr(VI) reduction capabilities. Cr(VI) reduction rates increased with increasing concentration of anthraquinone-2,6-disulfonate (AQDS) regardless of the carbon source. The presence of iron minerals and their concentrations did not significantly influence Cr(VI) reduction rates. However, strain ES6 or AQDS could directly reduce surface-associated Fe(III) to Fe(II), which was capable of reducing Cr(VI) at a near instantaneous rate. These results suggest the rate limiting step in these systems was the transfer of electrons from strain ES6 to the intermediate or terminal electron acceptor whether that was Cr(VI), Fe(III), or AQDS.

  15. The Crowding-Out Effects of Garbage Fees and Voluntary Source Separation Programs on Waste Reduction: Evidence from China

    Directory of Open Access Journals (Sweden)

    Hongyun Han

    2016-07-01

    Full Text Available This paper examines how and to what degree government policies of garbage fees and voluntary source separation programs, with free indoor containers and garbage bags, can affect the effectiveness of municipal solid waste (MSW management, in the sense of achieving a desirable reduction of per capita MSW generation. Based on city-level panel data for years 1998–2012 in China, our empirical analysis indicates that per capita MSW generated is increasing with per capita disposable income, average household size, education levels of households, and the lagged per capita MSW. While both garbage fees and source separation programs have separately led to reductions in per capita waste generation, the interaction of the two policies has resulted in an increase in per capita waste generation due to the following crowding-out effects: Firstly, the positive effect of income dominates the negative effect of the garbage fee. Secondly, there are crowding-out effects of mandatory charging system and the subsidized voluntary source separation on per capita MSW generation. Thirdly, small subsidies and tax punishments have reduced the intrinsic motivation for voluntary source separation of MSW. Thus, compatible fee charging system, higher levels of subsidies, and well-designed public information and education campaigns are required to promote household waste source separation and reduction.

  16. Airborne VOC measurements on board the Zeppelin NT during the PEGASOS campaigns in 2012 deploying the improvement Fast-GC-MSD system

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Julia Elisabeth

    2014-04-01

    Volatile organic compounds (VOCs) comprise a large number of different species, estimated to 10{sup 4}-10{sup 6}. They are emitted on the Earth's surface from a variety of biogenic and anthropogenic sources. VOCs are removed by multiple pathways from the atmosphere, by oxidation and finally by dry or wet deposition. Most primary emitted VOCs are non-polar and therefore have a low solubility in water. Oxidation facilitates efficient VOC removal by wet deposition. In the atmosphere the main photochemical VOC oxidation agent is the OH radical. As a consequence the polarity of the VOCs is increased and they can be removed faster. The oxidation of VOCs proceeds in several steps until the VOCs are deposited or are eventually oxidized to carbon dioxide. A downside of the VOCs oxidation process lies in the production of significant amounts ozone if nitrogen oxide is present which is a serious health hazard. Most of the VOC oxidation takes place in lower part of the atmosphere between the altitudes of 100 to 1000 m, which is only sparsely analyzed. Therefore, fast VOCs measurements by GC-MSD on board the Zeppelin NT offered new important insights in the distribution of VOCs. The measurements were performed within the PEAGSOS campaigns in the Netherlands and in Italy in 2012. For the implementation of the GC-MSD system (HCG) on board the Zeppelin it was reconstructed to enhance its performance and to meet aviation requirements. The system was optimized to measure VOCs ranging from C4 to C10 as well as oxygenated VOCs (OVOCs) with a detection limit below 10 ppt. The analyzed VOCs for both parts of the campaigns showed low mean concentration below 5 ppb for all VOCs. Especially, the mixing ratios of the primary emitted VOCs were very low with mean values lower than 200 ppt. Higher concentrations could be observed for the OVOCs with mean concentrations up to 5 ppb. The most abundant OVOCs apart from formaldehyde were methanol, ethanol, acetone and acetaldehyde.

  17. VOC transport in vented drums containing simulated waste sludge

    Energy Technology Data Exchange (ETDEWEB)

    Liekhus, K.J.; Gresham, G.L.; Rae, C.; Connolly, M.J.

    1994-02-01

    A model is developed to estimate the volatile organic compound (VOC) concentration in the headspace of the innermost layer of confinement in a lab-scale vented waste drum containing simulated waste sludge. The VOC transport model estimates the concentration using the measured VOC concentration beneath the drum lid and model parameters defined or estimated from process knowledge of drum contents and waste drum configuration. Model parameters include the VOC diffusion characteristic across the filter vent, VOC diffusivity in air, size of opening in the drum liner lid, the type and number of layers of polymer bags surrounding the waste, VOC permeability across the polymer, and the permeable surface area of the polymer bags. Comparison of model and experimental results indicates that the model can accurately estimate VOC concentration in the headspace of the innermost layer of confinement. The model may be useful in estimating the VOC concentration in actual waste drums.

  18. Noise of combat aircraft in proximity to air bases: Review of the possibilities of noise reduction at the source

    Science.gov (United States)

    Collin, D.; Julliard, J.; Riou, G.

    1992-04-01

    The operations carried out by combat aircraft are a source of nuisance for the populations situated in proximity to air bases. The noise of jet aircraft constitutes the dominant source of noise in the operations in question. The authors propose to approach the question of the reduction of the corresponding sonic nuisances by utilizing experience acquired by SNECMA over the course of more than twenty years of research on the noise of civil jet turbine engines, and especially of the Concorde supersonic transport program. The important experimental database resulting from these studies has permitted the development and evaluation of preview methods and solutions in noise reduction. The different mechanisms and significant sources of noise will therefore be reviewed at the same time as the possibilities for current or future improvement.

  19. Noise reduction of high-power supercontinuum sources by back seeding

    DEFF Research Database (Denmark)

    Moselund, Peter Morten; Frosz, Michael Henoch; Thomsen, Carsten L.

    2009-01-01

    We investigate noise reduction in seeded supercontinuum generation at powers above the supercontinuum generation threshold and show that seeding of supercontinuum is also beneficial at high pump powers.......We investigate noise reduction in seeded supercontinuum generation at powers above the supercontinuum generation threshold and show that seeding of supercontinuum is also beneficial at high pump powers....

  20. Low VOC Barrier Coating for Industrial Maintenance

    Science.gov (United States)

    2012-09-01

    a millable gum polysulfide known as the first synthetic rubber commercially made in the United States. Today, there are several liquid polysulfide...polymers have the same excellent overall solvent resistance properties as the millable gum polysulfides. However, the liquid polysulfides have the...VOC Total Solids (wt) Total Solids (volume) Percent Pigment Stormer Viscosity Brookfield Viscosity Pot Life Sag Resistance Theoretical

  1. Effects of cold temperature and ethanol content on VOC emissions from light-duty gasoline vehicles

    Science.gov (United States)

    Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle...

  2. [Pollution characteristics and health risk assessment of atmospheric VOCs in the downtown area of Guangzhou, China].

    Science.gov (United States)

    Li, Lei; Li, Hong; Wang, Xue-Zhong; Zhang, Xin-Min; Wen, Chong

    2013-12-01

    The measurements of 31 kinds of VOCs in the ambient air of a site were carried out in the downtown of Guangzhou by online method from November 5, 2009 to November 9, 2009. The ambient level and composition characteristics, temporal variation characteristics, sources identification, and chemical reactivity of VOCs were studied, and the health risk of VOCs in the ambient air in the study area was assessed by using the international recognized health risk assessment method. Results showed that the mean and the range of the mass concentrations of 31 VOCs were 114.51 microg x m(-3) and 29.42-546.06 microg x m(-3), respectively. The mass concentrations of 31 VOCs, and those of alkanes, alkenes, and aromatics all showed a changing trend of higher in the morning and in the evening, and lower at noontime. Vehicular exhaust, gasoline and liquefied petroleum gas evaporates were the main sources of VOCs with the volatilization of paints and solvents being important emission sources. Toluene, trans-2-butene, m/p-xylene, i-butane, and 1,3,5-trimethylbenzene were the key reactive species among the 31 VOCs. Vehicular exhaust and gasoline evaporation were the main sources of VOCs leading to the formation of ozone. Health risk assessment showed that n-hexane, 1,3-butadiene, benzene, toluene, ethylbenzene, m/p-xylene and o-xylene had no appreciable risk of adverse non-cancer health effect on the exposed population, but 1, 3-butadiene and benzene had potential cancer risk. By comparing the corresponding data about health risk assessment of benzene compounds in some cities in China, it is concluded that benzene can impose relatively high cancer risk to the exposed populations in the ambient air of some cities in China. Therefore, strict countermeasures should be taken to further control the pollution of benzene in the ambient air of cities, and it is imperative to start the related studies and develop the atmospheric environmental health criteria and national ambient air quality

  3. Variability of indoor and outdoor VOC measurements: An analysis using variance components

    Science.gov (United States)

    Jia, Chunrong; Batterman, Stuart A.; Relyea, George E.

    2014-01-01

    This study examines concentrations of volatile organic compounds (VOCs) measured inside and outside of 162 residences in southeast Michigan, U.S.A. Nested analyses apportioned four sources of variation: city, residence, season, and measurement uncertainty. Indoor measurements were dominated by seasonal and residence effects, accounting for 50 and 31%, respectively, of the total variance. Contributions from measurement uncertainty (VOC concentrations can use multi-seasonal measurements at centralized locations. Error models showed that uncertainties at low concentrations might obscure effects of other factors. Variance component analyses can be used to interpret existing measurements, design effective exposure studies, and determine whether the instrumentation and protocols are satisfactory. PMID:21995872

  4. Ambient Volatile Organic Compounds (VOCs) pollution in Isolo ...

    African Journals Online (AJOL)

    The results from analysis of the air samples collected showed that twenty-six (26) VOCs were captured in Isolo Industrial area. The VOCs were classified thus: aromatics 41%, halogenated 42%, esters 3%, ketones 8%, alcohols 4%, and ethers 2%. There is a significant difference (P < 0.05) between the levels of VOCs in ...

  5. 40 CFR 52.2225 - VOC rule deficiency correction.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false VOC rule deficiency correction. 52.2225... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Tennessee § 52.2225 VOC rule... be added to the term “VOC/gallon solids” as a clarification. (3) The term “vapor-tight” should be...

  6. 40 CFR 52.2126 - VOC rule deficiency correction.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false VOC rule deficiency correction. 52.2126... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) South Carolina § 52.2126 VOC rule... Health and Environmental Control: (a) South Carolina's VOC regulations contain no method for determining...

  7. Release of VOCs and particles during use of nanofilm spray products.

    Science.gov (United States)

    Nørgaard, Asger W; Jensen, Keld A; Janfelt, Christian; Lauritsen, Frants R; Clausen, Per A; Wolkoff, Peder

    2009-10-15

    Here, we present emission data on VOCs and particles emitted during simulated use of four commercial nanofilm spray products (NFPs) used for making easy-to-clean or self-cleaning surfaces on floors, ceramic tiles, and windows. The aim was to characterize the emitted VOCs and to provide specific source strength data for VOCs and particles released to the airduring use of the products. Containers with NFP were mounted on a spray-stand inside a closed stainless steel chamber with no air exchange. NFPs were sprayed in amounts corresponding to 1 m2 surface toward a target plate at a distance of 35 cm. Released VOCs were measured by a combination of air sampling on Tenax TA adsorbent followed by thermal desorption GC/MS and GC/FID analysis and real time measurements using a miniature membrane inlet mass spectrometer. Particles were measured using a fast mobility particle sizer and an aerosol particle sizer. A number of VOCs were identified, including small alcohols, ketones and ethers, chlorinated acetones, a perfluorinated silane, limonene, and cyclic siloxanes. The number of generated particles was on the order of 3 x 10(8) to 2 x 10(10) particles/m3 per g sprayed NFP and were dominated by nanosize particles.

  8. Bubble-Facilitated VOC Transport from LNAPL Smear Zones and Its Potential Effect on Vapor Intrusion.

    Science.gov (United States)

    Soucy, Nicole C; Mumford, Kevin G

    2017-03-07

    Most conceptual and mathematical models of soil vapor intrusion assume that the transport of volatile organic compounds (VOCs) from a source toward a building is limited by diffusion through the soil gas. Under conditions where advection occurs, transport rates are higher and can lead to higher indoor air concentrations. Advection-dominated conditions can be created by gas bubble flow in the saturated zone. A series of laboratory column experiments were conducted to measure mass flux due to bubble-facilitated VOC transport from light nonaqueous phase liquid (LNAPL) smear zones. Smear zones that contained both LNAPL residual and trapped gas, as well as those that contained only LNAPL residual, were investigated. Results showed that the VOC mass flux due to bubble-facilitated transport was orders-of-magnitude higher than under diffusion-limited conditions. Results also showed that the mass flux due to bubble-facilitated transport was intermittent, and increased with an increased supply of dissolved gases.

  9. Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

    Science.gov (United States)

    2017-06-20

    with Other Remedial Options ........ 56  v ACRONYMS AND ABBREVIATIONS bgs Below ground surface CaCl2 Calcium chloride cis-1,2-DCE cis-1,2...for a one acre site). Project Tasks  Task 1: Research Flux Reduction Materials: Several novel silica gel/vegetable oil- formulations were...enhanced reductive dechlorination zone when the competing electron acceptors are diverted. One research paper (Newell and Aziz, 2004) estimate a

  10. Tracking the sources of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.; Churkina, G.; Coates, J.; Grote, R.; Mar, K.; von Schneidemesser, E.; Zhu, S.

    2013-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this set of studies we examine the attribution of tropospheric ozone to emissions of VOC using a tagging approach, whereby each VOC oxidation intermediate in model chemical mechanisms is tagged with the identity of its primary emitted compound, allowing modelled ozone production to be directly attributed to all emitted VOCs in the model. Using a global model we

  11. CHARACTERIZATION OF LOW-VOC LATEX PAINTS: VOLATILE ORGANIC COMPOUND CONTENT, VOC AND ALDEHYDE EMISSIONS, AND PAINT PERFORMANCE

    Science.gov (United States)

    The report gives results of laboratory tests to evaluate commercially available latex paints advertised as "low-odor," "low-VOC (volatile organic compound)," or "no-VOC." Measurements were performed to quantify the total content of VOCs in the paints...

  12. An extended dual input dual output three level Z source inverter with improved switch loss reduction technique

    Directory of Open Access Journals (Sweden)

    N.B. Deshmukh

    2016-12-01

    Full Text Available Multilevel inverter (MLI is a proven technology used for industrial applications due to low output total harmonic distortion (THD, high power handling capability and low active device rating. Dual output inverter is a recent trend associated with inverter topologies for specialized applications. This paper deals with three phase three level dual input dual output inverter topology with minimum active device count. Reduction in switch count leads to reduction in losses and improves reliability. Both the input sources share power equally as neutral point current ripple is maintained low. For further reduction in switching losses at higher switching frequencies, the concept of “no switching zone” or discontinuous pulse width modulation (DPWM has been put forth recently. This paper proposes modification in the placement of “no switching zone” in order to optimize switching losses and output THD (output filtering requirements for low power factor load. This study also proposes novel graphical approach to analyze the loss reduction along with its effect on output THD. The sinusoidal PWM (SPWM is used which gives satisfactory switching loss reduction without complex calculations. Moreover, the proposed topology is generalized to provide dual output at higher voltage levels. It is seen that the components reduction phenomenon becomes more pronounced as number of levels goes on increasing. The proposed converter is simulated in MATLAB software environment and results are obtained.

  13. Trends of VOC exposures among a nationally representative sample: Analysis of the NHANES 1988 through 2004 data sets.

    Science.gov (United States)

    Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

    2011-09-01

    Exposures to volatile organic compounds (VOCs) are ubiquitous due to emissions from personal, commercial and industrial products, but quantitative and representative information regarding long term exposure trends is lacking. This study characterizes trends from1988 to 2004 for the 15 VOCs measured in blood in five cohorts of the National Health and Nutrition Examination Survey (NHANES), a large and representative sample of U.S. adults. Trends were evaluated at various percentiles using linear quantile regression (QR) models, which were adjusted for solvent-related occupations and cotinine levels. Most VOCs showed decreasing trends at all quantiles, e.g., median exposures declined by 2.5 (m, p-xylene) to 6.4 (tetrachloroethene) percent per year over the 15 year period. Trends varied by VOC and quantile, and were grouped into three patterns: similar decreases at all quantiles (including benzene, toluene); most rapid decreases at upper quantiles (ethylbenzene, m, p-xylene, o-xylene, styrene, chloroform, tetrachloroethene); and fastest declines at central quantiles (1,4-dichlorobenzene). These patterns reflect changes in exposure sources, e.g., upper-percentile exposures may result mostly from occupational exposure, while lower percentile exposures arise from general environmental sources. Both VOC emissions aggregated at the national level and VOC concentrations measured in ambient air also have declined substantially over the study period and are supportive of the exposure trends, although the NHANES data suggest the importance of indoor sources and personal activities on VOC exposures. While piecewise QR models suggest that exposures of several VOCs decreased little or any during the 1990's, followed by more rapid decreases from 1999 to 2004, questions are raised concerning the reliability of VOC data in several of the NHANES cohorts and its applicability as an exposure indicator, as demonstrated by the modest correlation between VOC levels in blood and personal

  14. Feasibility Analysis of Sustainability-Based Measures to Reduce VOC Emissions in Office Partition Manufacturing

    Directory of Open Access Journals (Sweden)

    Marc A. Rosen

    2010-02-01

    Full Text Available A feasibility analysis is reported of reduction opportunities for volatile organic compound (VOC emissions in manufacturing office furniture partitions, aimed at contributing to efforts to improve the sustainability of the process. A pollution prevention methodology is utilized. The purpose is to provide practical options for VOC emissions reductions during the manufacturing of office furniture partitions, but the concepts can be generally applied to the wood furniture industry. Baseline VOC emissions for a typical plant are estimated using a mass balance approach. The feasibility analysis expands on a preliminary screening to identify viable pollution prevention options using realistic criteria and weightings, and is based on technical, environmental and economic considerations. The measures deemed feasible include the implementation of several best management practices, ceasing the painting of non-visible parts, switching to hot melt backwrapping glue, application of solvent recycling and modification of the mechanical clip attachment. Implementation, measurement and control plans are discussed for the measures considered feasible, which can enhance the sustainability of the manufacturing of office furniture partitions. Reducing VOC emissions using the measures identified can, in conjunction with other measures, improve the sustainability of the manufacturing process.

  15. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Erin K. Field; Robin Gerlach; Sridhar Viamajala; Laura K. Jennings; Alfred B. Cunningham; Brent M. Peyton; William A. Apel

    2011-09-01

    The reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III), can be an important aspect of remediation processes at Department of Energy (DOE) and other contaminated sites. Cellulomonas species are found at several Cr(VI) contaminated and uncontaminated locations at the DOE site in Hanford, Washington. Members of this genus have demonstrated the ability to effectively reduce Cr(VI) to Cr(III) fermentatively and therefore play a potential role in hexavalent chromium remediation at this site. Batch studies were conducted with Cellulomonas sp. strain ES6 to assess the influence of various carbon sources, iron minerals, and electron shuttling compounds on Cr(VI) reduction. These chemical species are likely to be present in these terrestrial environments during in situ bioremediation. Results indicated that there were a number of interactions between these compounds that influenced Cr(VI) reduction rates. The type of carbon source as well as the type of electron shuttle present influenced Cr(VI) reduction rates. When an electron shuttle, such as anthraquinone-2,6-disulfonate (AQDS), was present in the system, reduction rates increased significantly. Biologically reduced AQDS (AHDS) reduced Cr(VI) almost instantaneously. The presence of iron minerals and their concentrations did not significantly influence Cr(VI) reduction rates. However, strain ES6 or AQDS could directly reduce surface-associated Fe(III) to Fe(II) which was capable of reducing Cr(VI) at a near instantaneous rate. These results suggest the rate limiting step in these systems is the transfer of electrons from strain ES6 to the intermediate or terminal electron acceptor whether that is Cr(VI), Fe(III), or AQDS.

  16. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Dr Robin Gerlach; Erin K. Field; Sridhar Viamajala; Brent M. Peyton; William A. Apel; Al B. Cunningham

    2011-09-01

    Microbially reduced iron minerals can reductively transform a variety of contaminants including heavy metals, radionuclides, chlorinated aliphatics, and nitroaromatics. A number of Cellulomonas spp. strains, including strain ES6, isolated from aquifer samples obtained at the U.S. Department of Energy's Hanford site in Washington, have been shown to be capable of reducing Cr(VI), TNT, natural organic matter, and soluble ferric iron [Fe(III)]. This research investigated the ability of Cellulomonas sp. strain ES6 to reduce solid phase and dissolved Fe(III) utilizing different carbon sources and various electron shuttling compounds. Results suggest that Fe(III) reduction by and growth of strain ES6 was dependent upon the type of electron donor, the form of iron present, and the presence of synthetic or natural organic matter, such as anthraquinone-2,6-disulfonate (AQDS) or humic substances. This research suggests that Cellulomonas sp. strain ES6 could play a significant role in metal reduction in the Hanford subsurface and that the choice of carbon source and organic matter addition can allow for independent control of growth and iron reduction activity.

  17. Influence of carbon sources and electron shuttles on ferric iron reduction by Cellulomonas sp. strain ES6.

    Science.gov (United States)

    Gerlach, Robin; Field, Erin K; Viamajala, Sridhar; Peyton, Brent M; Apel, William A; Cunningham, Al B

    2011-09-01

    Microbially reduced iron minerals can reductively transform a variety of contaminants including heavy metals, radionuclides, chlorinated aliphatics, and nitroaromatics. A number of Cellulomonas spp. strains, including strain ES6, isolated from aquifer samples obtained at the U.S. Department of Energy's Hanford site in Washington, have been shown to be capable of reducing Cr(VI), TNT, natural organic matter, and soluble ferric iron [Fe(III)]. This research investigated the ability of Cellulomonas sp. strain ES6 to reduce solid phase and dissolved Fe(III) utilizing different carbon sources and various electron shuttling compounds. Results suggest that Fe(III) reduction by and growth of strain ES6 was dependent upon the type of electron donor, the form of iron present, and the presence of synthetic or natural organic matter, such as anthraquinone-2,6-disulfonate (AQDS) or humic substances. This research suggests that Cellulomonas sp. strain ES6 could play a significant role in metal reduction in the Hanford subsurface and that the choice of carbon source and organic matter addition can allow for independent control of growth and iron reduction activity.

  18. Cr(Vi) reduction capacity of activated sludge as affected by nitrogen and carbon sources, microbial acclimation and cell multiplication

    Energy Technology Data Exchange (ETDEWEB)

    Ferro Orozco, A.M., E-mail: mferro@cidca.org.ar [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Contreras, E.M.; Zaritzky, N.E. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Fac. de Ingenieria, UNLP. 47 y 1 (B1900AJJ) - La Plata (Argentina)

    2010-04-15

    The objectives of the present work were: (i) to analyze the capacity of activated sludge to reduce hexavalent chromium using different carbon sources as electron donors in batch reactors, (ii) to determine the relationship between biomass growth and the amount of Cr(VI) reduced considering the effect of the nitrogen to carbon source ratio, and (iii) to determine the effect of the Cr(VI) acclimation stage on the performance of the biological chromium reduction assessing the stability of the Cr(VI) reduction capacity of the activated sludge. The highest specific Cr(VI) removal rate (q{sub Cr}) was attained with cheese whey or lactose as electron donors decreasing in the following order: cheese whey {approx} lactose > glucose > citrate > acetate. Batch assays with different nitrogen to carbon source ratio demonstrated that biological Cr(VI) reduction is associated to the cell multiplication phase; as a result, maximum Cr(VI) removal rates occur when there is no substrate limitation. The biomass can be acclimated to the presence of Cr(VI) and generate new cells that maintain the ability to reduce chromate. Therefore, the activated sludge process could be applied to a continuous Cr(VI) removal process.

  19. Speciated OVOC and VOC emission inventories and their implications for reactivity-based ozone control strategy in the Pearl River Delta region, China.

    Science.gov (United States)

    Ou, Jiamin; Zheng, Junyu; Li, Rongrong; Huang, Xiaobo; Zhong, Zhuangmin; Zhong, Liuju; Lin, Hui

    2015-10-15

    The increasing ground-ozone (O3) levels, accompanied by decreasing SO2, NO2, PM10 and PM2.5 concentrations benefited from air pollution control measures implemented in recent years, initiated a serious challenge to control Volatile Organic Compound (VOC) emissions in the Pearl River Delta (PRD) region, China. Speciated VOC emission inventory is fundamental for estimating Ozone Formation Potentials (OFPs) to identify key reactive VOC species and sources in order to formulate efficient O3 control strategies. With the use of the latest bulk VOC emission inventory and local source profiles, this study developed the PRD regional speciated Oxygenated Volatile Organic Compound (OVOC) and VOC emission inventories to identify the key emission-based and OFP-based VOC sources and species. Results showed that: (1) Methyl alcohol, acetone and ethyl acetate were the major constituents in the OVOC emissions from industrial solvents, household solvents, architectural paints and biogenic sources; (2) from the emission-based perspective, aromatics, alkanes, OVOCs and alkenes made up 39.2%, 28.2%, 15.9% and 10.9% of anthropogenic VOCs; (3) from the OFP-based perspective, aromatics and alkenes become predominant with contributions of 59.4% and 25.8% respectively; (4) ethene, m/p-xylene, toluene, 1,2,4-trimethyl benzene and other 24 high OFP-contributing species were the key reactive species that contributed to 52% of anthropogenic emissions and up to 80% of OFPs; and (5) industrial solvents, industrial process, gasoline vehicles and motorcycles were major emission sources of these key reactive species. Policy implications for O3 control strategy were discussed. The OFP cap was proposed to regulate VOC control policies in the PRD region due to its flexibility in reducing the overall OFP of VOC emission sources in practice. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Tracking Poverty Reduction in Bhutan: Income Deprivation Alongside Deprivation in Other Sources of Happiness

    Science.gov (United States)

    Santos, Maria Emma

    2013-01-01

    This paper analyses poverty reduction in Bhutan between two points in time--2003 and 2007--from a multidimensional perspective. The measures estimated include consumption expenditure as well as other indicators which are directly (when possible) or indirectly associated to valuable functionings, namely, health, education, access to electricity,…

  1. Implementation of variance-reduction techniques for Monte Carlo nuclear logging calculations with neutron sources

    NARCIS (Netherlands)

    Maucec, M

    2005-01-01

    Monte Carlo simulations for nuclear logging applications are considered to be highly demanding transport problems. In this paper, the implementation of weight-window variance reduction schemes in a 'manual' fashion to improve the efficiency of calculations for a neutron logging tool is presented.

  2. [VOCs tax policy on China's economy development].

    Science.gov (United States)

    Liu, Chang-Xin; Wang, Yu-Fei; Wang, Hai-Lin; Hao, Zheng-Ping; Wang, Zheng

    2011-12-01

    In this paper, environmental tax was designed to control volatile organic compounds (VOCs) emissions. Computable general equilibrium (CGE) model was used to explore the impacts of environmental tax (in forms of indirect tax) on the macro-economy development at both national and sector levels. Different levels of tax were simulated to find out the proper tax rate. It is found out that imposing environmental tax on high emission sectors can cause the emission decreased immediately and can lead to negative impacts on macro-economy indicators, such as GDP (gross domestic products), total investment, total product and the whole consumption etc. However, only the government income increased. In addition, the higher the tax rate is, the more pollutants can be reduced and the worse economic effects can be caused. Consequently, it is suggested that, the main controlling policies of VOCs abatement should be mandatory orders, and low environmental tax can be implemented as a supplementary.

  3. The Reduction of Vertical Interchannel Crosstalk: The Analysis of Localisation Thresholds for Natural Sound Sources

    Directory of Open Access Journals (Sweden)

    Rory Wallis

    2017-03-01

    Full Text Available In subjective listening tests, natural sound sources were presented to subjects as vertically-oriented phantom images from two layers of loudspeakers, ‘height’ and ‘main’. Subjects were required to reduce the amplitude of the height layer until the position of the resultant sound source matched that of the same source presented from the main layer only (the localisation threshold. Delays of 0, 1 and 10 ms were applied to the height layer with respect to the main, with vertical stereophonic and quadraphonic conditions being tested. The results of the study showed that the localisation thresholds obtained were not significantly affected by sound source or presentation method. Instead, the only variable whose effect was significant was interchannel time difference (ICTD. For ICTD of 0 ms, the median threshold was −9.5 dB, which was significantly lower than the −7 dB found for both 1 and 10 ms. The results of the study have implications both for the recording of sound sources for three-dimensional (3D audio reproduction formats and also for the rendering of 3D images.

  4. Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

    Science.gov (United States)

    Hopkins, Frances; Bell, Thomas; Yang, Mingxi

    2017-04-01

    Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

  5. Influence of way of finishing furniture segments on amount emissions VOCs

    Directory of Open Access Journals (Sweden)

    Petr Čech

    2010-01-01

    Full Text Available The study deals with the influence of way of finishing furniture segments on amount emissions VOCs (volatile organic compounds. The so-called Volatile Organic Compounds (VOC are among the largest pollution sources of both the internal and external environments.VOC is defined as emission of any organic compound or a mixture thereof, with the exception of methane, whereby the compound exerts the pressure of 0.01 kPa or more at the temperature of 20 °C (293.15 K and reaches the corresponding volatility under the specific conditions of its use and can undergo photochemical reactions with nitrogen oxides when exposed to solar radiation. The effects of VOC upon environment can be described by equation: VOC + NOx + UV radiation + heat = tropospheric ozone (O3In this work there were tested MDF (medium density fibreboard coated by resin impregnated paper was used for the furniture components’ production. Next were tested compressed wood, which was used as a second material of furniture components. These both chosen materials was covered by resin impregnated paper and than sequentially finished by regular coat of finish.An attention of this study is especially put on mentioned factors and on quantity of instant and long-term VOCs emissions emitted from furniture components.The amount of emissions from furniture components, in different phases of the preparation including the resin impregnated paper coating finish, was monitored within the time intervals of 24 hours and 720 hours starting after the time of the finish preparation.The MDF (medium density fibreboard coated by resin impregnated paper was used for the furniture components´ production.A compressed wood was used as a second material of furniture components. This alternative material was covered by resin impregnated paper and than sequentially finished by regular coat of finish.

  6. [Study on the quantitative estimation method for VOCs emission from petrochemical storage tanks based on tanks 4.0.9d model].

    Science.gov (United States)

    Li, Jing; Wang, Min-Yan; Zhang, Jian; He, Wan-Qing; Nie, Lei; Shao, Xia

    2013-12-01

    VOCs emission from petrochemical storage tanks is one of the important emission sources in the petrochemical industry. In order to find out the VOCs emission amount of petrochemical storage tanks, Tanks 4.0.9d model is utilized to calculate the VOCs emission from different kinds of storage tanks. VOCs emissions from a horizontal tank, a vertical fixed roof tank, an internal floating roof tank and an external floating roof tank were calculated as an example. The consideration of the site meteorological information, the sealing information, the tank content information and unit conversion by using Tanks 4.0.9d model in China was also discussed. Tanks 4.0.9d model can be used to estimate VOCs emissions from petrochemical storage tanks in China as a simple and highly accurate method.

  7. Seasonal source contributions of tropospheric ozone over East Asia based on CMAQ-HDDM

    Science.gov (United States)

    Itahashi, Syuichi; Uno, Itsushi; Kim, Soontae

    2013-05-01

    Determining the source contributions of tropospheric ozone concentration is an important issue for East Asia, due to the dramatic and rapid increase in emissions of atmospheric pollutants. To achieve this, the higher-order decoupled direct method (HDDM), a technique for efficient calculation of sensitivities, was applied in this study. Tropospheric ozone concentrations at observation sites located in remote areas of Japan were well-reproduced by Community Multi-scale Air Quality (CMAQ) model simulations, and exhibited a maximum peak in spring, a relatively small peak in autumn and a summer minimum. This seasonal pattern is a reflection of long-range transport and chemical processes, coupled with continental-oceanic air mass exchanges forced by the East Asian monsoon. For the HDDM simulation, we focused on episodic pollution events during each season of 2007 to clarify the seasonal characteristics, and then assessed source contributions paying attention to both precursor emissions (NOx and VOC) and source regions (China, central eastern China, Korea, and Japan). An ozone-sensitive regime (NOx- or VOC-sensitive regime) was also determined based on the HDDM results. This suggested a regime over East Asia that was NOx sensitive in summer, VOC sensitive in winter, and either NOx or VOC sensitive during spring and autumn. At observation sites in remote areas of Japan, by separating the precursor contribution into NOx and VOC components of ozone production, it was found that the contribution of NOx emissions was larger than that of VOC emissions in spring, autumn, and especially summer, therefore, a reduction in NOx emissions could reduce the severity of episodes of tropospheric ozone pollution in downwind areas. Due to the strong VOC-sensitive conditions in winter, NOx emissions enabled a reduction in surface ozone concentrations. In terms of the contributions attributed to source regions, the source contribution of China was relatively high during spring, but local

  8. Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 2: Complex urban VOCs and model PM

    Directory of Open Access Journals (Sweden)

    H. E. Jeffries

    2012-12-01

    for "effect modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh", or in reacted ("Aged" complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only- and PM-only-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NOx mixture. For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemical measurements demonstrate the temporal evolution of oxidized species, with a corresponding increase in toxicity observed from exposed cells. The largest increase in gas-phase toxicity was observed in the two "Aged" VOC exposures. The largest increase in particle-phase toxicity was observed in the "Aged" VOC exposure with the addition of PM after sunset. These results are a clear demonstration that the findings from Part 1 can be extended to the complex urban oxidized environment. This further demonstrates that the atmosphere itself cannot be ignored as a source of toxic species when establishing the risks associated with exposure to PM. Because gases and PM are transported and deposited differently within the atmosphere and lungs, these results have significant consequences. In the next (and final part of the study, testing is further applied to systems with real diesel exhaust, including primary PM from a

  9. Simultaneous analysis of 28 urinary VOC metabolites using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS).

    Science.gov (United States)

    Alwis, K Udeni; Blount, Benjamin C; Britt, April S; Patel, Dhrusti; Ashley, David L

    2012-10-31

    Volatile organic compounds (VOCs) are ubiquitous in the environment, originating from many different natural and anthropogenic sources, including tobacco smoke. Long-term exposure to certain VOCs may increase the risk for cancer, birth defects, and neurocognitive impairment. Therefore, VOC exposure is an area of significant public health concern. Urinary VOC metabolites are useful biomarkers for assessing VOC exposure because of non-invasiveness of sampling and longer physiological half-lives of urinary metabolites compared with VOCs in blood and breath. We developed a method using reversed-phase ultra high performance liquid chromatography (UPLC) coupled with electrospray ionization tandem mass spectrometry (ESI/MSMS) to simultaneously quantify 28 urinary VOC metabolites as biomarkers of exposure. We describe a method that monitors metabolites of acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon-disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride and xylene. The method is accurate (mean accuracy for spiked matrix ranged from 84 to 104%), sensitive (limit of detection ranged from 0.5 to 20 ng mL(-1)) and precise (the relative standard deviations ranged from 2.5 to 11%). We applied this method to urine samples collected from 1203 non-smokers and 347 smokers and demonstrated that smokers have significantly elevated levels of tobacco-related biomarkers compared to non-smokers. We found significant (pVOC metabolites in a population exposed to volatile organics. Published by Elsevier B.V.

  10. Spatial and temporal variability in VOC levels within a commercial retail building.

    Science.gov (United States)

    Eklund, B M; Burkes, S; Morris, P; Mosconi, L

    2008-10-01

    A study was performed to characterize the concentration of dozens of volatile organic compounds (VOCs) at 10 locations within a single large building and track these concentrations over a 2-year period. The study was performed at a shopping center (strip mall) in New Jersey. A total of 130 indoor air samples were collected from 10 retail stores within the shopping center and analyzed for 60 VOCs by US EPA Method TO-15. Indoor concentrations of up to 55,100 microg/m(3) were measured for individual VOCs. The indoor/outdoor ratio (I/O) was as high as 1500 for acetone and exceeded 100 at times for various compounds, indicating that significant indoor air sources were present. A large degree of spatial variability was observed between stores within the building, with concentrations varying by three to four orders of magnitude for some compounds. The spatial variability was dependent on the proximity of the sampling locations to the indoor sources. A large degree of temporal variability also was observed for compounds emitted from indoor sources, but the temporal variability generally did not exceed two standard deviations (sigma). For compounds not emitted from indoor sources at significant rates, both the spatial and temporal variability tended to range within an order of magnitude at each location. Many cross-sectional studies have been published where the levels of volatile organic compounds (VOCs) were measured in indoor air at one or two locations for houses or offices. This study provides longitudinal data for a commercial retail building and also addresses spatial variability within the building. The data suggest that spatial and temporal variability are important considerations for compounds emitted from indoor sources. Elevated concentrations were found in retail spaces with no apparent emission sources due to their proximity to other retail spaces with emission sources.

  11. Reconciling Airborne Basin Scale Methane Flux Estimates with Ground Based Quantification of Methane and VOC Emissions from Well Pads.

    Science.gov (United States)

    Murphy, S. M.; Field, R. A.; Soltis, J.; Snare, D.; Edie, R.

    2014-12-01

    Data was collected in the Pinedale Anticline and Jonah Fields in Wyoming, both of which are among the top ten wet gas fields in the USA in terms of production. We present an estimate of total methane flux from these two gas fields derived from airborne measurements and relate this flux to ground-based measurements of methane leakage from ~50 individual well pads within the fields. The fraction of basin-wide methane flux that can be accounted for by leaks from individual well pads will be discussed as well as the fraction of methane production that is leaked. We outline the difficulties and strengths of the EPA-developed methodology, referred to as Geospatial Measurement of Air Pollution Remote Emission Quantification, that was used to determined individual well-pad leakage rates using detailed wind measurements without tracers. Often the ratio of VOC:methane concentrations is combined with a known methane flux to determine VOC emission rates. In this study, we measured the flux of volatile organic compounds (VOC) independently of methane by using a proton-transfer-reactor time-of-flight mass-spectrometer and rapid 3-D wind measurements. This allows us to distinguish sources that emit primarily VOC, those that emit a mix of VOC and methane, and those that emit primarily methane. The relationship of VOC and methane fluxes from a number of different oil and gas operations will be discussed.

  12. Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions

    Directory of Open Access Journals (Sweden)

    R. Seco

    2011-12-01

    polluted air masses receive additional biogenic VOCs emitted in the local valley by the vegetation, thus enhancing O3 formation in this forested site. The only VOC species that showed a somewhat different daily pattern were monoterpenes because of their local biogenic emission. Isoprene also followed in part the daily pattern of monoterpenes, but only in summer when its biotic sources were stronger. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources.

  13. Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions

    Science.gov (United States)

    Seco, R.; Peñuelas, J.; Filella, I.; Llusià, J.; Molowny-Horas, R.; Schallhart, S.; Metzger, A.; Müller, M.; Hansel, A.

    2011-12-01

    VOCs emitted in the local valley by the vegetation, thus enhancing O3 formation in this forested site. The only VOC species that showed a somewhat different daily pattern were monoterpenes because of their local biogenic emission. Isoprene also followed in part the daily pattern of monoterpenes, but only in summer when its biotic sources were stronger. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources.

  14. Ordered silica particles made by nonionic surfactant for VOCs sorption

    Energy Technology Data Exchange (ETDEWEB)

    Difallah, Oumaima; Hamaizi, Hadj, E-mail: hamaizimizou@yahoo.fr [University of Oran, OranMenaouer (Algeria); Amate, Maria Dolores Urena; Socias-Viciana, Maria Del Mar [University of Almeria (Spain)

    2017-07-15

    Adsorption of light organic compounds such acetone, 1-propanol and carbon dioxide was tested by using mesoporous silica materials made from non ionic surfactant with long chain and silica sources as tetraethyl orthosilicate TEOS and modified Na-X and Li-A Zeolites. X-ray powder diffraction (XRD), nitrogen adsorption-desorption analysis and scanning electron microscopy (SEM) were applied to characterize the silica particles of a variety prepared samples. Acetone, 1-propanol and CO{sub 2} adsorption at 298K was evaluated by a volumetric method and indicate a high sorption capacity of organic compounds depending essentially on the porous texture of adsorbents. An adsorption kinetic model was proposed to describe the adsorption of VOCs over template-free mesoporous silica materials. A good agreement with experimental data was found. (author)

  15. Estimated Reduction in Cancer Risk due to PAH Exposures If Source Control Measures during the 2008 Beijing Olympics Were Sustained

    Science.gov (United States)

    Jia, Yuling; Stone, Dave; Wang, Wentao; Schrlau, Jill; Tao, Shu; Massey Simonich, Staci L.

    2011-01-01

    Background The 2008 Beijing Olympic Games provided a unique case study to investigate the effect of source control measures on the reduction in air pollution, and associated inhalation cancer risk, in a Chinese megacity. Objectives We measured 17 carcinogenic polycyclic aromatic hydrocarbons (PAHs) and estimated the lifetime excess inhalation cancer risk during different periods of the Beijing Olympic Games, to assess the effectiveness of source control measures in reducing PAH-induced inhalation cancer risks. Methods PAH concentrations were measured in samples of particulate matter ≤ 2.5 μm in aerodynamic diameter (PM2.5) collected during the Beijing Olympic Games, and the associated inhalation cancer risks were estimated using a point-estimate approach based on relative potency factors. Results We estimated the number of lifetime excess cancer cases due to exposure to the 17 carcinogenic PAHs [12 priority pollutant PAHs and five high-molecular-weight (302 Da) PAHs (MW 302 PAHs)] to range from 6.5 to 518 per million people for the source control period concentrations and from 12.2 to 964 per million people for the nonsource control period concentrations. This would correspond to a 46% reduction in estimated inhalation cancer risk due to source control measures, if these measures were sustained over time. Benzo[b]fluoranthene, dibenz[a,h]anthracene, benzo[a]pyrene, and dibenzo[a,l]pyrene were the most carcinogenic PAH species evaluated. Total excess inhalation cancer risk would be underestimated by 23% if we did not include the five MW 302 PAHs in the risk calculation. Conclusions Source control measures, such as those imposed during the 2008 Beijing Olympics, can significantly reduce the inhalation cancer risk associated with PAH exposure in Chinese megacities similar to Beijing. MW 302 PAHs are a significant contributor to the estimated overall inhalation cancer risk. PMID:21632310

  16. A Novel Sensor for VOCs Using Nanostructured ZnO and MEMS Technologies

    Directory of Open Access Journals (Sweden)

    H. J. Pandya

    2012-03-01

    Full Text Available A sensor for detection of vapors of volatile organic compounds (VOCs incorporating nanostructured zinc oxide film and silicon micromachining is reported. One of the key features of the sensor is the use of nanostructured ZnO material which has been synthesized using a novel low cost process. Considerable reduction in the operating temperature of the sensor has been achieved due to the use of nanostructured ZnO material as compared to a sensor having ZnO thin film as the sensing layer. The sensor is formed on a micromachined silicon platform thereby reducing the heat loss. This resulted in reduction in power consumption. The sensor has been tested for a variety of VOCs such as: ethanol, iso-propyl alcohol and acetone. The maximum sensitivity of sensor was observed for ethanol vapors.

  17. Development of a method utilizing drum headspace VOC concentration as a waste characterization tool

    Energy Technology Data Exchange (ETDEWEB)

    Liekhus, K.J.; Gresham, G.L.; Peterson, E.S.; Rae, C.; Connolly, M.J.

    1994-12-31

    Pretest waste characterization for the bin-scale tests at the Waste Isolation Pilot Plant (WIPP) required sampling for volatile organic compounds (VOCS) from within transuranic (TRU) waste drums. Although the bin-scale tests have been postponed, the development and demonstration of accurate waste characterization methods continues. The objectives of extensive sampling of waste drums are to obtain a representative sample from each layer of confinement to identify volatile and gaseous constituents, verify process knowledge of the drum contents, and demonstrate compliance with regulatory requirements. A method to estimate the VOC concentration between layers of confinement from a single headspace sample collected beneath the drum filter of a vented waste drum is investigated. This method of characterizing the void space within a drum could eventually lead to a significant reduction in sampling time and cost. A model based on fundamental principles of transport phenomena is developed to estimate the VOC concentration throughout a waste drum based on the knowledge of the transport properties and the measured drum headspace VOC concentration. Model and experimental results are compared.

  18. Effect of heat waves on VOC emissions from vegetation and urban air quality

    Science.gov (United States)

    Churkina, G.; Kuik, F.; Lauer, A.; Bonn, B.; Butler, T. M.

    2015-12-01

    Programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account how close human and natural systems are coupled in urban areas. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Urban and sub-urban vegetation responds to ambient changes and reacts with pollutants. Neglecting this coupling may lead to unforeseen drawbacks of urban greening programs. The potential for emissions of volatile organic compounds (VOC) from vegetation combined with anthropogenic emissions to produce ozone has long been recognized. This potential increases under rising temperatures. Here we investigate how heat waves affect emissions of VOC from urban vegetation and corresponding ground-level ozone. In this study we use Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in Berlin, Germany during the 2006 heat wave. VOC emissions from vegetation are simulated with MEGAN 2.0 coupled with WRF-CHEM. Our preliminary results indicate that contribution of VOCs from vegetation to ozone formation may increase by more than twofold during the heat wave period. We highlight the importance of the vegetation for urban areas under changing climate and discuss associated tradeoffs.

  19. Local Proton Source in Electrocatalytic CO2 Reduction with [Mn(bpy-R)(CO)3 Br] Complexes.

    Science.gov (United States)

    Franco, Federico; Cometto, Claudio; Nencini, Luca; Barolo, Claudia; Sordello, Fabrizio; Minero, Claudio; Fiedler, Jan; Robert, Marc; Gobetto, Roberto; Nervi, Carlo

    2017-04-06

    The electrochemical behavior of fac-[Mn(pdbpy)(CO)3 Br] (pdbpy=4-phenyl-6-(phenyl-2,6-diol)-2,2'-bipyridine) (1) in acetonitrile under Ar, and its catalytic performances for CO2 reduction with added water, 2,2,2-trifluoroethanol (TFE), and phenol are discussed in detail. Preparative-scale electrolysis experiments, carried out at -1.5 V versus the standard calomel electrode (SCE) in CO2 -saturated acetonitrile, reveal that the process selectivity is extremely sensitive to the acid strength, producing CO and formate in different faradaic yields. A detailed spectroelectrochemical (IR and UV/Vis) study under Ar and CO2 atmospheres shows that 1 undergoes fast solvolysis; however, dimer formation in acetonitrile is suppressed, resulting in an atypical reduction mechanism in comparison with other reported MnI catalysts. Spectroscopic evidence of Mn hydride formation supports the existence of different electrocatalytic CO2 reduction pathways. Furthermore, a comparative investigation performed on the new fac-[Mn(ptbpy)(CO)3 Br] (ptbpy=4-phenyl-6-(phenyl-3,4,5-triol)-2,2'-bipyridine) catalyst (2), bearing a bipyridyl derivative with OH groups in different positions to those in 1, provides complementary information about the role that the local proton source plays during the electrochemical reduction of CO2 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Rational design of an on-site volume reduction system for source-separated urine.

    Science.gov (United States)

    Pahore, Muhammad Masoom; Ito, Ryusei; Funamizu, Naoyuki

    2010-04-01

    Human urine contains nitrogen, phosphorus and potassium, which can be applied as fertilizer in agriculture, replacing commercial fertilizer. However, owing to the low nutrient content of the urine, huge quantities must be transported to farmland to meet the nutrient demand of crops. This highly increases the transportation cost for the farmers. To address the transportation issue, a new on-site volume reduction system was tested at the laboratory scale based on water evaporation from vertical gauze sheets. A mathematical water transport model was proposed to evaluate the performance of the system. The mass transfer coefficient and the resistance of water flow through the sheet in the water transport model were obtained from the experiments. The results agreed with the simulated data, thereby confirming the proposed model. The model was then applied to the dry climate of southern Pakistan, having an air temperature of 30-40 degrees C and air humidity of 20-40%, for an 80% volume reduction of 10 L urine per day, which corresponds to a family of 10 members (average for a household in Pakistan). The findings revealed that the estimated size of the vertical sheet is 440-2060 cm2, which is only a small area for setting up the system at a household level.

  1. Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    Shoudao Huang

    2016-09-01

    Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

  2. The vapor-phase multi-stage CMD test for characterizing contaminant mass discharge associated with VOC sources in the vadose zone: Application to three sites in different lifecycle stages of SVE operations.

    Science.gov (United States)

    Brusseau, M L; Mainhagu, J; Morrison, C; Carroll, K C

    2015-08-01

    Vapor-phase multi-stage contaminant mass discharge (CMD) tests were conducted at three field sites to measure mass discharge associated with contaminant sources located in the vadose zone. The three sites represent the three primary stages of the soil vapor extraction (SVE) operations lifecycle-pre/initial-SVE, mid-lifecycle, and near-closure. A CMD of 32g/d was obtained for a site at which soil vapor SVE has been in operation for approximately 6years, and for which mass removal is currently in the asymptotic stage. The contaminant removal behavior exhibited for the vapor extractions conducted at this site suggests that there is unlikely to be a significant mass of non-vapor-phase contaminant (e.g., DNAPL, sorbed phase) remaining in the advective domains, and that most remaining mass is likely located in poorly accessible domains. Given the conditions for this site, this remaining mass is hypothesized to be associated with the low-permeability (and higher water saturation) region in the vicinity of the saturated zone and capillary fringe. A CMD of 25g/d was obtained for a site wherein SVE has been in operation for several years but concentrations and mass-removal rates are still relatively high. A CMD of 270g/d was obtained for a site for which there were no prior SVE operations. The behavior exhibited for the vapor extractions conducted at this site suggest that non-vapor-phase contaminant mass (e.g., DNAPL) may be present in the advective domains. Hence, the asymptotic conditions observed for this site most likely derive from a combination of rate-limited mass transfer from DNAPL (and sorbed) phases present in the advective domain as well as mass residing in lower-permeability ("non-advective") regions. The CMD values obtained from the tests were used in conjunction with a recently developed vapor-discharge tool to evaluate the impact of the measured CMDs on groundwater quality. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Reduction of Beam Current Noise in the FNAL Magnetron Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Bollinger, D. S. [Fermilab; Karns, P. R. [Fermilab; Tan, C. Y.

    2014-01-01

    The new FNAL Injector Line with a circular dimple magnetron ion source has been operational since December of 2013. Since the new injector came on line there have been variations in the H- beam current flattop observed near the downstream end of the linac. Several different cathode geometries including a hollow cathode suggested by Dudnikov [1] were tried. We expanded on those studies by trying mixtures ranging from 0.25%N, 99.75%H to 3%N, 97%H. The results of these studies in our test stand will be presented in this paper.

  4. Solution space reduction in the peripheral nerve source localization problem using forward field similarities

    Science.gov (United States)

    Zariffa, José; Popovic, Milos R.

    2008-06-01

    Improving our ability to localize bioelectric sources within a peripheral nerve would help us to monitor the control signals flowing to and from any limb or organ. This technology would provide a useful neuroscience tool, and could perhaps be incorporated into a neuroprosthesis interface. We propose to use measurements from a multi-contact nerve cuff to solve an inverse problem of bioelectric source localization within the peripheral nerve. Before the inverse problem can be addressed, the forward problem is solved using finite element modeling. A fine mesh improves the accuracy of the forward problem solution, but increases the number of variables to be solved for in the inverse problem. To alleviate this problem, variables corresponding to mesh elements that are not distinguishable by the measurement setup are grouped together, thus reducing the dimension of the inverse problem without impacting on the forward problem accuracy. A quantitative criterion for element distinguishability is derived using the columns of the leadfield matrix and information about the uncertainty in the measurements. Our results indicate that the number of variables in the inverse problem can be reduced by more than half using the proposed method, without having a detrimental impact on the quality of the localization.

  5. Reduction of nitrous oxide emissions from partial nitrification process by using innovative carbon source (mannitol).

    Science.gov (United States)

    Zhang, Xinwen; Wang, Xiaoqing; Zhang, Jian; Huang, Xiaoyu; Wei, Dong; Lan, Wei; Hu, Zhen

    2016-10-01

    The purpose of this study was to evaluate the effect of mannitol as carbon source on nitrogen removal and nitrous oxide (N2O) emission during partial nitrification (PN) process. Laboratory-scale PN sequencing batch reactors (SBRs) were operated with mannitol and sodium acetate as carbon sources, respectively. Results showed that mannitol could remarkably reduce N2O-N emission by 41.03%, without influencing the removal efficiency of NH4(+)-N. However, it has a significant influence on nitrite accumulation ratio (NAR) and TN removal, which were 19.97% and 13.59% lower than that in PN with sodium acetate, respectively. Microbial analysis showed that the introduction of mannitol could increase the abundance of bacteria encoding nosZ genes. In addition, anti-oxidant enzymes (T-SOD, POD and CAT) activities were significantly reduced and the dehydrogenase activity had an obvious increase in mannitol system, indicating that mannitol could alleviate the inhibition of N2O reductase (N2OR) activities caused by high NO2(-)-N concentration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Remove volatile organic compounds (VOCs) with membrane separation techniques.

    Science.gov (United States)

    Zhang, Lin; Weng, Huan-xin; Chen, Huan-lin; Gao, Cong-jie

    2002-04-01

    Membrane separation, a new technology for removing VOCs including pervaporation, vapor permeation, membrane contactor, and membrane bioreactor was presented. Comparing with traditional techniques, these special techniques are an efficient and energy-saving technology. Vapor permeation can be applied to recovery of organic solvents from exhaust streams. Membrane contactor could be used for removing or recovering VOCs from air or wastewater. Pervaporation and vapor permeation are viable methods for removing VOCs from wastewater to yield a VOC concentrate which could either be destroyed by conventional means, or be recycled for reuse.

  7. VOCs Emissions from Multiple Wood Pellet Types and Concentrations in Indoor Air.

    Science.gov (United States)

    Soto-Garcia, Lydia; Ashley, William J; Bregg, Sandar; Walier, Drew; LeBouf, Ryan; Hopke, Philip K; Rossner, Alan

    2015-09-01

    Wood pellet storage safety is an important aspect for implementing woody biomass as a renewable energy source. When wood pellets are stored indoors in large quantities (tons) in poorly ventilated spaces in buildings, such as in basements, off-gassing of volatile organic compounds (VOCs) can significantly affect indoor air quality. To determine the emission rates and potential impact of VOC emissions, a series of laboratory and field measurements were conducted using softwood, hardwood, and blended wood pellets manufactured in New York. Evacuated canisters were used to collect air samples from the headspace of drums containing pellets and then in basements and pellet storage areas of homes and small businesses. Multiple peaks were identified during GC/MS and GC/FID analysis, and four primary VOCs were characterized and quantified: methanol, pentane, pentanal, and hexanal. Laboratory results show that total VOCs (TVOCs) concentrations for softwood (SW) were statistically (p building air. Occupants of the buildings tested discussed concerns about odor and sensory irritation when new pellets were delivered. The sensory response was likely due to the aldehydes.

  8. Investigations of VOCs in and around buildings close to service stations

    Science.gov (United States)

    Hicklin, William; Farrugia, Pierre S.; Sinagra, Emmanuel

    2018-01-01

    Gas service stations are one of the major sources of volatile organic compounds in urban environments. Their emissions are expected not only to affect the ambient air quality but also that in any nearby buildings. This is particularly the case in Malta where most service stations have been built within residential zones. For this reason, it is important to understand the dispersion of volatile organic compounds (VOCs) from service stations and their infiltration into nearby residences. Two models were considered; one to predict the dispersion of VOCs in the outdoor environment in the vicinity of the service station and another one to predict the filtration of the compounds indoors. The two models can be used in tandem to predict the concentration of indoor VOCs that originate from a service station in the vicinity. Outdoor and indoor concentrations of VOCs around a service station located in a street canyon were measured, and the results used to validate the models. Predictions made using the models were found to be in general agreement with the measured concentrations of the pollutants.

  9. Indoor air quality (IAQ) assessment in a multistorey shopping mall by high-spatial-resolution monitoring of volatile organic compounds (VOC).

    Science.gov (United States)

    Amodio, M; Dambruoso, P R; de Gennaro, Gianluigi; de Gennaro, L; Loiotile, A Demarinis; Marzocca, A; Stasi, F; Trizio, L; Tutino, M

    2014-12-01

    In order to assess indoor air quality (IAQ), two 1-week monitoring campaigns of volatile organic compounds (VOC) were performed in different areas of a multistorey shopping mall. High-spatial-resolution monitoring was conducted at 32 indoor sites located in two storehouses and in different departments of a supermarket. At the same time, VOC concentrations were monitored in the mall and parking lot area as well as outdoors. VOC were sampled at 48-h periods using diffusive samplers suitable for thermal desorption. The samples were then analyzed with gas chromatography-mass spectrometry (GC-MS). The data analysis and chromatic maps indicated that the two storehouses had the highest VOC concentrations consisting principally of terpenes. These higher TVOC concentrations could be a result of the low efficiency of the air exchange and intake systems, as well as the large quantity of articles stored in these small spaces. Instead, inside the supermarket, the food department was the most critical area for VOC concentrations. To identify potential emission sources in this department, a continuous VOC analyzer was used. The findings indicated that the highest total VOC concentrations were present during cleaning activities and that these activities were carried out frequently in the food department. The study highlights the importance of conducting both high-spatial-resolution monitoring and high-temporal-resolution monitoring. The former was able to identify critical issues in environments with a complex emission scenario while the latter was useful in interpreting the dynamics of each emission source.

  10. A multi-year study of VOC emissions at a chemical waste disposal facility using mobile APCI-MS and LPCI-MS instruments.

    Science.gov (United States)

    Healy, Robert M; Chen, QingFeng; Bennett, Julie; Karellas, Nicholas S

    2018-01-01

    Real-time analysis of volatile organic compounds (VOCs) in air is useful both for source identification and emissions compliance applications. In this work, two complementary triple quadrupole mass spectrometers, fitted with an atmospheric pressure chemical ionization (APCI) and a low pressure chemical ionization (LPCI) source, respectively, were deployed simultaneously to investigate emissions of VOCs associated with an Ontario-based chemical waste disposal facility. Mobile measurements performed upwind and downwind of the facility enabled selection of the best locations for stationary sampling. Seven separate field studies were undertaken between 2000 and 2016 to assess how emissions of VOCs have changed at the site as a function of time. Up to twenty-nine VOCs were successfully identified and quantified using MS/MS in each study. Simultaneous deployment of the two mass spectrometers enabled the detection of polar VOCs including alcohols, esters, amines and ketones as well as non-polar aromatic VOCs including benzene and naphthalene in real time. Concentrations of VOCs were found to decrease significantly in the vicinity of the facility over the sixteen year period, in particular since 2007. Concentration values for each year are compared with odour thresholds and provincial guidelines and implications of future expansion of on-site solid waste landfill volumes are also discussed. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  11. Stratospheric ozone reduction and its relation to natural and man made sources

    Energy Technology Data Exchange (ETDEWEB)

    Isaksen, I.S. [Oslo Univ. (Norway). Dept. of Geophysics

    1995-12-31

    Approximately 90 % of the total ozone mass is in the stratosphere (between approximately 12 and 50 km), the rest is in the troposphere (below 12 km). The global distribution of ozone in the stratosphere and its variation over time have been studied extensively over several decades. These studies include observations by ground based instruments (e.g. Dobson instruments), instruments on airborne platforms (e.g. ozone sondes) and on satellites, and model studies which simulate the chemical and dynamical behaviour of the stratosphere. These studies have given good information about the processes which determine the ozone distribution, and how man made emissions affect the distribution. Observations have revealed that there are large year to year variations in stratospheric ozone above a particular location. These variations are difficult to predict as they are connected to irregular weather patterns. However, the observations have shown that there has been a long term decrease in stratospheric ozone on a global scale during the last two decades. The decrease has been most pronounced during the last five to six years and is seen both in the Northern and the Southern Hemispheres. The strong decrease in stratospheric ozone over the Antarctic continent, which has been observed since the mid 80s, and which has reduced the total ozone column with more than 50 % compared with earlier observations, is proven to be a result of increased man made emissions of CFCs. There are also mounting evidences that Northern Hemispheric ozone reductions observed since 1980 are connected to man made emissions of CFCs

  12. Comparison of hair reduction with three lasers and light sources: prospective, blinded and controlled study.

    Science.gov (United States)

    Sochor, Martin; Curkova, Andrea Kovacikova; Schwarczova, Zuzana; Sochorova, Ruzena; Simaljakova, Maria; Buchvald, Jozef

    2011-10-01

    The main goal of this study was to compare the hair removal efficacy of three methods: intense pulsed light (IPL), a combination of IPL and radio frequency (RF) and diode laser (810 nm). Forty participants were treated within three standardized squares on lateral sites on their legs. Each of these squares was treated twice with an interval of 4-6 weeks. The fourth square was left as a control. A blinded physician counted the hairs in each square before the first treatment and 8 months after the second treatment. Immediate and delayed side effects as well as pain scores were recorded. The mean hair count reduction achieved by the diode laser, IPL and IPL+RF was 49.90%, 39.16% and 47.15%, respectively. This study did not show any serious side effects and the number of side effects was minimal. The mean pain scores for the first and second treatments by diode laser, IPL and IPL+RF were 4.65 and 4.58, 2.43 and 2.53, and 3.95 and 4.03, respectively. At the end of the study, a free hair removal treatment for both legs was chosen by patients in the proportion 20 diode laser, 10 IPL and eight IPL+RF. The combination of RF and optical energies proved its safety and efficacy for hair removal, which is comparable with diode lasers and approximately 20% more efficient than 'pure' IPL.

  13. Analysis of Sidestream Smoke VOCs and Characterization of their Odor Profiles by VOC Preconcentrator-GC-O Techniques

    Directory of Open Access Journals (Sweden)

    Higashi N

    2014-12-01

    Full Text Available Various techniques have been employed in the analysis of volatile organic compounds (VOCs. However, these techniques are insufficient for the precise analysis of tobacco smoke VOCs because of the complexity of the operating system, system instability, or poor sensitivity. To overcome these problems, a combined system of VOC preconcentrator, gas chromatograph, and olfactometer has been developed. The performance of this new system was evaluated in the analysis of VOCs in tobacco smoke and applied to the odor profiling of sidestream smoke (SSS that has not been sufficiently investigated in the past.

  14. HYDROGEN AND VOC RETENTION IN WASTE BOXES

    Energy Technology Data Exchange (ETDEWEB)

    PACE ME; MARUSICH RM

    2008-11-21

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741, 2003) identifies derived safety controls to prevent or mitigate the risks of a single-container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes. The study evaluates the accumulation of hydrogen and VOCs within the waste box and the transport of these gases and vapors out of the waste box. To perform the analysis, there were numerous and major assumptions made regarding the generation rate and the transport pathway dimensions and their number. Since there is little actual data with regards to these assumptions, analyses of three potential configurations were performed to obtain some indication of the bounds of the issue (the concentration of hydrogen or flammable VOCs within a waste box). A brief description of each of the three cases along with the results of the analysis is summarized.

  15. Taming a Tiger in the City: Comparison of Motorized Backpack Applications and Source Reduction Against the Asian Tiger Mosquito, Aedes albopictus

    Science.gov (United States)

    2014-06-01

    Bacillus thuringiensis var. israelensis (Bti), whereas source reduction used granular formulations of the insect growth regulator methoprene (AltosidH...Bacillus thuringiensis var. israelensis (Bti) whereas source reduction used granular formulations of the insect growth regulator methoprene (AltosidH...trash cans, tarpaulins, and flower pots are nonremovable because they are in use by homeowners. Unlu et al. (2013) found that immature Ae. albopictus are

  16. Vertical characteristics of VOCs in the lower troposphere over the North China Plain during pollution periods.

    Science.gov (United States)

    Sun, Jie; Wang, Yuesi; Wu, Fangkun; Tang, Guiqian; Wang, Lili; Wang, Yinghong; Yang, Yuan

    2017-11-17

    In recent years, photochemical smog and gray haze-fog have frequently appeared over northern China. To determine the spatial distribution of volatile organic compounds (VOC) during a pollution period, tethered balloon flights were conducted over a suburban site on the North China Plain. Statistical analysis showed that the VOCs concentrations peaked at the surface, and decreased with altitude. A rapid decrease appeared from the surface to 400 m, with concnetrations of alkanes, alkenes, aromatics and halocarbons decreasing by 48.0%, 53.3%, 43.3% and 51.1%, respectively. At heights in the range of 500-1000 m, alkenes concnetrations decline by 40.2%; alkanes and halocarbons concnetrations only decreased by 24.8% and 6.4%, respectively; and aromatics increased slightly by 5.5%. High concentrations VOCs covered a higher range of height (400 m) on heavy pollution days due to lacking of diffusion power. The VOCs concentrations decreased by 50% at 200 m on light pollution days. The transport of air mass affected the composition and concentration of high-altitude VOCs, especially on lightly polluted days. These air masses originated in areas with abundant traffic and combustion sources. Reactive aromatics (kOH>20,000 ppm(-1) min(-1) and kOHlight pollution days. The contribution increased to 52% with pollution aggravated, and increased to 64% with height. The contributions of reactive aromatics were influenced by the degree of air mass aging. Under the umbrella of aging air mass, the contribution of reactive aromatics increased with height. Copyright © 2017. Published by Elsevier Ltd.

  17. Characterizing relationships between personal exposures to VOCs and socioeconomic, demographic, behavioral variables

    Science.gov (United States)

    Wang, Sheng-Wei; Majeed, Mohammed A.; Chu, Pei-Ling; Lin, Hui-Chih

    Socioeconomic and demographic factors have been found to significantly affect time-activity patterns in population cohorts that can subsequently influence personal exposures to air pollutants. This study investigates relationships between personal exposures to eight VOCs (benzene, toluene, ethylbenzene, o-xylene, m-,p-xylene, chloroform, 1,4-dichlorobenzene, and tetrachloroethene) and socioeconomic, demographic, time-activity pattern factors using data collected from the 1999-2000 National Health and Nutrition Examination Survey (NHANES) VOC study. Socio-demographic factors (such as race/ethnicity and family income) were generally found to significantly influence personal exposures to the three chlorinated compounds. This was mainly due to the associations paired by race/ethnicity and urban residence, race/ethnicity and use of air freshener in car, family income and use of dry-cleaner, which can in turn affect exposures to chloroform, 1,4-dichlorobenzene, and tetrachloroethene, respectively. For BTEX, the traffic-related compounds, housing characteristics (leaving home windows open and having an attached garage) and personal activities related to the uses of fuels or solvent-related products played more significant roles in influencing exposures. Significant differences in BTEX exposures were also commonly found in relation to gender, due to associated significant differences in time spent at work/school and outdoors. The coupling of Classification and Regression Tree (CART) and Bootstrap Aggregating (Bagging) techniques were used as effective tools for characterizing robust sets of significant VOC exposure factors presented above, which conventional statistical approaches could not accomplish. Identification of these significant VOC exposure factors can be used to generate hypotheses for future investigations about possible significant VOC exposure sources and pathways in the general U.S. population.

  18. FORMULATING ULTRA-LOW-VOC WOOD FURNITURE COATINGS

    Science.gov (United States)

    The article discusses the formulation of ultra-low volatile organic compound (VOC) wood furniture coatings. The annual U.S. market for wood coatings is about 240, 000 cu m (63 million gal). In this basis, between 57 and 91 million kg (125 and 200 million lb) of VOCs are emitted i...

  19. Are Some Fungal Volatile Organic Compounds (VOCs Mycotoxins?

    Directory of Open Access Journals (Sweden)

    Joan W. Bennett

    2015-09-01

    Full Text Available Volatile organic compounds (VOCs are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that “volatoxin” might be a useful term to describe biogenic volatile compounds with toxigenic properties.

  20. 40 CFR 52.1780 - VOC rule deficiency correction.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false VOC rule deficiency correction. 52.1780 Section 52.1780 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) North Carolina § 52.1780 VOC rule...

  1. 40 CFR 52.934 - VOC rule deficiency correction.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false VOC rule deficiency correction. 52.934 Section 52.934 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Kentucky § 52.934 VOC rule deficiency...

  2. Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

    Science.gov (United States)

    Bennett, Joan W; Inamdar, Arati A

    2015-09-22

    Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that "volatoxin" might be a useful term to describe biogenic volatile compounds with toxigenic properties.

  3. SUBSTRATE EFFECTS ON VOC EMISSIONS FROM A LATEX PAINT

    Science.gov (United States)

    The effects of two substrates -- a stainless steel plate and a gypsum board -- on the volatile organic compound (VOC) emissions from a latex paint were evaluated by environmental chamber tests. It was found that the amount of VOCs emitted from the painted stainless steel was 2 to...

  4. VOC EMISSIONS FROM AN AIR FRESHENER IN THE INDOOR ENVIRONMENT

    Science.gov (United States)

    The paper describes results of tests, conducted in the U.S. Environmental Protection Agency (EPA) large chamber facility, that investigated emissions of volatile organic compounds (VOCS) from one electrical plug-in type air freshener with pine-scented refills. VOCs were measured ...

  5. Are Some Fungal Volatile Organic Compounds (VOCs) Mycotoxins?

    Science.gov (United States)

    Bennett, Joan W.; Inamdar, Arati A.

    2015-01-01

    Volatile organic compounds (VOCs) are carbon-compounds that easily evaporate at room temperature. Toxins are biologically produced poisons; mycotoxins are those toxins produced by microscopic fungi. All fungi emit blends of VOCs; the qualitative and quantitative composition of these volatile blends varies with the species of fungus and the environmental situation in which the fungus is grown. These fungal VOCs, produced as mixtures of alcohols, aldehydes, acids, ethers, esters, ketones, terpenes, thiols and their derivatives, are responsible for the characteristic moldy odors associated with damp indoor spaces. There is increasing experimental evidence that some of these VOCs have toxic properties. Laboratory tests in mammalian tissue culture and Drosophila melanogaster have shown that many single VOCs, as well as mixtures of VOCs emitted by growing fungi, have toxic effects. This paper describes the pros and cons of categorizing toxigenic fungal VOCs as mycotoxins, uses genomic data to expand on the definition of mycotoxin, and summarizes some of the linguistic and other conventions that can create barriers to communication between the scientists who study VOCs and those who study toxins. We propose that “volatoxin” might be a useful term to describe biogenic volatile compounds with toxigenic properties. PMID:26402705

  6. Volatile Organic Compounds (VOCs) measurements onboard the HALO research aircraft during OMO-ASIA

    Science.gov (United States)

    Safadi, Layal; Neumaier, Marco; Fischbeck, Garlich; Geiger, Felix; Förster, Eric; Tomsche, Laura; Zahn, Andreas

    2017-04-01

    The objective of the OMO-Asia campaign that took place in summer 2015 was to study the free-radical chemistry at higher altitudes during the Asian summer monsoon taken over a wide area of Asia. VOC measurements (e.g. acetone, acetonitrile, benzene, and toluene) were conducted using a strongly modified instrument based on a commercial Proton-Transfer-Reaction Mass Spectrometer (PTRMS) from Ionicon. The PTRMS data are generally in good agreement with VOC measurements taken by the GC instrument from Max Planck Institute for Chemistry. In the outflow of the Monsoon plume acetone and acetonitrile volume mixing ratios (VMR) up to 1500 pptV and 180 pptV have been measured, respectively, pointing to a small contribution from biomass burning sources of which acetonitrile is an important tracer. Comparison with VOCs simulated in the atmospheric chemistry model EMAC model exhibits an underestimation (factor of 3 for acetone). The measured data were analyzed with the help of 10 days back trajectories to distinguish air mass origins. For air masses originating from North America (NA) an enhancement of 500 pptV acetone relative to the atmospheric background ( 500 pptV) can be traced back to active biogenic acetone sources in the NA boreal summer. An average enhancement of 400 pptV acetone comes from the Asian summer monsoon. Acetone - CO correlations in the monsoon relative to background air is being analyzed for further characterization and estimation of the sources.

  7. Influence of relative humidity on VOC concentrations in indoor air.

    Science.gov (United States)

    Markowicz, Pawel; Larsson, Lennart

    2015-04-01

    Volatile organic compounds (VOCs) may be emitted from surfaces indoors leading to compromised air quality. This study scrutinized the influence of relative humidity (RH) on VOC concentrations in a building that had been subjected to water damage. While air samplings in a damp room at low RH (21-22%) only revealed minor amounts of 2-ethylhexanol (3 μg/m(3)) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m(3)), measurements performed after a rapid increase of RH (to 58-75%) revealed an increase in VOC concentrations which was 3-fold for 2-ethylhexanol and 2-fold for TXIB. Similar VOC emission patterns were found in laboratory analyses of moisture-affected and laboratory-contaminated building materials. This study demonstrates the importance of monitoring RH when sampling indoor air for VOCs in order to avoid misleading conclusions from the analytical results.

  8. A systematic review of evidence and implications of spatial and seasonal variations of volatile organic compounds (VOC) in indoor human environments.

    Science.gov (United States)

    Paciência, Inês; Madureira, Joana; Rufo, João; Moreira, André; Fernandes, Eduardo de Oliveira

    2016-01-01

    Many volatile organic compounds (VOC) are classified as known or possible human carcinogens, irritants, and toxicants, and VOC exposure has been associated with asthma and other respiratory symptoms/diseases. This review summarizes recent quantitative data regarding VOC in four categories of indoor environments (schools, housing, offices, and other indoor) and compares the types and concentration levels of individual VOC that were detected, measured, and reported according to season (cold and warm). The influence of outdoor air on concentrations of indoor VOC was also assessed as ratios of indoor versus outdoor. Papers published from 2000 onward were reviewed and 1383 potentially relevant studies were identified. From these, 177 were removed after duplication, 1176 were excluded for not meeting the review criteria, and 40 were included in this review. On average, higher mean concentrations of indoor VOC were found in housing environments, in offices, and in the cold season. Volatile organic compounds are commonly present in indoor air and specific compounds, and their concentrations vary among indoor environments and seasons, indicating corresponding differences in sources (indoors and outdoors). Actions and policies to reduce VOC exposures, such as improved product labeling and consumer education, are recommended.

  9. Active Background Ion Reduction Device (ABIRD) is a Smart Enhancement to any Nanospray Source for LCMS/LCMSMS Analysis

    Science.gov (United States)

    Neveu, J.

    2010-01-01

    RP-50 A unique device has been introduced which isolates a mass spectrometer during nanospray LCMS/LCMSMS experiments from variable background ion interferences using purified room air. This device, an Active Background Ion Reduction Device (ABIRD), effectively reduces the omnipresent background ion signals typically observed (445 Da and related ion series) by an order of magnitude or more, depending on laboratory conditions. Many labs have reported an improvement in detection of low level peptides in complex mixtures with this device, as it enhances the signal to noise ratio across a broad mass range, allowing an ion trap instrument, for instance, to fill to target values with ions of interest rather than background ions. This device, available commercially only through ESI Source Solutions, Woburn, MA (http://www.esisourcesolutions.com), uses economical, long-lasting chemical filters, and has been adapted to a variety of instrument platforms.

  10. Contribution of low vapor pressure-volatile organic compounds (LVP-VOCs) from consumer products to ozone formation in urban atmospheres

    Science.gov (United States)

    Shin, Hyeong-Moo; McKone, Thomas E.; Bennett, Deborah H.

    2015-05-01

    Because recent laboratory testing indicates that some low vapor pressure-volatile organic compounds (LVP-VOC) solvents readily evaporate at ambient conditions, LVP-VOCs used in some consumer product formulations may contribute to ozone formation. The goal of this study is to determine the fraction of LVP-VOCs available for ozone formation from the use of consumer products for two hypothetical emissions. This study calculates and compares the fraction of consumed product available for ozone formation as a result of (a) volatilization to air during use and (b) down-the-drain disposal. The study also investigates the impact of different modes of releases on the overall fraction available in ambient air for ozone formation. For the portion of the LVP-VOCs volatilized to air during use, we applied a multi-compartment mass-balance model to track the fate of emitted LVP-VOCs in a multimedia urban environment. For the portion of the LVP-VOCs disposed down the drain, we used a wastewater treatment plant (WWTP) fate model to predict the emission rates of LVP-VOCs to ambient air at WWTPs or at the discharge zone of the facilities and then used these results as emissions in the multimedia urban environment model. In a WWTP, the LVP-VOCs selected in this study are primarily either biodegraded or removed via sorption to sludge depending on the magnitude of the biodegradation half-life and the octanol-water partition coefficient. Less than 0.2% of the LVP-VOCs disposed down the drain are available for ozone formation. In contrast, when the LVP-VOC in a consumer product is volatilized from the surface to which it has been applied, greater than 90% is available for photochemical reactions either at the source location or in the downwind areas. Comparing results from these two modes of releases allows us to understand the importance of determining the fraction of LVP-VOCs volatilized versus disposed down the drain when the product is used by consumers. The results from this study

  11. Hydrogenated Graphenes by Birch Reduction: Influence of Electron and Proton Sources on Hydrogenation Efficiency, Magnetism, and Electrochemistry.

    Science.gov (United States)

    Eng, Alex Yong Sheng; Sofer, Zdeněk; Huber, Štěpán; Bouša, Daniel; Maryško, Miroslav; Pumera, Martin

    2015-11-16

    Interest in chemical functionalisation of graphenes today is largely driven by associated changes to its physical and material properties. Functionalisation with hydrogen was employed to obtain hydrogenated graphenes (also termed graphane if fully hydrogenated), which exhibited properties including fluorescence, magnetism and a tuneable band gap. Although the classical Birch reduction has been employed for hydrogenation of graphite oxide, variation exists between the choice of alkali metals and alcohols/water as quenching agents. A systematic study of electron (Li, Na, K, Cs) and proton sources (tBuOH, iPrOH, MeOH, H2O) has been performed to identify optimal conditions. The proton source exerted a great influence on the resulting hydrogenation with water and out-performed alcohols, and the lowest carbon-to-hydrogen ratio was observed with sodium and water with composition of C1.4H1O0.3. Although ferromagnetism at room temperature correlates well with increasing hydrogen concentrations, small contributions from trace iron impurities cannot be completely eliminated. In contrast, hydrogenated graphenes exhibit a significant paramagnetic moment at low temperatures that has no correlation with impurities, and therefore, originates from the carbon system. This is in comparison to graphene, which is strongly diamagnetic, and concentrations of paramagnetic centres in hydrogenated graphenes are one order of magnitude larger than that in graphite. Nonetheless, hydrogenation over a particular level might also excessively disrupt intrinsic sp(2) conjugation, resulting in unintended reduction of electrochemical properties. This was observed with heterogeneous electron-transfer rates and it was postulated that hydrogenated graphenes should generally have high defect densities, but only moderately high hydrogenation, should they be employed as electrode materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Nieuwsgaring in Batavia tijdens de VOC

    Directory of Open Access Journals (Sweden)

    Adrienne Zuiderweg

    2010-12-01

    Full Text Available  The board members of the Dutch East India Company (1602-1795, the Heren Zeventien, promulgated various decrees in which they forbade to bring out information regarding their colonies in the Dutch East Indies and Batavia in letters, manuscripts and printed matter. But in Batavia some inventive Company servants and even staff members got around these regulations, as did some printers in Holland. They published newspapers like Bataviase Nouvelles and Vendu-Nieuws, and also the specialized journal Verhandelingen van het Bataviaasch Genootschap. The initiators of this journal joined hands with the Dutch world of learning and its journals. This article provides an overview of early journalism in the Dutch East Indies and thus contributes to the reconstruction of the literary and cultural climate in Batavia at the time of the VOC.

  13. Characterizations of volatile organic compounds (VOCs) from vehicular emissions at roadside environment: The first comprehensive study in Northwestern China

    Science.gov (United States)

    Li, Bowei; Ho, Steven Sai Hang; Xue, Yonggang; Huang, Yu; Wang, Liqin; Cheng, Yan; Dai, Wenting; Zhong, Haobin; Cao, Junji; Lee, Shuncheng

    2017-07-01

    Vehicular emission (VE) is one of the important anthropogenic sources for ground-level volatile organic compounds (VOCs) in both urban and suburban areas. A first comprehensive campaign was conducted at an urban roadside in Xi'an, China in summer, 2016. A total of 57 VOCs, as known as critical surface ozone (O3) precursors, and other trace gases were measured simultaneously during the sampling period. Iso-pentane, a tracer of gasoline evaporation, was the most abundant VOC in the roadside samples, followed by isobutane and benzene, attributed to the largest composition (∼70%) of gasoline-fueled vehicles on the road. The molar ratio of toluene/benzene (T/B) in our study (0.36) is far lower than the range reported in other cities, indicating the stronger contributions from diesel emissions. The results of source apportionment achieved with positive matrix factorization (PMF) receptor model were highly consistent with the vehicles compositions, strongly evidenced that the precise characterization of the VE sources from those marker species. The degrees of individual compound contributed to O3 production were weighed by ozone formation potential (OFP). Propylene (20%), 1-butene (11%) and iso-pentane(10%) were the top three contributors at the roadside. The information of this study complements the VOCs database regarding to the VE sources in Northwestern China.

  14. Catalysts for cleaner combustion of coal, wood and briquettes sulfur dioxide reduction options for low emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.V. [Global Environmental Solutions, Inc., Morton Grove, IL (United States)

    1995-12-31

    Coal fired, low emission sources are a major factor in the air quality problems facing eastern European cities. These sources include: stoker-fired boilers which feed district heating systems and also meet local industrial steam demand, hand-fired boilers which provide heat for one building or a small group of buildings, and masonary tile stoves which heat individual rooms. Global Environmental Systems is marketing through Global Environmental Systems of Polane, Inc. catalysts to improve the combustion of coal, wood or fuel oils in these combustion systems. PCCL-II Combustion Catalysts promotes more complete combustion, reduces or eliminates slag formations, soot, corrosion and some air pollution emissions and is especially effective on high sulfur-high vanadium residual oils. Glo-Klen is a semi-dry powder continuous acting catalyst that is injected directly into the furnace of boilers by operating personnel. It is a multi-purpose catalyst that is a furnace combustion catalyst that saves fuel by increasing combustion efficiency, a cleaner of heat transfer surfaces that saves additional fuel by increasing the absorption of heat, a corrosion-inhibiting catalyst that reduces costly corrosion damage and an air pollution reducing catalyst that reduces air pollution type stack emissions. The reduction of sulfur dioxides from coal or oil-fired boilers of the hand fired stoker design and larger, can be controlled by the induction of the Glo-Klen combustion catalyst and either hydrated lime or pulverized limestone.

  15. New device for time-averaged measurement of volatile organic compounds (VOCs)

    Energy Technology Data Exchange (ETDEWEB)

    Santiago Sánchez, Noemí; Tejada Alarcón, Sergio; Tortajada Santonja, Rafael; Llorca-Pórcel, Julio, E-mail: julio.llorca@aqualogy.net

    2014-07-01

    Contamination by volatile organic compounds (VOCs) in the environment is an increasing concern since these compounds are harmful to ecosystems and even to human health. Actually, many of them are considered toxic and/or carcinogenic. The main sources of pollution come from very diffuse focal points such as industrial discharges, urban water and accidental spills as these compounds may be present in many products and processes (i.e., paints, fuels, petroleum products, raw materials, solvents, etc.) making their control difficult. The presence of these compounds in groundwater, influenced by discharges, leachate or effluents of WWTPs is especially problematic. In recent years, law has been increasingly restrictive with the emissions of these compounds. From an environmental point of view, the European Water Framework Directive (2000/60/EC) sets out some VOCs as priority substances. This binding directive sets guidelines to control compounds such as benzene, chloroform, and carbon tetrachloride to be at a very low level of concentration and with a very high frequency of analysis. The presence of VOCs in the various effluents is often highly variable and discontinuous since it depends on the variability of the sources of contamination. Therefore, in order to have complete information of the presence of these contaminants and to effectively take preventive measures, it is important to continuously control, requiring the development of new devices which obtain average concentrations over time. As of today, due to technical limitations, there are no devices on the market that allow continuous sampling of these compounds in an efficient way and to facilitate sufficient detection limits to meet the legal requirements which are capable of detecting very sporadic and of short duration discharges. LABAQUA has developed a device which consists of a small peristaltic pump controlled by an electronic board that governs its operation by pre-programming. A constant flow passes

  16. Sources and Seasonality of Volatile Organic Compounds in the Northern Front Range Metropolitan Area

    Science.gov (United States)

    Abeleira, A.; Pollack, I. B.; Sive, B. C.; Zaragoza, J.; Lindaas, J.; Fischer, E. V.; Farmer, D.

    2016-12-01

    The Northern Front Range Metropolitan Area (NFRMA) of Colorado, with a growing population of over 3 million, was deemed an ozone (O3) nonattainment area (NAA) in 2008 despite continued work on NOx reductions. Ground-level O3 is produced from photochemical catalytic cycles initiated by the OH oxidation of volatile organic compounds (VOCs), and propagated through reactions involving peroxy (HO2+RO2) and NOx (NO + NO2) radicals. We measured a suite of speciated VOCs during two 8-week deployments (March-May 2015, July-September 2015) at the Boulder Atmospheric Observatory in Erie, CO. The spring deployment overlapped with the NOAA SONGNEX (Shale Oil and Natural Gas Nexus) campaign. The BAO site lies at an urban-rural interface in the NFRMA with multiple urban centers surrounding the site, a major interstate highway within 2 miles, local suburban development in Erie, agricultural operations in the surrounding counties, and recent rapid expansion of oil and gas development in adjacent Weld County. VOCs were measured hourly with a custom-built online gas chromatography system along with measurements of O3, NOx, PAN, CO, and CH4. VOC measurements included C2-C8 hydrocarbons (NMHCs), C1-C5 alkyl nitrates, C1-C2 halocarbons, and several oxygenated species (OVOCs: methyl ethyl ketone, acetone, acetaldehyde). Using Positive Matrix Factorization (PMF) we have identified four distinct VOC sources in the spring and five in the summer: 1) Oil and Natural Gas (ONG, e.g. C2 - C5 alkanes), 2) Traffic (e.g. ethyne & aromatics), 3) Background species (e.g. long-lived halogenated species), 4) Secondary production (e.g. C3-C5 alkyl nitrates & OVOCs), and for summer 5) Biogenic (e.g. isoprene). Using the source factors generated from the PMF analysis we calculated the VOC reactivity (VOCr) of each source. For both seasons, the ONG factor dominates VOCr in the mornings. In spring afternoons, a combination of background species and secondary products make up a large percentage of VOCr as

  17. Contribution of evaporative emissions from gasoline vehicles toward total VOC emissions in Japan.

    Science.gov (United States)

    Yamada, Hiroyuki

    2013-04-01

    The features of evaporative emissions from gasoline vehicles were examined. One potential source of evaporative emissions is mainly the so-called sigh of a fuel tank, which is a function of the daily temperature change and the volume not occupied by fuel. A theoretical equation was proposed for estimating the fuel vapor generation. It reproduced observed features well but underestimated the absolute values obtained in the experimental results. The widely used semi-empirical Reddy equation overestimates the results. The performance of a carbon canister was also evaluated. More than 95% of fuel vapor generation was trapped by the carbon canister. However, the canister worked for only one day because it adsorbed more VOC than that contained in the sigh alone. To estimate the evaporative emissions in the real world, the fuel tank temperature change while a car was parked in an outside car park was monitored and was found to be almost the same as the change in ambient air temperature; no other weather conditions had any effect. According to the findings in this study and data on frequency of car use, the annual amount of evaporative emissions from gasoline vehicles in Japan was estimated to be 4.6% of the total VOC emissions in Japan, making it the 6th-highest source of VOC. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Non-Destructive Evaluation of Historical Paper Based on pH Estimation from VOC Emissions

    Directory of Open Access Journals (Sweden)

    Boris Pihlar

    2007-12-01

    Full Text Available Volatile organic compounds (VOCs emitted from materials during degradationcan be a valuable source of information. In this work, the emissions of furfural and aceticacid from cellulose were studied using solid-phase micro-extraction (SPME incombination with gas chromatography-mass spectrometry. Two sampling techniques wereemployed: static headspace sampling using SPME for 1 h at 40 oC after 18-h samplepreparation at 80 oC in a closed glass vial, and contact SPME in a stack of paper (or abook. While a number of VOCs are emitted from paper under conditions of natural oraccelerated degradation, two compounds were confirmed to be of particular diagnosticvalue: acetic acid and furfural. The emissions of furfural are shown to correlate with pH ofthe cellulosic environment. Since pH is one of the most important parameters regardingdurability of this material, the developed method could be used for non-destructiveevaluation of historical paper.

  19. Determination of radon exhalation from construction materials using VOC emission test chambers.

    Science.gov (United States)

    Richter, M; Jann, O; Kemski, J; Schneider, U; Krocker, C; Hoffmann, B

    2013-10-01

    The inhalation of (222) Rn (radon) decay products is one of the most important reasons for lung cancer after smoking. Stony building materials are an important source of indoor radon. This article describes the determination of the exhalation rate of stony construction materials by the use of commercially available measuring devices in combination with VOC emission test chambers. Five materials - two types of clay brick, clinker brick, light-weight concrete brick, and honeycomb brick - generally used for wall constructions were used for the experiments. Their contribution to real room concentrations was estimated by applying room model parameters given in ISO 16000-9, RP 112, and AgBB. This knowledge can be relevant, if for instance indoor radon concentration is limited by law. The test set-up used here is well suited for application in test laboratories dealing with VOC emission testing. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Characteristics of volatile organic compounds (VOCs) from the evaporative emissions of modern passenger cars

    Science.gov (United States)

    Yue, Tingting; Yue, Xin; Chai, Fahe; Hu, Jingnan; Lai, Yitu; He, Liqang; Zhu, Rencheng

    2017-02-01

    Volatile organic compounds (VOCs) from vehicle evaporative emissions contribute substantially to photochemical air pollution. Yet, few studies of the characteristics of VOCs emitted from vehicle evaporative emissions have been published. We investigate the characteristics of 57 VOCs in hot soak, 24 h diurnal and 48 h diurnal emissions by applying the Sealed Housing Evaporative Determination unit (SHED) test to three modern passenger cars (one US Tier 2 and two China IV vehicles) using two different types of gasoline. The characteristics of the VOCs from the hot soak, 24 h diurnal and 48 h diurnal emissions were different due to their different emission mechanisms. In the hot soak emissions, toluene, isopentane/n-pentane, and 2,2,4-trimethylpentane were dominant species. In the 24 h and 48 h diurnal emissions, isopentane and n-pentane were dominant species. Toluene was the third most dominant component in the 24 h diurnal emissions but decreased by a mass of 42%-80% in the 48 h diurnal emissions. In the hot soak, 24 h diurnal and 48 h diurnal emissions, alkanes were generally the dominant hydrocarbons, followed by aromatics and olefins. However, owing to different evaporative emission mechanisms, the weight percentages of the aromatic hydrocarbons decreased and the weight percentages of the alkanes increased from the hot soak test to the 24 h diurnal and 48 h diurnal tests for each vehicle. The dominant contributors to the ozone formation potentials (OFPs) were also different in the hot soak, 24 h diurnal and 48 h diurnal emissions. The OFPs (g O3/g VOC) of the hot soak emissions were higher than those of the 24 h and 48 h diurnal emissions. In addition, the combined effect of decreasing the olefin and aromatic contents of gasoline on vehicle evaporative emissions was investigated. The aromatics all decreased substantially in the hot soak, 24 h and 48 h diurnal emissions, and the total masses of the VOCs and OFPs decreased, with the greatest reduction occurring in

  1. Quantifying VOC emissions for the strategic petroleum reserve.

    Energy Technology Data Exchange (ETDEWEB)

    Knowlton, Robert G.; Lord, David L.

    2013-06-01

    A very important aspect of the Department of Energys (DOEs) Strategic Petroleum Reserve (SPR) program is regulatory compliance. One of the regulatory compliance issues deals with limiting the amount of volatile organic compounds (VOCs) that are emitted into the atmosphere from brine wastes when they are discharged to brine holding ponds. The US Environmental Protection Agency (USEPA) has set limits on the amount of VOCs that can be discharged to the atmosphere. Several attempts have been made to quantify the VOC emissions associated with the brine ponds going back to the late 1970s. There are potential issues associated with each of these quantification efforts. Two efforts were made to quantify VOC emissions by analyzing VOC content of brine samples obtained from wells. Efforts to measure air concentrations were mentioned in historical reports but no data have been located to confirm these assertions. A modeling effort was also performed to quantify the VOC emissions. More recently in 2011- 2013, additional brine sampling has been performed to update the VOC emissions estimate. An analysis of the statistical confidence in these results is presented here. Arguably, there are uncertainties associated with each of these efforts. The analysis herein indicates that the upper confidence limit in VOC emissions based on recent brine sampling is very close to the 0.42 ton/MMB limit used historically on the project. Refining this estimate would require considerable investment in additional sampling, analysis, and monitoring. An analysis of the VOC emissions at each site suggests that additional discharges could be made and stay within current regulatory limits.

  2. Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    C. Huang

    2011-05-01

    Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.

  3. Gap-filling strategies for annual VOC flux data sets.

    Science.gov (United States)

    Bamberger, I; Hörtnagl, L; Walser, M; Hansel, A; Wohlfahrt, G

    2013-11-01

    Up to now the limited knowledge about the exchange of volatile organic compounds (VOCs) between the biosphere and the atmosphere is one of the factors which hinders more accurate climate predictions. Complete long-term flux data sets of several VOCs to quantify the annual exchange and validate recent VOC models are basically not available. In combination with long-term VOC flux measurements the application of gap-filling routines is inevitable in order to replace missing data and make an important step towards a better understanding of the VOC ecosystem-atmosphere exchange on longer time scales. We performed VOC flux measurements above a mountain meadow in Austria during two complete growing seasons (from snowmelt in spring to snow reestablishment in late autumn) and used this data set to test the performance of four different gap-filling routines, mean diurnal variation (MDV), mean gliding window (MGW), look up tables (LUT) and linear interpolation (LIP), in terms of their ability to replace missing flux data in order to obtain reliable VOC sums. According to our findings the MDV routine was outstanding with regard to the minimization of the gap-filling error for both years and all quantified VOCs. The other gap-filling routines, which performed gap-filling on 24 h average values, introduced considerably larger uncertainties. The error which was introduced by the application of the different filling routines increased linearly with the number of data gaps. Although average VOC fluxes measured during the winter period (complete snow coverage) were close to zero, these were highly variable and the filling of the winter period resulted in considerably higher uncertainties compared to the application of gap-filling during the measurement period. The annual patterns of the overall cumulative fluxes for the quantified VOCs showed a completely different behavior in 2009, which was an exceptional year due to the occurrence of a severe hailstorm, compared to 2011. Methanol

  4. Colorimetric Polydiacetylene-Aerogel Detector for Volatile Organic Compounds (VOCs).

    Science.gov (United States)

    Dolai, Susmita; Bhunia, Susanta Kumar; Beglaryan, Stella S; Kolusheva, Sofiya; Zeiri, Leila; Jelinek, Raz

    2017-01-25

    A new hybrid system comprising polydiacetylene (PDA), a chromatic conjugated polymer, embedded within aerogel pores has been constructed. The PDA-aerogel powder underwent dramatic color changes in the presence of volatile organic compounds (VOCs), facilitated through infiltration of the gas molecules into the highly porous aerogel matrix and their interactions with the aerogel-embedded PDA units. The PDA-aerogel composite exhibited rapid color/fluorescence response and enhanced signals upon exposure to low VOC concentrations. Encapsulation of PDA derivatives displaying different headgroups within the aerogel produced distinct VOC-dependent color transformations, forming a PDA-aerogel "artificial nose".

  5. VOC and HAP recovery using ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Michael R. Milota : Kaichang Li

    2007-05-29

    During the manufacture of wood composites, paper, and to a lesser extent, lumber, large amounts of volatile organic compounds (VOCs) such as terpenes, formaldehyde, and methanol are emitted to air. Some of these compounds are hazardous air pollutants (HAPs). The air pollutants produced in the forest products industry are difficult to manage because the concentrations are very low. Presently, regenerative thermal oxidizers (RTOs and RCOs) are commonly used for the destruction of VOCs and HAPs. RTOs consume large amounts of natural gas to heat air and moisture. The combustion of natural gas generates increased CO2 and NOx, which have negative implications for global warming and air quality. The aforementioned problems are addressed by an absorption system containing a room-temperature ionic liquid (RTIL) as an absorbent. RTILs are salts, but are in liquid states at room temperature. RTILs, an emerging technology, are receiving much attention as replacements for organic solvents in industrial processes with significant cost and environmental benefits. Some of these processes include organic synthesis, extraction, and metal deposition. RTILs would be excellent absorbents for exhausts from wood products facilities because of their unique properties: no measurable vapor pressure, high solubility of wide range of organic compounds, thermal stability to 200°C (almost 400°F), and immisciblity with water. Room temperature ionic liquids were tested as possible absorbents. Four were imidizolium-based and were eight phosphonium-based. The imidizolium-based ionic liquids proved to be unstable at the conditions tested and in the presence of water. The phosphonium-based ionic liquids were stable. Most were good absorbents; however, cleaning the contaminates from the ionic liquids was problematic. This was overcome with a higher temperature (120°C) than originally proposed and a very low pressure (1 kPa. Absorption trials were conducted with tetradecy

  6. Multipass membrane air-stripping (MAS) for removing volatile organic compounds (VOCs) from surfactant micellar solutions.

    Science.gov (United States)

    Cheng, Hefa; Hu, Yuanan; Luo, Jian; Sabatini, David A

    2009-10-30

    Air-stripping is one of the most effective technologies for removing volatile organic compounds (VOCs) from surfactant solutions, although the presence of surfactant poses some unique challenges. This study evaluated the effect of a mixed surfactant system on the apparent Henry's law constant of tetrachloroethylene (PCE) and the efficiency of PCE removal from surfactant solutions using a lab-scale hollow fiber membrane contactor. Results show that the presence of surfactant significantly reduced the apparent Henry's law constant of PCE, and the reduction was proportional to the total surfactant concentration. PCE removal efficiency by membrane air-stripping (MAS) decreased as the surfactant system transitioned from solubilization to supersolubilization. Besides significantly reducing the apparent volatility of VOCs, the presence of surfactant brings additional mass transfer resistance in air-stripping, which makes it difficult to achieve high levels of contaminant removal, even at very high air/liquid (A/L) ratios. In contrast, multipass/multistage MAS operated at low A/L ratios could achieve near 100% contaminant removal because of less mass transfer limitation during each stripping pass/stage. Experimental results, together with model calculations demonstrate multipass (and multistage) air-stripping as a cost-effective alternative for removing VOCs from surfactant micellar solutions compared to the options of using large air strippers or operating at high A/L ratios.

  7. Surface emission determination of volatile organic compounds (VOC) from a closed industrial waste landfill using a self-designed static flux chamber.

    Science.gov (United States)

    Gallego, E; Perales, J F; Roca, F J; Guardino, X

    2014-02-01

    Closed landfills can be a source of VOC and odorous nuisances to their atmospheric surroundings. A self-designed cylindrical air flux chamber was used to measure VOC surface emissions in a closed industrial landfill located in Cerdanyola del Vallès, Catalonia, Spain. The two main objectives of the study were the evaluation of the performance of the chamber setup in typical measurement conditions and the determination of the emission rates of 60 different VOC from that industrial landfill, generating a valuable database that can be useful in future studies related to industrial landfill management. Triplicate samples were taken in five selected sampling points. VOC were sampled dynamically using multi-sorbent bed tubes (Carbotrap, Carbopack X, Carboxen 569) connected to SKC AirCheck 2000 pumps. The analysis was performed by automatic thermal desorption coupled with a capillary gas chromatograph/mass spectrometry detector. The emission rates of sixty VOC were calculated for each sampling point in an effort to characterize surface emissions. To calculate average, minimum and maximum emission values for each VOC, the results were analyzed by three different methods: Global, Kriging and Tributary area. Global and Tributary area methodologies presented similar values, with total VOC emissions of 237 ± 48 and 222 ± 46 g day(-1), respectively; however, Kriging values were lower, 77 ± 17 gd ay(-1). The main contributors to the total emission rate were aldehydes (nonanal and decanal), acetic acid, ketones (acetone), aromatic hydrocarbons and alcohols. Most aromatic hydrocarbon (except benzene, naphthalene and methylnaphthalenes) and aldehyde emission rates exhibited strong correlations with the rest of VOC of their family, indicating a possible common source of these compounds. B:T ratio obtained from the emission rates of the studied landfill suggested that the factors that regulate aromatic hydrocarbon distributions in the landfill emissions are different from the ones

  8. Middle East emissions of VOCs estimated using OMI HCHO observations and the MAGRITTE regional model

    Science.gov (United States)

    Müller, Jean-Francois; Stavrakou, Trisevgeni; Bauwens, Maite; De Smedt, Isabelle; Van Roozendael, Michel

    2017-04-01

    major VOC source in summertime throughout the "Fertile Crescent" from the Nile Valley to Iraq. Anthropogenic emissions from many large cities (e.g. Bagdad and Cairo) as well as from known oil extraction/refining/handling sites are well detected, while other cities (such as Riyadh) are elusive.

  9. Commuter exposure to aromatic VOCs in public transportation modes in Hong Kong.

    Science.gov (United States)

    Lau, Wai-Lun; Chan, Lo-Yin

    2003-06-01

    This study investigated commuter exposure to aromatic volatile organic compounds (VOCs) in different commuting microenvironments. In Hong Kong, more than 90% of the local citizens rely on public transport facilities in their daily commutes. During five winter months in late 2001 and early 2002, in-vehicle monitoring was performed in nine popular public transportation modes: tram, public light bus, air-conditioned bus, non-air-conditioned bus, taxi, ferry and three railway systems (Mass Transit Railway-MTR, Kowloon-Canton Railway-KCR and Light Rail Transit-LRT). These transports were grouped into three categories: railway transport, roadway transport and marine transport. Air samples of benzene, toluene, ethylbenzene and m/p/o-xylene were collected by canisters and analysed by gas chromatography and mass selective detector technique. Results indicated that the in-vehicle VOC exposure levels were greatly influenced by the mode of transport. For benzene, mean concentration ranged from 4.8 to 6.1 microg x m(-3) in roadway transports, 3.0-3.8 microg x m(-3) in railway transports and it was 2.1 microg x m(-3) in ferry. Regardless of the results in MTR and air-conditioned buses, the VOC levels in roadway transport were the highest and was followed by railway transport. The exposure levels in marine transport were the lowest. The TEX concentrations were found to be substantially higher in air-conditioned buses and MTR trains than in other transports, suggesting the existence of additional solvent-related sources in their vehicle interiors. Measurements in non-air-conditioned double deck vehicles indicate that there was slightly higher VOC levels in the lower deck than in the upper deck microenvironment. The average upper to lower deck exposure ratio ranged from 0.79 to 0.87 in trams and 0.78-0.83 in non-air-conditioned buses, depending on the compound of concern. The VOC exposure levels of public transport commuters in Hong Kong are far lower than those in most oversea

  10. Characterization and health risk assessment of VOCs in occupational environments in Buenos Aires, Argentina

    Science.gov (United States)

    Colman Lerner, J. E.; Sanchez, E. Y.; Sambeth, J. E.; Porta, A. A.

    2012-08-01

    To detect volatile organic compounds (VOCs) in indoor air in small enterprises in La Plata city and surrounding areas, sampling was conducted using passive diffusion monitors (3M-3500) and analysis of the samples were performed byCG-FID. Analytic methodology was optimized for 23 VOCs (n-alkanes, cycloalkanes, aromatic and chlorinated compounds, ketones and terpenes compounds) by determining the recovery factor and detection limit for each analyte. Different recovery values were obtained by desorbing with a mixture of dichloromethane: methanol (50:50), with a standard deviation lower than 5%. Enterprise analyzed included chemical analysis laboratories, sewing workrooms, electromechanical repair and car painting centers, take away food shops, and a photocopy center. The highest levels of VOCs were found to be in electromechanical repair and car painting centers (hexane, BTEX, CHCl3, CCl4) followed by chemical analysis laboratories and sewing workrooms. Cancer and noncancer risks were assessed using conventional approaches (HQ and LCR, US EPA) using the benzene, trichloroethylene, chloroform for cancer risk, and toluene, xylene and n-hexane, for noncancer risks as markers. The results showed different LCR for benzene and trichloroethylene between the different indoor environments analyzed (electromechanical repair and car painting center ≫ others) and chloroform (laboratory > others), but comparing with the results obtained by other research, are in similar order of magnitude for equivalents activities. Similar finding were founded for HQ. Comparing these results with the worker protection legislation the electromechanical repair and car painting center and chemical analysis laboratories are close to the limits advised by OSHA and ACGIH. These facts show the importance of the use of abatement technologies for the complete reduction of VOCs levels, to mitigate their impact in the worker's health and their venting to the atmosphere.

  11. Ozone response to precursor controls in very complex terrains: Use of photochemical indicators to assess O3-NOx-VOC sensitivity in the northeastern Iberian Peninsula

    Science.gov (United States)

    JiméNez, Pedro; Baldasano, José M.

    2004-10-01

    The kinetics of ozone (O3) chemistry and its two main precursors, nitrogen oxides (NOx) and volatile organic compounds (VOC), represents an important field of uncertainty in atmospheric chemistry and photochemical modeling. This uncertainty affects the design of control strategies to reduce tropospheric O3 production. The effect of controlling ozone precursors on sensitivity regimes was evaluated by performing simulations with MM5-EMICAT2000-CMAQ model to represent O3 formation in the northeastern Iberian Peninsula with baseline emission rates for VOC and NOx, and reducing anthropogenic VOC and NOx emissions on a 35%. Three different scenarios were considered in order to assess chemical sensitivity in urban, industrial, and background domains. Areas downwind of the city of Barcelona benefit from NOx reductions (reduction of 10 ppb in ground-level O3), while the same reduction causes an important increment of O3 in Barcelona (9 ppb) and the area downwind of Tarragona (18 ppb), with a high industrial influence. The city of Barcelona benefits from VOC reductions (10 ppb of O3) as well as the industrial zone of Alcover (20 ppb). The rest of the domain is practically insensitive to VOC reductions. Diverse photochemical species derived from the air quality model were used as indicators in order to establish the chemical sensitivity regime existing in the areas, analyzing whether O3 values reacted consistently to similar changes in emissions. Results showed that NOy (total reactive nitrogen) and O3/NOy are the indicators involving a lower uncertainty when assessing sensitivity, according to the narrow transition regime between NOx- and VOC-sensitive chemistry and the low uncertainty observed. Indicators performed better in VOC-sensitive than in NOx-sensitive domains. H2O2- and HNO3- derived indicators entailed higher uncertainties since transition regimes between NOx and VOC sensitivity covered a wide range. The extent of reaction also performed as a good indicator to

  12. A deeper look at the response of oxygenated and non oxygenated VOC to mid-term drought over the seasonal cycle: the case study of a drought-resistant species

    Science.gov (United States)

    Saunier, Amelie; Ormeño Lafuente, Elena; Wortham, Henri; Temime-Roussel, Brice; Fernandez, Catherine

    2015-04-01

    At the end of this century, climatic models plan an intensification of summer drought in the Mediterranean area due to a 30% rain reduction and a temperature rise of 3.4 °C. Plants respond to drought by modifying their primary (growth) and their secondary metabolism, the later being partly represented by volatile organic compound (VOC) emissions, such as terpenes. With drought, oxygenated and non oxygenated terpene emissions have been observed to increase, decrease or remain unchanged according to drought severity and vegetal model. By contrast, the response of non-terpenic oxygenated compounds to drought has been poorly studied. The aim of this study is to determine the potential impact of a two-year drought period on the full screen of VOC released by Q. pubescens, with a focus on both isoprene and methanol, issued from plant anabolism , and the numerous highly volatile oxygenated VOC, issued from plant catabolism (i.e. issued from oxidation of isoprene or methanol). A 70 years-old Downy oak forest (Quercus pubescens), highly resistant to drought stress, was selected as model ecosystem since it is well widespread in Southern France occupying 321 000 ha. Downy oak also represents the major source of isoprene emissions in the Mediterranean area and, unlike the other major Quercus sp. of the region (i.e. Quercus ilex, a monoterpene emitter) the impact of watering withholding over years has never been tackled. The study was performed at the experimental platform of O3HP (Oak Observatory at Observatoire de Haute Provence) in Southern France which is equipped with both a rain exclusion (by 30 %) and a rain addition structure (simulating the rainiest years of the region), allowing for comparison with naturally watered trees. Using dynamic enclosure chambers at the branch level and PTR-MS-Q-ToF, we screened the anabolic VOC (isoprene, methanol) and the catabolic VOC (e.g. methacrolein, methyl vinyl ketone, C6 aldehydes and carboxylic acids) of trees located under the

  13. VALIDATION OF A NEW SOIL VOC SAMPLER

    Energy Technology Data Exchange (ETDEWEB)

    Susan S. Sorini; John F. Schabron

    1997-04-01

    The overall objective of this project is to facilitate national acceptance of the EnCore{trademark} sampling/storage device by conducting product tests, method development, and method validation activities. The specific goals for the initial six-month period of the project are listed: (1) Evaluate and become familiar with the stainless steel EnCore{trademark} sampling/storage device for collecting and holding soil samples for determination of volatile organic compounds (VOCs); (2) Initiate interaction with American Society for Testing and Materials (ASTM) Committee D-34 on Waste Management to begin the ASTM standard preparation and approval process; (3) Prepare an ASTM drall practice for using a device fitting the description of the EnCore{trademark} sampler for sampling and storing soil for volatile organic analysis. Under ASTM guidelines, the procedure describing the use of a device, such as the EnCore{trademark} sampler, is referred to as a practice rather than a method because it is a definitive set of instructions for performing one or more specific operations that does not produce a test result (ASTM 1996a); and (4) Plan testing needed to establish maximum storage temperatures and times for inclusion in the ASTM practice.

  14. ASSESSMENT OF VOC EMISSIONS FROM FIBERGLASS BOAT MANUFACTURING

    Science.gov (United States)

    The report presents an assessment of volatile organic compound (VOC) emissions from fiberglass boat manufacturing. Description of the industry structure is presented, including estimates of the number of facilities, their size, and geographic distribution. The fiberglass boat m...

  15. 40 CFR Table 1 to Subpart C - VOC Content Limits by Product Category

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false VOC Content Limits by Product Category..., Table 1 Table 1 to Subpart C—VOC Content Limits by Product Category Product category VOC content limit (weight-percent VOC) Air fresheners: Single-phase 70 Double-phase 30 Liquids/pump sprays 18 Solids/gels 3...

  16. Zero VOC, Coal Tar Free Splash Zone Coating (SZC)

    Science.gov (United States)

    2011-09-01

    volatile organic compounds (VOC) content, hazardous air pollutants (HAP), and may also include hazardous pigment content. The coal tar epoxy also...VOCs, HAPs of methyl isobutyl ketone (MIBK) and xylene, and the pigment chromium oxide. Each coat of SSPC PS 11.01 contains 30% by weight coal tar...marketed a millable gum polysulfide known as the first synthetic rubber commercially made in the United States. Today, there are several liquid

  17. Exposure to genotoxic compounds alters in vitro cellular VOC excretion.

    Science.gov (United States)

    Fijten, Rianne; Smolinska, Agnieszka; Shi, Quan; Pachen, Daniëlle; Dallinga, Jan; Boots, Agnes; van Schooten, Frederik Jan

    2017-10-03

    Genotoxic carcinogens significantly damage cells and tissues by targeting macromolecules such as proteins and DNA, but their mechanisms of action and effects on human health are diverse. Consequently, determining the amount of exposure to a carcinogen and its cellular effects is essential, yet difficult. The aim of this manuscript was to investigate the potential of detecting alterations in Volatile Organic Compounds (VOCs) profiles in the in vitro headspace of pulmonary cells after exposure to the genotoxic carcinogens cisplatin and benzo[a]pyrene using two different sampling set-ups. A prototype set-up was used for the cisplatin exposure, whereas a modified set-up was utilized for the benzo[a]pyrene exposure. Both carcinogens were added to the cell medium for 24 hours. The headspace in the culture flask was sampled to measure the VOC content using gas chromatography - time of flight - mass spectrometry. Eight cisplatin-specific VOCs and six benzo[a]pyrene-specific VOCs were discriminatory between treated and non-treated cells. Since the in vivo biological effects of both genotoxic compounds are well-defined, the origin of the identified VOCs could potentially be traced back to common cellular processes including cell cycle pathways, DNA damage and repair. These results indicate that exposing lung cells to genotoxins alters headspace VOC profiles, suggesting that it might be possible to monitor VOC changes in vivo to study drug efficacy or exposure to different pollutants. In conclusion, this study emphasizes the innovative potential of in vitro VOCs experiments to determine their in vivo applicability and discover their endogenous origin. . © 2017 IOP Publishing Ltd.

  18. Diffusion-controlled toluene reference material for VOC emissions testing: international interlaboratory study.

    Science.gov (United States)

    Howard-Reed, Cynthia; Liu, Zhe; Cox, Steven; Leber, Dennis; Samarov, Dan; Little, John C

    2014-04-01

    The measurement of volatile organic compound (VOC) emissions from building products and materials by manufacturers and testing laboratories, and the use of the test results for labeling programs, continue to expand. One issue that hinders wide acceptance for chamber product testing is the lack of a reference material to validate test chamber performance. To meet this need, the National Institute of Standards and Technology (NIST) and Virginia Tech (VT) have developed a prototype reference material that emits a single VOC similar to the emissions of a diffusion-controlled building product source with a dynamic emissions profile. The prototype material has undergone extensive testing at NIST and a pilot interlaboratory study (ILS) with four laboratories. The next development step is an evaluation of the prototype source in multiple-sized chambers of 14 laboratories in seven countries. Each laboratory was provided duplicate specimens and a test protocol. Study results identified significant issues related to the need to store the source at a subzero Celsius temperature until tested and possible inconsistencies in large chambers. For laboratories using a small chamber and meeting all the test method criteria, the results were very encouraging with relative standard deviations ranging from 5% to 10% across the laboratories. Currently, the chamber performance of laboratories conducting product VOC emissions testing is assessed through interlaboratory studies (ILS) using a source with an unknown emission rate. As a result, laboratory proficiency can only be based on the mean and standard deviation of emission rates measured by the participating ILS laboratories. A reference material with a known emission rate has the potential to provide an independent assessment of laboratory performance as well as improve the quality of interlaboratory studies. Several international laboratories with different chamber testing systems demonstrated the ability to measure the emission rate

  19. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  20. Hydrogen sulphide, odor, and VOC air emission control systems for heavy oil storage, transport, and processing operations

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, H.P. [APC Technologies, Inc. (Canada)

    2011-07-01

    In the heavy oil industry, companies have to control their air emissions in compliance with regulatory and process improvement objectives. The industry therefore operates air emission control systems to eliminate odor complaints, reduce personnel exposure to H2S and remove BTEX and VOC emissions. This paper studies different cases of companies which have chosen to use a fixed activated carbon adsorption unit. The study was conducted on three cases of heavy oil industries which installed the CarbonPure adsorption system and describes their objectives, processes, emissions, technology options and performances. Results showed an elimination of odor complaints, a reduction of personnel exposure to harmful air contaminants and a reduction of VOC concentrations in a reliable, low maintenance and economic manner. This study presents the greater benefits of the CarbonPure adsorption system combined with an ultra high efficiency unit over those of other adsorption systems.

  1. A WRF-Chem model study of the impact of VOCs emission of a huge petro-chemical industrial zone on the summertime ozone in Beijing, China

    Science.gov (United States)

    Wei, Wei; Lv, Zhao Feng; Li, Yue; Wang, Li Tao; Cheng, Shuiyuan; Liu, Huan

    2018-02-01

    In China, petro-chemical manufacturing plants generally gather in the particular industrial zone defined as PIZ in some cities, and distinctly influence the air quality of these cities for their massive VOCs emissions. This study aims to quantify the local and regional impacts of PIZ VOCs emission and its relevant reduction policy on the surface ozone based on WRF-Chem model, through the case study of Beijing. Firstly, the model simulation under the actual precursors' emissions over Beijing region for July 2010 is conducted and evaluated, which meteorological and chemical predictions both within the thresholds for satisfactory model performance. Then, according to simulated H2O2/HNO3 ratio, the nature of photochemical ozone formation over Beijing is decided, the VOCs-sensitive regime over the urban areas, NOx-sensitive regime over the northern and western rural areas, and both VOCssbnd and NOx-mixed sensitive regime over the southern and eastern rural areas. Finally, a 30% VOCs reduction scenario (RS) and a 100% VOCs reduction scenario (ZS) for Beijing PIZ are additional simulated by WRF-Chem. The sensitivity simulations imply that the current 30% reduction policy would bring about an O3 increase in the southern and western areas (by +4.7 ppb at PIZ site and +2.1 ppb at LLH station), and an O3 decrease in the urban center (by -1.7 ppb at GY station and -2.5 ppb at DS station) and in the northern and eastern areas (by -1.2 ppb at MYX station), mainly through interfering with the circulation of atmospheric HOx radicals. While the contribution of the total VOCs emission of PIZ to ozone is greatly prominent in the PIZ and its surrounding areas along south-north direction (12.7% at PIZ site on average), but slight in the other areas of Beijing (<3% in other four stations on average).

  2. Sources

    OpenAIRE

    2015-01-01

    Sources Fondation Pablo Iglesias. Alcala de Henares. Sections : Archives privées de Manuel ArijaArchives extérieuresArchives FNJS de EspañaPrensa Archives Générales de l’Administration. Alcala de Henares. Sections : Opposition au franquismeSig. 653 Sig TOP 82/68.103-68.602.Índice de las cartas colectivas, Relaciones, Cartas al Ministro de Información de Marzo de 1965. c.662. Sources cinématographiques Filmothèque Nationale d’Espagne.NO.DO. N° 1157C. 08/03/1965.aguirre Javier, Blanco vertical....

  3. Factorization methods applied to characterize the sources of volatile organic compounds in Montreal, Quebec

    Directory of Open Access Journals (Sweden)

    Eugeniusz Porada

    2016-02-01

    Full Text Available Objectives: The study objective was to assemble emission characteristics of the sources of the ambient volatile organic compounds (VOCs and to elaborate methods of organizing them into the sources’ chemical profiles. Material and Methods: The UNMIX – sensor modeling method from the U.S. Environment Protection Agency (EPA – was used to process the VOC concentration data acquired over the years 2000–2009 for 175 VOC species in 4 air quality monitoring stations in Montreal, Quebec. Results: The method enabled to assess VOC emissions from the typically distributed sources existing in urban environment and VOC occurrences characterizing the local, or point-like, sources. The distributed sources were inextricably associated with hydrocarbons from exhaust, heavier hydrocarbons from contaminated urban soil, fugitive evaporations of gasoline and liquefied petroleum gases (LPG, leakage from the industrial and commercial use of solvents, and the inert, ozone depleting gases permeating urban atmosphere. The sources’ profiles were charted involving 60–120 VOC species per source. Spatial distribution of the sources was examined. Conclusions: The UNMIX application and the source profiling methods, by building robust chemical profiles of VOC sources, provided information that can be used to assign the measured VOC emissions to physical sources. This, in turn, provides means of assessing the impact of environmental policies, on one hand, and of industrial activities on the other hand on VOC air pollution.

  4. Fabrication of Functional Polyurethane/Rare Earth Nanocomposite Membranes by Electrospinning and Its VOCs Absorption Capacity from Air

    Directory of Open Access Journals (Sweden)

    Jun Cong Ge

    2017-03-01

    Full Text Available Volatile organic compounds (VOCs are a source of air pollution and are harmful to both human health and the environment. In this study, we fabricated polyurethane/rare earth (PU/RE composite nanofibrous membranes via electrospinning with the aim of removing VOCs from air. The morphological structure of PU/RE nanofibrous mats was investigated using field emission scanning electron microscopy (FE-SEM, fourier transform infrared spectroscopy (FTIR, and X-ray diffraction (XRD experimental analyses. A certain amount of RE (up to 50 wt. % compared to PU pellets nanoparticles (NPs could be loaded on/into PU fibers. The tensile strength of PU/RE nanofibrous membranes decreased slightly with the increasing RE powder content. The PU nanofiber containing 50 wt. % RE powder had the smallest fiber diameter of 356 nm; it also showed the highest VOC absorption capacity compared with other composite membranes, having an absorption capacity about three times greater than pure PU nanofibers. In addition, all of the PU/RE nanofibrous membranes readily absorbed styrene the most, followed by xylene, toluene, benzene and chloroform. Therefore, the PU/RE nanofibrous membrane can play an important role in removing VOCs from the air, and its development prospects are impressive because they are emerging materials.

  5. The European wool-carder bee (Anthidium manicatum) eavesdrops on plant volatile organic compounds (VOCs) during trichome collection.

    Science.gov (United States)

    Graham, Kelsey K; Brown, Steve; Clarke, Stephanie; Röse, Ursula S R; Starks, Philip T

    2017-11-01

    The plant-pollinator relationship is generally considered mutualistic. This relationship is less clear, however, when pollinators also cause tissue damage. Some Megachilidae bees collect plant material for nests from the plants they pollinate. In this study, we examined the relationship between Anthidium manicatum, the European wool-carder bee, and the source of its preferred nesting material - Stachys byzantina, lamb's ear. Female A. manicatum use their mandibles to trim trichomes from plants for nesting material (a behaviour dubbed "carding"). Using volatile organic compound (VOC) headspace analysis and behavioural observations, we explored (a) how carding effects S. byzantina and (b) how A. manicatum may choose specific S. byzantina plants. We found that removal of trichomes leads to a dissimilar VOC bouquet compared to intact leaves, with a significant increase in VOC detection following damage. A. manicatum also visit S. byzantina plants with trichomes removed at a greater frequency compared to plants with trichomes intact. Our data suggest that A. manicatum eavesdrop on VOCs produced by damaged plants, leading to more carding damage for individual plants due to increased detectability by A. manicatum. Accordingly, visitation by A. manicatum to S. byzantina may incur both a benefit (pollination) and cost (tissue damage) to the plant. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. TO PURGE OR NOT TO PURGE? VOC CONCENTRATION ...

    Science.gov (United States)

    Soil vapor surveys are commonly used as a screening technique to delineate volatile organic compound (VOC) contaminant plumes and provide information for soil sampling plans. Traditionally, three purge volumes of vapor are removed before a sample is collected. One facet of this study was to evaluate the VOC concentrations lost during purging and explore the potential implications of those losses. The vapor data was compared to collocated soil data to determine if any correlation existed between the VOC concentrations. Two different methods for soil vapor collection were compared: 1) active/micro-volume; and 2) active/macro-volume. The active/micro-volume vapor sample had total line purge volume of 1.25 mL and the active/macro-volume vapor sample had a total line purge volume of 15 mL. Six line purge volumes were collected for each vapor sampling technique, with the fourth purge volume representing the traditional sample used for site screening data. Each sample was collected by gas tight syringe and transferred to a thermal de sorption tube for sorption, transport, and analysis. Following the removal of the soil vapor samples, collocated soil samples were taken. For both active vapor sampling techniques, the VOC concentrations in the first three purge volumes exceeded the VOC concentrations in the last three purge volumes. This implies that the general rule of removal of three purge volumes prior to taking a sample for analysis could lead to underestimating the

  7. Novel collection method for volatile organic compounds (VOCs) from dogs.

    Science.gov (United States)

    Holderman, Chris J; Kaufman, Phillip E; Booth, Matthew M; Bernier, Ulrich R

    2017-09-01

    Host derived chemical cues are an important aspect of arthropod attraction to potential hosts. Host cues that act over longer distances include CO2, heat, and water vapor, while cues such as volatile organic compounds (VOCs) act over closer distances. Domestic dogs are important hosts for disease cycles that include dog heartworm disease vectored by mosquitoes, however the host VOCs utilized by vectors are not well known. Herein we present a novel method that sampled VOCs from a dog host. A Tenax TD stainless steel tube was held near a dog's fur and skin, which collected VOCs that were later desorbed and tentatively identified using a gas chromatograph-mass spectrospectrometer (GC-MS). Background air chemicals were subtracted from the dog sample, resulting in 182 differentiated compounds, a majority of which were identified by ionization fragmentation patterns. Four dogs were sampled and shared 41 of the identified chemicals. VOCs were representative of aliphatics, aromatics, aldehydes, alcohols and carboxylic acids. This chemical characterization method has the potential to identify both individuals and breeds of dogs in addition to other potential uses such as disease diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Modelling study of boundary-layer ozone over northern China - Part II: Responses to emission reductions during the Beijing Olympics

    Science.gov (United States)

    Tang, Guiqian; Zhu, Xiaowan; Xin, Jinyuan; Hu, Bo; Song, Tao; Sun, Yang; Wang, Lili; Wu, Fangkun; Sun, Jie; Cheng, Mengtian; Chao, Na; Li, Xin; Wang, Yuesi

    2017-09-01

    The implementation of emission reduction measures during the Olympics provided a valuable opportunity to study regional photochemical pollution over northern China. In this study, the fifth-generation Pennsylvania State University/National Centre for Atmospheric Research Mesoscale Model and Community Multiscale Air Quality model system was applied to conduct two sets of modelling analyses of the period from July 20 to September 20, 2008, to illustrate the influences of emission reduction measures on regional photochemical pollution over northern China during the Beijing Olympics. The results indicated that the implementation of emission control measures decreased the concentrations of ozone (O3) precursors, namely nitrogen oxide (NOx) and volatile organic compounds (VOCs), throughout the boundary layer. The concentrations of these compounds were reduced by 45% in the central urban area of Beijing at the ground level. Although the average O3 concentration in the central urban area increased by more than 8 ppbv, the total oxidant concentration decreased significantly by more than 5 ppbv. Greater O3 concentrations mainly occurred during periods with weak photochemical reactions. During periods of strong photochemical production, the O3 concentration decreased significantly due to a weakening vertical circulation between the lower and upper boundary layer. Consequently, the number of days when the O3 concentration exceeded 100 ppbv decreased by 25% in Beijing. The emission control measures altered the sensitivity of the regional O3 production. The coordinated control region of NOx and VOCs expanded, and the control region of VOCs decreased in size. The reduction of non-point-source emissions, such as fugitive VOCs and vehicles, was more useful for controlling regional photochemical pollution over northern China.

  9. Forecasting of VOC emissions from traffic and industry using classification and regression multivariate methods.

    Science.gov (United States)

    Stojić, Andreja; Maletić, Dimitrije; Stanišić Stojić, Svetlana; Mijić, Zoran; Šoštarić, Andrej

    2015-07-15

    In this study, advanced multivariate methods were applied for VOC source apportionment and subsequent short-term forecast of industrial- and vehicle exhaust-related contributions in Belgrade urban area (Serbia). The VOC concentrations were measured using PTR-MS, together with inorganic gaseous pollutants (NOx, NO, NO2, SO2, and CO), PM10, and meteorological parameters. US EPA Positive Matrix Factorization and Unmix receptor models were applied to the obtained dataset both resolving six source profiles. For the purpose of forecasting industrial- and vehicle exhaust-related source contributions, different multivariate methods were employed in two separate cases, relying on meteorological data, and on meteorological data and concentrations of inorganic gaseous pollutants, respectively. The results indicate that Boosted Decision Trees and Multi-Layer Perceptrons were the best performing methods. According to the results, forecasting accuracy was high (lowest relative error of only 6%), in particular when the forecast was based on both meteorological parameters and concentrations of inorganic gaseous pollutants. Copyright © 2015. Published by Elsevier B.V.

  10. Occurrence of Indoor VOCs in Nursery School - Case Study

    Science.gov (United States)

    Juhasova Senitkova, Ingrid

    2017-10-01

    Children’s exposure to air pollutants is an important public health challenge. Particular attention should be paid to preschools because younger children are more vulnerable to air pollution than higher grade children and spend more time indoors. The concentrations of volatile organic compounds (VOCs) as well as carbon dioxide (CO2) concentrations in younger and older children’s classrooms during the winter season were studied. An electronic nose based on gas chromatography was used for the analysis of individual VOCs and a photoionization detector with a UV lamp was used for the determination of total volatile organic compounds (TVOC) concentration. Continuous measurements of CO2 concentrations both inside classrooms and outside each building were performed using automatic portable monitors. Improving ventilation, decreasing the occupancy per room and completing cleaning activities following occupancy periods can contribute to alleviating high CO2 and VOCs occurrence levels.

  11. VOC Signatures at Selected Urban Sites in Mexico City during the MCMA 2002 and 2003 Field Campaigns

    Science.gov (United States)

    Velasco, E.; Lamb, B.; Allwine, E.; Pressley, S.; Westberg, H.

    2004-12-01

    During the MCMA 2002 and 2003 field campaigns, ambient VOC concentrations were measured using automated canister sampling methods at several urban sites within Mexico City. These data, along with previously reported measurements, are examined in terms of the similarities and differences that exist for locations near the urban core, in heavily industrial areas, and at downwind urban receptor sites. Data are also compared to similar measurements for US cities. The use of ratios of compounds at different locations is valuable for highlighting the effects of dilution versus chemical aging during transport from sources to receptors. These ratios can also be used to demonstrate the effects of local industrial sources on the VOC distribution at selected locations.

  12. Quantification of industrial VOC emissions in China using Solar Occultation Flux (SOF)

    Science.gov (United States)

    Johansson, John; Mellqvist, Johan; Lingbo, Li

    2017-04-01

    As a part of a comprehensive measurement campaign in Beijing during the spring 2016, a two week study to quantify industrial VOC emissions from industrial sources using the Solar Occultation Flux (SOF) method was undertaken in Tianjin. Located approximately 100 km east of Beijing, Tianjin is the largest port in northern China and the largest hub of oil and petrochemical industries in the area. The aim of the study was to investigate how well industrial VOC emissions are accounted for in emission inventories, and the importance of these emissions for the formation of photochemical smog and secondary aerosols. The SOF method is based on absorption spectroscopy of direct infrared sunlight, which is performed from a measurement van, while driving through emission plumes containing the species of interest. Using the measured gas columns in the plume, GPS information of the movement of the van and wind measurements, the total flux of the species can be calculated. The method has previously been used to quantify VOC emissions from a large number of oil refineries and petrochemical industries in Europe, North America and the Middle East. Preliminary emission rates of alkanes as well as number of alkenes, such as ethene, propene, 1,3-butadiene and vinyl chloride has been compiled for most of the largest industrial sources in the Tianjin area. These emissions have been incorporated into a Lagrangian atmospheric chemistry model along simulated trajectories passing Tianjin on their way to Beijing. This has yielded some preliminary results for the total impact of these emissions on photochemical smog in the area.

  13. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Bjerg, Poul Løgstrup

    2012-01-01

    The impact of source mass depletion on the down-gradient contaminant mass discharge was monitored for a 19-month period as a part of a field demonstration of the ZVI-Clay soil mixing remediation technology. Groundwater samples were collected from conventional monitoring wells (120 samples...... properties in the source zone after soil mixing. The subsequent phases depended on the changed accessibility of the contaminant mass after mixing, the rate of source depletion, and the concentration gradient at the boundaries of the mixed source zone. Overall, ZVI-Clay soil mixing resulted in a significant...

  14. Modeled and observed ozone sensitivity to mobile-source emissions in Mexico City

    Directory of Open Access Journals (Sweden)

    M. Zavala

    2009-01-01

    NOx emission reductions and decrease linearly with VOC emission reductions only up to 30% from the base case. We further performed emissions perturbations from the gasoline fleet, diesel fleet, all mobile (gasoline plus diesel and all emission sources (anthropogenic plus biogenic. The results suggest that although large ozone reductions obtained in the past were from changes in emissions from gasoline vehicles, currently significant benefits could be achieved with additional emission control policies directed to regulation of VOC emissions from diesel and area sources that are high emitters of alkenes, aromatics and aldehydes.

  15. Direct measurement of VOC diffusivities in tree tissues

    DEFF Research Database (Denmark)

    Baduru, K.K.; Trapp, Stefan; Burken, Joel G.

    2008-01-01

    fundamental terminal fate processes for VOCs that have been translocated from contaminated soil or groundwater, and diffusion constitutes the mass transfer mechanism to the plant−atmosphere interface. Therefore, VOC diffusion through woody plant tissues, that is, xylem, has a direct impact on contaminant fate......, and tetrachloroethane and aromatic hydrocarbons such as benzene, toluene, and methyl tert-butyl ether. All compounds tested are currently being treated at full scale with tree-based phytoremediation. Diffusivities were determined by modeling the diffusive transport data with a one-dimensional diffusive flux model...

  16. Volatile organic compound (VOC) emissions during malting and beer manufacture

    Science.gov (United States)

    Gibson, Nigel B.; Costigan, Gavin T.; Swannell, Richard P. J.; Woodfield, Michael J.

    Estimates have been made of the amounts of volatile organic compounds (VOCs) released during different stages of beer manufacture. The estimates are based on recent measurements and plant specification data supplied by manufacturers. Data were obtained for three main manufacturing processes (malting, wort processing and fermentation) for three commercial beer types. Some data on the speciation of emitted compounds have been obtained. Based on these measurements, an estimate of the total unabated VOC emission. from the U.K. brewing industry was calculated as 3.5 kta -1, over 95% of which was generated during barley malting. This value does not include any correction for air pollution control.

  17. Bubble-facilitated VOC transport from LNAPL smear zones and its potential effect on vapor intrusion: Laboratory experiments

    Science.gov (United States)

    Soucy, N. C.; Mumford, K. G.

    2016-12-01

    Light non-aqueous phase liquid (LNAPL) sources can pose a significant threat to indoor air through the volatilization of hydrocarbons from the source and the subsequent transport of vapor through the soil. If subjected to the rise and fall of a water table, an LNAPL source can become a smear zone that consists of trapped discontinuous LNAPL blobs (residual) and has a higher aqueous permeability and higher surface area-to-volume ratio than pool sources. The rise and fall of a water table can also trap atmospheric air bubbles alongside the LNAPL. If these bubbles expand and become mobile, either through partitioning of volatile organic compounds (VOCs) or the production of biogenic gases, bubble-facilitated vertical vapor transport can occur. It is important to understand the bubble-facilitated transport of VOCs as it is a mechanism that could lead to faster transport. The transport of VOCs from smear zones was investigated using laboratory column and visualization experiments. In the column experiments, pentane LNAPL was emplaced in a 5 cm sand-packed source zone and the water level was raised and lowered to trap residual LNAPL and air bubbles. Each column also contained a 10 cm-high zone of clean saturated sand, and a 10 cm vadose zone of 4 mm-diameter glass beads. Water was pumped through the source and occlusion zones, and air flowed across the top of the column, where vapor samples were collected and analyzed immediately by gas chromatography. In the visualization experiments, pentane LNAPL was emplaced in a two-dimensional cell designed to allow visualization of mobilized LNAPL and gas through glass walls. Results of the column experiments showed VOC mass fluxes in test columns were 1-2 orders of magnitude greater than in the control columns. In addition, the flux signal was intermittent, consistent with expectations of bubble-facilitated transport. The results from the visualization experiments showed gas fingers growing and mobilizing over time, and supports

  18. Sources

    OpenAIRE

    2014-01-01

    Archives Archivo Histórico del Estado de Jalisco Fondo Gobernación, Asunto Pasaportes y Salvoconductos : G-8-877/9773-9775 G-8-878/9774, 9776, 9777 et 9781 G-8-879/9782-9788 G-8-880/9789-9798 G-8-881-882/9803 G-8-882/9804-9805 G-8-883/9806-9811 G-8-884/9813 G-8-885/9817-9820 G-8-886/9822-9825 G-8-887/9826-9830 G-8-888/9835 G-8-889-890/9837 G-8-889/9839 Sources imprimées Livres et chroniques O’Farrill Romulo, (2004) Reseña histórica estadística y comercial de México y sus estados, directorio g...

  19. Photo-illuminated diamond as a solid-state source of solvated electrons in water for nitrogen reduction.

    Science.gov (United States)

    Zhu, Di; Zhang, Linghong; Ruther, Rose E; Hamers, Robert J

    2013-09-01

    The photocatalytic reduction of N₂ to NH₃ is typically hampered by poor binding of N₂ to catalytic materials and by the very high energy of the intermediates involved in this reaction. Solvated electrons directly introduced into the reactant solution can provide an alternative pathway to overcome such limitations. Here we demonstrate that illuminated hydrogen-terminated diamond yields facile electron emission into water, thus inducing reduction of N₂ to NH₃ at ambient temperature and pressure. Transient absorption measurements at 632 nm reveal the presence of solvated electrons adjacent to the diamond after photoexcitation. Experiments using inexpensive synthetic diamond samples and diamond powder show that photocatalytic activity is strongly dependent on the surface termination and correlates with the production of solvated electrons. The use of diamond to eject electrons into a reactant liquid represents a new paradigm for photocatalytic reduction, bringing electrons directly to reactants without requiring molecular adsorption to the surface.

  20. CH4 production via CO2 reduction in a temperate bog - A source of (C-13)-depleted CH4

    Science.gov (United States)

    Lansdown, J. M.; Quay, P. D.; King, S. L.

    1992-01-01

    The paper reports measurements, taken over two annual cycles, of the flux and delta(C-13) of CH4 released from an acidic peat bog located in the foothills of the Cascade Range in Washington state, U.S. Measurements of the rate of aceticlastic methanogenesis and CO2 reduction in peat soil, using (C-14)-labeled acetate and sodium bicarbonate, show that acetate was not an important CH4 precursor and that CO2 reduction could account for all of the CH4 production. The in situ kinetic isotope effect for CO2 reduction, calculated using the delta-(C-13) of soil water CO2 and CH4 flux, was 0.932 +/- 0.007.

  1. Regio- and chemoselective reduction of nitroarenes and carbonyl compounds over recyclable magnetic ferrite-nickel nanoparticles (Fe(3)O(4)-Ni) by using glycerol as a hydrogen source.

    Science.gov (United States)

    Gawande, Manoj B; Rathi, Anuj K; Branco, Paula S; Nogueira, Isabel D; Velhinho, Alexandre; Shrikhande, Janhavi J; Indulkar, Utkarsha U; Jayaram, Radha V; Ghumman, C Amjad A; Bundaleski, Nenad; Teodoro, Orlando M N D

    2012-10-01

    Reduction by magnetic nano-Fe(3)O(4)-Ni: a facile, simple and environmentally friendly hydrogen-transfer reaction that takes place over recyclable ferrite-nickel magnetic nanoparticles (Fe(3)O(4)-Ni) by using glycerol as hydrogen source allows aromatic amines and alcohols to be synthesized from the precursor nitroarenes and carbonyl compounds. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Source zone remediation by ZVI-clay soil-mixing: Reduction of tetrachloroethene mass and mass discharge at a Danish DNAPL site

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Binning, Philip John

    2012-01-01

    The presence of chlorinated solvent source zones in the subsurface pose a continuous threat to groundwater quality. The remediation of Dense Non-Aqueous Phase Liquid (DNAPL) sites is especially challenging and the development of innovative remediation technologies is needed. Zero-valent iron (ZVI...... the chlorinated ethenes was limited to 21 %. Long-term modeling (Comsol Multiphysics) was used to predict that a contaminant mass discharge reduction of 2-3 orders in magnitude will take 3-5 years....

  3. Measurements and modeling to quantify emissions of methane and VOCs from shale gas operations: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Presto, Albert A [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-06-30

    The objectives of the project were to determine the leakage rates of methane and ozone-forming Volatile Organic Compounds (VOCs) and the emission rates of air toxics from Marcellus shale gas activities. Methane emissions in the Marcellus Shale region were differentiated between “newer” sources associated with shale gas development and “older” sources associated with coal or conventional natural gas exploration. This project conducted measurements of methane and VOC emissions from both shale and non-shale natural gas resources. The initial scope of the project was the Marcellus Shale basin, and measurements were conducted in both the western wet gas regions (southwest PA and WV) and eastern dry gas region (northeast PA) of the basin. During this project, we obtained additional funding from other agencies to expand the scope of measurements to include additional basins. The data from both the Marcellus and other basins were combined to construct a national analysis of methane emissions from oil & gas production activities.

  4. Solid-Phase Microextraction and the Human Fecal VOC Metabolome

    Science.gov (United States)

    Dixon, Emma; Clubb, Cynthia; Pittman, Sara; Ammann, Larry; Rasheed, Zeehasham; Kazmi, Nazia; Keshavarzian, Ali; Gillevet, Pat; Rangwala, Huzefa; Couch, Robin D.

    2011-01-01

    The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein. PMID:21494609

  5. Novel collection method for volatile organic compounds (VOCs) from dogs

    Science.gov (United States)

    Host derived chemical cues are an important aspect of arthropod attraction to potential hosts. Host cues that act over longer distances include CO2, heat, and water vapor, while cues such as volatile organic compounds (VOCs) act over closer distances. Domestic dogs are important hosts for disease cy...

  6. [Emission Characteristics of VOCs from Typical Restaurants in Beijing].

    Science.gov (United States)

    Cui, Tong; Cheng, Jing-chen; He, Wan-qing; Ren, Pei-fang; Nie, Lei; Xu, Dong-yao; Pan, Tao

    2015-05-01

    Using the EPA method, emission of volatile organic compounds (VOCs) , sampled from barbecue, Chinese and Western fast-food, Sichuan cuisine and Zhejiang cuisine restaurants in Beijing was investigated. VOCs concentrations and components from different cuisines were studied. The results indicated that based on the calibrated baseline ventilation volume, the VOCs emission level from barbecue was the highest, reaching 12.22 mg · m(-3), while those from fast-food of either Chinese or Western, Sichuan cuisine and Zhejiang cuisine were about 4 mg · m(-3). The components of VOCs from barbecue were different from those in the other cuisines, which were mainly propylene, 1-butene, n-butane, etc. The non-barbecue cuisines consisted of high concentration of alcohols, and Western fast-food contained relatively high proportion of aldehydes and ketones organic compounds. According to emission concentration of baseline ventilation volume, barbecue released more pollutants than the non-barbecue cuisines at the same scale. So, barbecue should be supervised and controlled with the top priority.

  7. CASE STUDIES: LOW-VOC/HAP WOOD FURNITURE COATINGS

    Science.gov (United States)

    The report gives results of a study in which wood furniture manufacturing facilities were identified that had converted at least one of their primary coating steps to low-volatile organic compound (VOC)/hazardous Air pollutant (HAP) wood furniture coatings: high-solids, water...

  8. Solid-phase microextraction and the human fecal VOC metabolome.

    Directory of Open Access Journals (Sweden)

    Emma Dixon

    Full Text Available The diagnostic potential and health implications of volatile organic compounds (VOCs present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.

  9. Accuracy of seven vapour intrusion algorithms for VOC in groundwater

    NARCIS (Netherlands)

    Provoost, J.; Reijnders, L.; Swartjes, F.; Bronders, J.; Seuntjens, P.; Lijzen, J.

    2009-01-01

    Background, aim and scope: During the last decade, soil contamination with volatile organic contaminants (VOC) received special attention because of their potential to cause indoor air problems. Moreover, research has shown that people spend 64% to 94% of there time indoors; therefore, the indoor

  10. EVALUATION OF SINK EFFECTS ON VOCS FROM A LATEX PAINT

    Science.gov (United States)

    The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and texanol. These oxygenated compounds rep...

  11. Emissions of Volatile Organic Compounds (VOCs) Associated with Natural Gas Production in the Uintah Basin, Utah

    Science.gov (United States)

    Warneke, C.; Geiger, F.; Zahn, A.; Graus, M.; De Gouw, J. A.; Gilman, J. B.; Lerner, B. M.; Roberts, J. M.; Edwards, P. M.; Dube, W. P.; Brown, S. S.; Peischl, J.; Ryerson, T. B.; Williams, E. J.; Petron, G.; Kofler, J.; Sweeney, C.; Karion, A.; Dlugokencky, E. J.

    2012-12-01

    Technological advances such as hydraulic fracturing have led to a rapid increase in the production of natural gas from several basins in the Rocky Mountain West, including the Denver-Julesburg basin in Colorado, the Uintah basin in Utah and the Upper Green River basin in Wyoming. There are significant concerns about the impact of natural gas production on the atmosphere, including (1) emissions of methane, which determine the net climate impact of this energy source, (2) emissions of reactive hydrocarbons and nitrogen oxides, and their contribution to photochemical ozone formation, and (3) emissions of air toxics with direct health effects. The Energy & Environment - Uintah Basin Wintertime Ozone Study (UBWOS) in 2012 was focused on addressing these issues. During UBWOS, measurements of volatile organic compounds (VOCs) were made using proton-transfer-reaction mass spectrometry (PTR-MS) instruments from a ground site and a mobile laboratory. Measurements at the ground site showed mixing ratios of VOCs related to oil and gas extraction were greatly enhanced in the Uintah basin, including several days long periods of elevated mixing ratios and concentrated short term plumes. Diurnal variations were observed with large mixing ratios during the night caused by low nighttime mixing heights and a shift in wind direction during the day. The mobile laboratory sampled a wide variety of individual parts of the gas production infrastructure including active gas wells and various processing plants. Included in those point sources was a new well that was sampled by the mobile laboratory 11 times within two weeks. This new well was previously hydraulically fractured and had an active flow-back pond. Very high mixing ratios of aromatics were observed close to the flow-back pond. The measurements of the mobile laboratory are used to determine the source composition of the individual point sources and those are compared to the VOC enhancement ratios observed at the ground site. The

  12. Detection and reduction of diffuse liquid and gas emissions in chemical and petrochemical industries; Ermittlung und Verminderung diffuser fluessiger und gasfoermiger Emissionen in der chemischen und petrochemischen Industrie

    Energy Technology Data Exchange (ETDEWEB)

    Koeppke, K.E. [Witten-Herdecke Univ. gGmbH, Witten (Germany). Inst. fuer Umwelttechnik und Management; Cuhls, C. [Halle-Wittenberg Univ., Halle (Germany). Inst. fuer Umwelttechnik

    2002-09-01

    In order to improve environmental protection, VOC emissions from diffuse sources are of growing importance. For the first time in Germany the present research report gives a detailed presentation of: constructive measures for the avoidance and reduction of diffuse emissions, adequate assembling procedures for equipments and installations, technical possibilities of leak detection and, different methods for the estimation of total emissions from chemical and petrochemical production plants. On the basis of own investigations and monitoring measures taken at various plants of chemical and petrochemical industries different measuring techniques for leak detection as well as methods for the estimation of total emissions from diffuse sources are analysed and their limits are described. (orig.)

  13. 40 CFR 80.71 - Descriptions of VOC-control regions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Descriptions of VOC-control regions... VOC-control regions. (a) Reformulated gasoline covered areas which are located in the following States are included in VOC-Control Region 1: Alabama Arizona Arkansas California Colorado District of...

  14. 40 CFR 60.562-2 - Standards: Equipment leaks of VOC.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Equipment leaks of VOC. 60... Volatile Organic Compound (VOC) Emissions from the Polymer Manufacturing Industry § 60.562-2 Standards: Equipment leaks of VOC. (a) Each owner or operator of an affected facility subject to the provisions of this...

  15. Seasonal variations in VOC emission rates from gorse (Ulex europaeus)

    Science.gov (United States)

    Boissard, C.; Cao, X.-L.; Juan, C.-Y.; Hewitt, C. N.; Gallagher, M.

    Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10-1300 μmol m-2 s-1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, trans-ocimene and γ-terpinene were also emitted, with α-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33-66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 μg C (g dwt)-1 h-1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 μg C (g dwt)-1 h-1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.

  16. Reduction of plasma density in the Helicity Injected Torus with Steady Inductance experiment by using a helicon pre-ionization source.

    Science.gov (United States)

    Hossack, Aaron C; Firman, Taylor; Jarboe, Thomas R; Prager, James R; Victor, Brian S; Wrobel, Jonathan S; Ziemba, Timothy

    2013-10-01

    A helicon based pre-ionization source has been developed and installed on the Helicity Injected Torus with Steady Inductance (HIT-SI) spheromak. The source initiates plasma breakdown by injecting impurity-free, unmagnetized plasma into the HIT-SI confinement volume. Typical helium spheromaks have electron density reduced from (2-3) × 10(19) m(-3) to 1 × 10(19) m(-3). Deuterium spheromak formation is possible with density as low as 2 × 10(18) m(-3). The source also enables HIT-SI to be operated with only one helicity injector at injector frequencies above 14.5 kHz. A theory explaining the physical mechanism driving the reduction of breakdown density is presented.

  17. Reduction of plasma density in the Helicity Injected Torus with Steady Inductance experiment by using a helicon pre-ionization source

    Energy Technology Data Exchange (ETDEWEB)

    Hossack, Aaron C.; Jarboe, Thomas R.; Victor, Brian S. [Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195 (United States); Firman, Taylor; Prager, James R.; Ziemba, Timothy [Eagle Harbor Technologies, Inc., 119 W. Denny Way, Suite 210, Seattle, Washington 98119 (United States); Wrobel, Jonathan S. [979B West Moorhead Circle, Boulder, Colorado 80305 (United States)

    2013-10-15

    A helicon based pre-ionization source has been developed and installed on the Helicity Injected Torus with Steady Inductance (HIT-SI) spheromak. The source initiates plasma breakdown by injecting impurity-free, unmagnetized plasma into the HIT-SI confinement volume. Typical helium spheromaks have electron density reduced from (2–3) × 10{sup 19} m{sup −3} to 1 × 10{sup 19} m{sup −3}. Deuterium spheromak formation is possible with density as low as 2 × 10{sup 18} m{sup −3}. The source also enables HIT-SI to be operated with only one helicity injector at injector frequencies above 14.5 kHz. A theory explaining the physical mechanism driving the reduction of breakdown density is presented.

  18. Ozone production and its sensitivity to NOx and VOCs: results from the DISCOVER-AQ field experiment, Houston 2013

    Directory of Open Access Journals (Sweden)

    G. M. Mazzuca

    2016-11-01

    Full Text Available An observation-constrained box model based on the Carbon Bond mechanism, version 5 (CB05, was used to study photochemical processes along the NASA P-3B flight track and spirals over eight surface sites during the September 2013 Houston, Texas deployment of the NASA Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality (DISCOVER-AQ campaign. Data from this campaign provided an opportunity to examine and improve our understanding of atmospheric photochemical oxidation processes related to the formation of secondary air pollutants such as ozone (O3. O3 production and its sensitivity to NOx and volatile organic compounds (VOCs were calculated at different locations and times of day. Ozone production efficiency (OPE, defined as the ratio of the ozone production rate to the NOx oxidation rate, was calculated using the observations and the simulation results of the box and Community Multiscale Air Quality (CMAQ models. Correlations of these results with other parameters, such as radical sources and NOx mixing ratio, were also evaluated. It was generally found that O3 production tends to be more VOC-sensitive in the morning along with high ozone production rates, suggesting that control of VOCs may be an effective way to control O3 in Houston. In the afternoon, O3 production was found to be mainly NOx-sensitive with some exceptions. O3 production near major emissions sources such as Deer Park was mostly VOC-sensitive for the entire day, other urban areas near Moody Tower and Channelview were VOC-sensitive or in the transition regime, and areas farther from downtown Houston such as Smith Point and Conroe were mostly NOx-sensitive for the entire day. It was also found that the control of NOx emissions has reduced O3 concentrations over Houston but has led to larger OPE values. The results from this work strengthen our understanding of O3 production; they indicate that controlling NOx

  19. Thomson scattering laser-electron X-ray source for reduction of patient radiation dose in interventional coronary angiography

    Science.gov (United States)

    Artyukov, I. A.; Dyachkov, N. V.; Feshchenko, R. M.; Polunina, A. V.; Popov, N. L.; Shvedunov, V. I.; Vinogradov, A. V.

    2017-05-01

    It was medical applications that stimulated F. Carrol in the early 1990s to start the research of on relativistic Thomson scattering X-ray sources, as a part of the infrastructure of the future society. The possibility to use such a source in interventional cardiology is discussed in this paper. The replacement of X-ray tube by relativistic Thomson scattering Xray source is predicted to lower the patient radiation dose by a factor of 3 while image quality remains the same. The required general characteristics of accelerator and laser units are found. They can be reached by existing technology. A semiempirical method for simulation of medical and technical parameters of interventional coronary angiography systems is suggested.

  20. Proton Transfer Reaction Time-of-Flight Mass Spectrometric (PTR-TOF-MS) determination of volatile organic compounds (VOCs) emitted from a biomass fire developed under stable nocturnal conditions

    Science.gov (United States)

    Brilli, Federico; Gioli, Beniamino; Ciccioli, Paolo; Zona, Donatella; Loreto, Francesco; Janssens, Ivan A.; Ceulemans, Reinhart

    2014-11-01

    Combustion of solid and liquid fuels is the largest source of potentially toxic volatile organic compounds (VOCs), which can strongly affect health and the physical and chemical properties of the atmosphere. Among combustion processes, biomass burning is one of the largest at global scale. We used a Proton Transfer Reaction “Time-of-Flight” Mass Spectrometer (PTR-TOF-MS), which couples high sensitivity with high mass resolution, for real-time detection of multiple VOCs emitted by burned hay and straw in a barn located near our measuring station. We detected 132 different organic ions directly attributable to VOCs emitted from the fire. Methanol, acetaldehyde, acetone, methyl vinyl ether (MVE), acetic acid and glycolaldehyde dominated the VOC mixture composition. The time-course of the 25 most abundant VOCs, representing ∼85% of the whole mixture of VOCs, was associated with that of carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) emissions. The strong linear relationship between the concentrations of pyrogenic VOC and of a reference species (i.e. CO) allowed us to compile a list of emission ratios (ERs) and emission factors (EFs), but values of ER (and EF) were overestimated due to the limited mixing of the gases under the stable (non-turbulent) nocturnal conditions. In addition to the 25 most abundant VOCs, chemical formula and concentrations of the residual, less abundant VOCs in the emitted mixture were also estimated by PTR-TOF-MS. Furthermore, the evolution of the complex combustion process was described on the basis of the diverse types of pyrogenic gases recorded.

  1. Source attribution of tropospheric ozone

    Science.gov (United States)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  2. UNMIX Methods Applied to Characterize Sources of Volatile Organic Compounds in Toronto, Ontario

    Directory of Open Access Journals (Sweden)

    Eugeniusz Porada

    2016-06-01

    Full Text Available UNMIX, a sensor modeling routine from the U.S. Environmental Protection Agency (EPA, was used to model volatile organic compound (VOC receptors in four urban sites in Toronto, Ontario. VOC ambient concentration data acquired in 2000–2009 for 175 VOC species in four air quality monitoring stations were analyzed. UNMIX, by performing multiple modeling attempts upon varying VOC menus—while rejecting the results that were not reliable—allowed for discriminating sources by their most consistent chemical characteristics. The method assessed occurrences of VOCs in sources typical of the urban environment (traffic, evaporative emissions of fuels, banks of fugitive inert gases, industrial point sources (plastic-, polymer-, and metalworking manufactures, and in secondary sources (releases from water, sediments, and contaminated urban soil. The remote sensing and robust modeling used here produces chemical profiles of putative VOC sources that, if combined with known environmental fates of VOCs, can be used to assign physical sources’ shares of VOCs emissions into the atmosphere. This in turn provides a means of assessing the impact of environmental policies on one hand, and industrial activities on the other hand, on VOC air pollution.

  3. Development of dynamic loudspeakers modified as incident pressure sources for noise reduction in a double panel structure

    NARCIS (Netherlands)

    Ho, J.; Berkhoff, Arthur P.; Crocker, Malcolm J.; Pawelczyk, Marek; Paosawatyanyong, Boonchoat

    2013-01-01

    This paper presents a modified loudspeaker source for decentralized feedback cavity control in a double panel structure to reduce the noise transmission. The double panel structure con-sists of two panels with air in between and offers the advantages of low weight, low sound transmission at high

  4. Switching Loss Reduction in the Three-Phase Quasi-Z-Source Inverters Utilizing Modified Space Vector Modulation Strategies

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Davari, Pooya; Blaabjerg, Frede

    2018-01-01

    Several single-stage topologies have been introduced since kicking off the three-phase Z-source inverter (ZSI), and among these topologies, the quasi-ZSI (qZSI) is the most common one due to its simple structure and continuous input current. Furthermore, different modulation strategies, utilizing...

  5. Enhancement of open circuit voltage in InGaAsP-inverted thin-film solar cells grown by solid-source molecular beam epitaxy

    Science.gov (United States)

    Oshima, Ryuji; Makita, Kikuo; Tayagaki, Takeshi; Sugaya, Takeyoshi

    2017-11-01

    Because InGaAsP alloys grown on InP substrates with 1.05 eV bandgap are often susceptible to compositional fluctuations owing to spinodal-like decomposition due to the miscibility gap, the corresponding open circuit voltage (VOC) for InGaAsP solar cells is typically smaller than the empirically expected value. In this study, we investigate the impact of the device structure on the VOC of In0.83Ga0.17As0.36P0.64 solar cells grown by solid-source molecular beam epitaxy. In comparison to the upright homojunction cell as a baseline, a reverse saturation current density (J0) for the upright heterojunction cell was effectively reduced from 3.2×10-4 to 1.5×10-6 mA/cm2 using the n-InP emitter with higher electron mobility, resulting in an enhancement of VOC from 0.557 to 0.568 V. Owing to the reduction of J0 to 2.8×10-7 mA/cm2, the VOC was further enhanced to 0.590 V for the inverted heterojunction cell. For the reduction of J0, a longer radiative lifetime of 20.2 ns obtained for the inverted heterojunction cell by photoluminescence decay at room temperature, presumably caused by light trapping, was responsible. Consequently, the efficiency was enhanced from 9.5% for the upright homojunction cell to 12.1% for the inverted heterojunction cell. Using the inverted InGaAsP cell, we demonstrated the mechanically stacked InGaP/GaAs//inverted-InGaAsP (// denotes the bonded interface) triple-junction solar cells with enhanced VOC of 2.64 V.

  6. High-VOC biochar-effectiveness of post-treatment measures and potential health risks related to handling and storage.

    Science.gov (United States)

    Buss, Wolfram; Mašek, Ondřej

    2016-10-01

    Biochar can contain volatile organic compounds (VOCs), formed and introduced during the pyrolysis process. In some pyrolysis units or under specific conditions during production, pyrolysis vapours can deposit on biochar in significant amounts resulting in high-VOC biochar. In this study, it was tested to which extent VOCs are released from such high-VOC biochars when openly stored, which post-treatment measures are most effective in reducing phytotoxic potential and whether the VOC emissions could exceed human health-related threshold values. It was shown that the initial VOC release of high-VOC biochars can exceed occupational exposure limit values and even after 2 months, the biochars still emitted VOCs exceeding air quality guideline values. Consequently, these specific high-VOC biochars pose health risks when handled or stored openly. Simple open-air storage turned out to be insufficient for VOC removal. Low temperature treatment, on the other hand, removed VOCs from the high-VOC biochars effectively and alleviated any human health risks and phytotoxic effects. In addition to the high-VOC biochars, a low-VOC biochar was tested which did not emit any VOCs and was even able to sorb VOCs from the VOC-rich biochar to a certain extent. Thermal treatment and blending with low-VOC biochar are methods which could be used in practise to treat high-VOC biochar, reducing VOC emissions. This study revealed significant new findings on the topic of VOCs in biochar which highlights the need to include VOCs in the list of priority contaminants in biochar.

  7. [Exposure to VOCs in furniture factories in two populations in northern Colombia].

    Science.gov (United States)

    Vargas-Ramos, Yadiris E; Marrugo-Negrete, José L

    2014-01-01

    Assess the exposure to volatile organic compounds (VOCs)in furniture handicraft factories workers in two populations of Sucre (Sincelejo and Sampués), North of Colombia.Identify possible signs and/or symptoms related to exposure to these contaminants. This was an analytical cross sectional study (2011), using a questionnaire. Study population consisted of 66 individuals, 41 exposed and 25 controls. Personal samples were collected for concentration quantifying of benzene, toluene, ethylbenzene and xylenes (both groups) and contrasting them with health effects possible attributed to these contaminants. The concentrations of benzene, toluene and m/p-xylene were higher in the exposed group (9.5 mg/m(3), 8.1 mg/m(3) and 12.1 mg/m(3))compared with the control group (0.2 mg/m(3), 0.3 mg/m(3) and 0.03 mg/m(3)). Muscular pain 82.9 % (PR=3.8; CI95%:1.2-11.8) and somnolence 65.9 % (PR=4.9; CI95%:1.7-14.7)were associated with a higher exposure.Factor such as mixtures of solvents (thinner) in the work and vehicles' traffic can contribute to these results. Several sources contribute to increases personal exposure of VOCs in furniture handicraft factories workers North of Colombia. Additionally, excessive use of these compounds may be generating adverse effects on the health of workers.

  8. Spatial and temporal trends of volatile organic compounds (VOC) in a rural area of northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Parra, M.A.; Gonzalez, L.; Elustondo, D.; Garrigo, J.; Bermejo, R.; Santamaria, J.M. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra, Irunlarrea s/n, 31080, Pamplona, Navarra (Spain)

    2006-10-15

    Ambient concentrations of volatile organic compounds (VOCs) were measured at 40 rural sampling points in Navarre (northern Spain). Air samples were collected by means of sorbent passive sampling and analyzed by thermal desorption (TD) and gas chromatography/mass-selective detector (GC/MSD). A total of 140 VOCs were identified during the study, which was carried out between May to October 2004 for a total of a 10 biweekly sampling campaigns. Concentrations of benzene, toluene, ethylbenzene, m/p-xylenes, o-xylene (BTEX) and 1,3,5-trimethylbenzene were determined in order to investigate their temporal and spatial distributions. Geostatistical analysis pointed to traffic as the main emission source of these compounds. Supporting this idea, BTEX and nitrogen oxides concentrations were found to be highly significantly correlated (r=0.495, P=0.001), whereas a strong negative correlation between BTEX and ozone was also observed (r=-0.355, P=0.025). The concentrations for the BTEX group were similar to the values that have been previously reported for other rural areas. (author)

  9. Complete Mapping of Complex Disulfide Patterns with Closely-Spaced Cysteines by In-Source Reduction and Data-Dependent Mass Spectrometry

    DEFF Research Database (Denmark)

    Cramer, Christian N; Kelstrup, Christian D; Olsen, Jesper V

    2017-01-01

    bonds are present in complicated patterns. This includes the presence of disulfide bonds in nested patterns and closely spaced cysteines. Unambiguous mapping of such disulfide bonds typically requires advanced MS approaches. In this study, we exploited in-source reduction (ISR) of disulfide bonds during...... of individual disulfide bonds could be done in species containing closely spaced disulfide bonds. The strength of this methodology was demonstrated by complete mapping of all four disulfide bonds in lysozyme and all 17 disulfide bonds in human serum albumin, including nested disulfide bonds and motifs...

  10. VOC Emissions from the Potential Biofuel Crop, Switchgrass

    Science.gov (United States)

    Graus, M.; Eller, A. S.; Fall, R.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; Qian, Y.; Sekimoto, K.; Monson, R. K.; Warneke, C.

    2010-12-01

    Volatile organic compound (VOC) emission rates during the growth and simulated harvest phases were determined for three different cultivars of switchgrass (Panicum virgatum) using laboratory chamber measurements. Switchgrass is a candidate for use in second-generation (cellulosic) ethanol production and the acerage dedicated to its growth in the USA has already increased during the past decade. We estimate that the yearly emissions from switchgrass plantations, including both the growth and harvest phases, will be on the order of 3 kg C ha-1 methanol, 1 kg C ha-1 acetaldehyde, 1 kg C ha-1 acetone, 0.9 kg C ha-1 monoterpenes, 0.5 kg C ha-1 isoprene + 1-penten-3-ol, 0.2 kg C ha-1 hexenals, and 0.1 kg C ha-1 hexenols. These emission rates are lower than those expected from Eucalyptus or Poplar plantations, which are other potential biofuel crops and have significantly higher VOC emissions.

  11. Development of new source diagnostic methods and variance reduction techniques for Monte Carlo eigenvalue problems with a focus on high dominance ratio problems

    Science.gov (United States)

    Wenner, Michael T.

    Obtaining the solution to the linear Boltzmann equation is often is often a daunting task. The time-independent form is an equation of six independent variables which cannot be solved analytically in all but some special problems. Instead, numerical approaches have been devised. This work focuses on improving Monte Carlo methods for its solution in eigenvalue form. First, a statistical method of stationarity detection called the KPSS test adapted as a Monte Carlo eigenvalue source convergence test. The KPSS test analyzes the source center of mass series which was chosen since it should be indicative of overall source behavior, and is physically easy to understand. A source center of mass plot alone serves as a good visual source convergence diagnostic. The KPSS test and three different information theoretic diagnostics were implemented into the well known KENOV.a code inside of the SCALE (version 5) code package from Oak Ridge National Laboratory and compared through analysis of a simple problem and several difficult source convergence benchmarks. Results showed that the KPSS test can add to the overall confidence by identifying more problematic simulations than without its usage. Not only this, the source center of mass information on hand visually aids in the understanding of the problem physics. The second major focus of this dissertation concerned variance reduction methodologies for Monte Carlo eigenvalue problems. The CADIS methodology, based on importance sampling, was adapted to the eigenvalue problems. It was shown that the straight adaption of importance sampling can provide a significant variance reduction in determination of keff (in cases studied up to 30%?). A modified version of this methodology was developed which utilizes independent deterministic importance simulations. In this new methodology, each particle is simulated multiple times, once to every other discretized source region utilizing the importance for that region only. Since each particle

  12. Zero VOC, Coal Tar Free Splash Zone Coating (SZC)

    Science.gov (United States)

    2010-12-01

    Operating Salt Spray (Fog) Apparatus D 476 Classification for Dry Pigmentary Titanium Dioxide Pigments D 512 Test Methods for Chloride Ion...system options include high VOC content, Hazardous Air Pollutants (HAP’s) and may also include hazardous pigment content. The coal tar epoxy also...Organic Compounds (VOC’s), Hazardous Air Pollutants (HAP’s) of Methyl Isobutyl Ketone (MIBK) and Xylene, and the pigment Chromium Oxide. Each coat of

  13. Ethnicity, housing and personal factors as determinants of VOC exposures

    Science.gov (United States)

    D'Souza, Jennifer C.; Jia, Chunrong; Mukherjee, Bhrarmar; Batterman, Stuart

    Previous studies investigating effects of personal, demographic, housing and other factors on exposures to volatile organic compounds (VOC) have focused on mean or median exposures, and generally not the high exposures that are of great interest. This paper identifies determinants of personal VOC exposures on a quantile-specific basis using a nationally representative sample. The NHANES 1999-2000 VOC dataset was merged with personal, demographic, housing, smoking and occupation variables. Bivariate analyses tested for differences in geometric means and quantiles across levels of potential exposure determinants. Multivariate sample-weighted ordinary least-squares (OLS) and quantile regression (QR) models were then used to adjust for covariates. We identify a number of exposure determinants, most of which varied by exposure quantile. The most striking finding was the much higher exposures experienced by Hispanics and Blacks for aromatic VOCs (BTEX: benzene, toluene, ethylbenzene and xylenes), methyl tert-butyl ether (MTBE), and 1,4-dichlorobenzene (DCB). Exposure to gasoline, paints or glues, and having a machine-related occupation also were associated with extremely high BTEX and MTBE exposures. Additional determinants included the presence of attached garages and open windows, which affected exposures of BTEX (especially at lower quantiles) and MTBE (especially at higher quantiles). Smoking also increased BTEX exposures. DCB was associated with air freshener use, and PERC with dry-cleaned clothing. After adjusting for demographic, personal and housing factors, age and gender were not significant predictors of exposure. The use of QR in conjunction with OLS yields a more complete picture of exposure determinants, and identifies subpopulations and heterogeneous exposure groups in which some individuals experience very elevated exposures and which are not well represented by changes in the mean. The high exposures of Hispanics and Blacks are perplexing and disturbing

  14. 40 CFR Table 1 to Subpart B of... - Volatile Organic Compound (VOC) Content Limits for Automobile Refinish Coatings

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Volatile Organic Compound (VOC) Content... Compound (VOC) Content Limits for Automobile Refinish Coatings Coating category Grams VOC per liter Pounds VOC per gallon a Pretreatment wash primers 780 6.5 Primers/primer surfacers 580 4.8 Primer sealers 550...

  15. Evaluating UV/H₂O₂, UV/percarbonate, and UV/perborate for natural organic matter reduction from alternative water sources.

    Science.gov (United States)

    Sindelar, Hugo R; Brown, Mark T; Boyer, Treavor H

    2014-06-01

    Natural organic matter (NOM) continues to increase in drinking water sources due to many factors, including changes in land use and global climate. Water treatment facilities will need to evaluate the best treatment options to account for these higher NOM levels. The UV/H₂O₂ advanced oxidation process (AOP) is one treatment option that has shown success at reducing high levels of NOM. As a result, this study evaluated the UV/H₂O₂ for the reduction of NOM in a high NOM water matrix, the Florida Everglades. In addition to liquid H₂O₂, sodium percarbonate and sodium perborate were used as oxidants to evaluate their performance as alternatives to liquid H₂O₂. Results showed that all three oxidants were able to reduce aromatic carbon (UV₂₅₄) by 46-66% and dissolved organic carbon (DOC) by 11-19% at UV fluences of 2.6-2.7 J cm(-2) and an H₂O₂ dose of 100 mg L(-1). When the UV fluences were increased to 21.8-26.1 J cm(-2) at an H₂O₂ dose of 100 mg L(-1), UV₂₅₄ reduction increased to 79-97% and DOC to 42-82% for all three oxidants. All three oxidants performed statistically similar for UV₂₅₄ reduction. However, for DOC reduction, H₂O₂ performed statically better than both percarbonate and perborate, and perborate performed statistically better than percarbonate. While the UV/H₂O₂ AOP is effective for NOM reduction in high NOM waters, advances in electrical efficiency are needed to make it economically feasible. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Light dependency of VOC emissions from selected Mediterranean plant species

    Science.gov (United States)

    Owen, S. M.; Harley, P.; Guenther, A.; Hewitt, C. N.

    The light, temperature and stomatal conductance dependencies of volatile organic compound (VOC) emissions from ten plant species commonly found in the Mediterranean region were studied using a fully controlled leaf cuvette in the laboratory. At standard conditions of temperature and light (30°C and 1000 μmol m -2 s -1 PAR), low emitting species ( Arbutus unedo, Pinus halepensis, Cistus incanus, Cistus salvifolius, Rosmarinus officinalis and Thymus vulgaris) emitted between 0.1 and 5.0 μg (C) (total VOCs) g -1 dw h -1, a medium emitter ( Pinus pinea) emitted between 5 and 10 μg (C) g -1 dw h -1 and high emitters ( Cistus monspeliensis, Lavendula stoechas and Quercus sp.) emitted more than 10 μg (C) g -1 dw h -1. VOC emissions from all of the plant species investigated showed some degree of light dependency, which was distinguishable from temperature dependency. Emissions of all compounds from Quercus sp. were light dependent. Ocimene was one of several monoterpene compounds emitted by P. pinea and was strongly correlated to light. Only a fraction of monoterpene emissions from C. incanus exhibited apparent weak light dependency but emissions from this plant species were strongly correlated to temperature. Data presented here are consistent with past studies, which show that emissions are independent of stomatal conductance. These results may allow more accurate predictions of monoterpene emission fluxes from the Mediterranean region to be made.

  17. Heterogeneous Catalysts for VOC Oxidation from Red Mud and Bagasse Ash Carbon

    Science.gov (United States)

    Pande, Gaurav

    A range of VOC oxidation catalysts have been prepared in this study from agricultural and industrial waste as the starting point. The aim is to prepare catalysts with non-noble metal oxides as the active catalytic component (iron in red mud). The same active component was also supported on activated carbon obtained from unburned carbon in bagasse ash. Red mud which is an aluminum industry waste and rich in different phases of iron as oxide and hydroxide is used as the source for the catalytically active species. It is our aim to enhance the catalytic performance of red mud which though high in iron concentration has a low surface area and may not have the properties of an ideal catalyst by itself. In one of the attempts to enhance the catalytic performance, we have tried to leach red mud for which we have explored a range of leaching acids for effecting the leaching most efficiently and then precipitated the iron from the leachate as its hydroxide by precipitating with alkali solution followed by drying and calcination to give high surface area metal oxide material. Extensive surface characterization and VOC oxidation catalytic testing were performed for these solids. In a step to further enhance the catalytic activity towards oxidation, copper was introduced by taking another industrial waste from the copper tubing industry viz. the pickling acid. Copper has a more favourable redox potential making it catalytically more effective than iron. To make the mixed metal oxide, red mud leachate was mixed with the pickling acid in a pre-decided ratio before precipitating with alkali solution followed by drying and calcination as was done with the red mud leachate. The results from these experiments are encouraging. The temperature programmed reduction (TPR) of the solids show that the precipitate of red mud leachates show hydrogen uptake peak at a lower temperature than for just the calcined red mud. This could be due to the greatly enhanced surface area of the prepared

  18. Microbial compositions and metabolic interactions in one- and two-phase partitioning airlift bioreactors treating a complex VOC mixture.

    Science.gov (United States)

    Wu, Chao; Xu, Peilun; Xia, Yinfeng; Li, Wei; Li, Sujing; Wang, Xiangqian

    2017-09-01

    Engineered microbial ecosystems in bioscrubbers for the treatment of volatile organic compounds (VOCs) have been complicated by complex VOC mixtures from various industrial emissions. Microbial associations with VOC removal performance of the bioscrubbers are still not definitive. Here, one- and two-phase partitioning airlift bioreactors were used for the treatment of a complex VOC mixture. Microbial characteristics in both bioreactors were uncovered by high-throughput metagenomics sequencing. Results showed that dominant species with specialized VOC biodegradability were mainly responsible for high removal efficiency of relative individual VOC. Competitive enzyme inhibitions among the VOC mixture were closely related to the deterioration of removal performance for individual VOC. Relative to the mass transfer resistance, the specialized biodegrading functions of microbial inoculations and enzymatic interactions among individual VOC biodegradation also must be carefully evaluated to optimize the treatment of complex VOC mixtures in bioreactors.

  19. Volatile Organic Compound (VOC) Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up.

    Science.gov (United States)

    Rebollar-Perez, Georgette; Carretier, Emilie; Lesage, Nicolas; Moulin, Philippe

    2011-03-03

    Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs) (toluene-propylene-butadiene) from air was performed using a poly dimethyl siloxane (PDMS)/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10-4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID). The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  20. Volatile Organic Compound (VOC Removal by Vapor Permeation at Low VOC Concentrations: Laboratory Scale Results and Modeling for Scale Up

    Directory of Open Access Journals (Sweden)

    Philippe Moulin

    2011-03-01

    Full Text Available Petroleum transformation industries have applied membrane processes for solvent and hydrocarbon recovery as an economic alternative to reduce their emissions and reuse evaporated components. Separation of the volatile organic compounds (VOCs (toluene-propylene-butadiene from air was performed using a poly dimethyl siloxane (PDMS/α-alumina membrane. The experimental set-up followed the constant pressure/variable flow set-up and was operated at ~21 °C. The membrane is held in a stainless steel module and has a separation area of 55 × 10−4 m². Feed stream was set to atmospheric pressure and permeate side to vacuum between 3 and 5 mbar. To determine the performance of the module, the removed fraction of VOC was analyzed by Gas Chromatography/Flame Ionization Detector (GC/FID. The separation of the binary, ternary and quaternary hydrocarbon mixtures from air was performed at different flow rates and more especially at low concentrations. The permeate flux, permeance, enrichment factor, separation efficiency and the recovery extent of the membrane were determined as a function of these operating conditions. The permeability coefficients and the permeate flux through the composite PDMS-alumina membrane follow the order given by the Hildebrand parameter: toluene > 1,3-butadiene > propylene. The simulated data for the binary VOC/air mixtures showed fairly good agreement with the experimental results in the case of 1,3-butadiene and propylene. The discrepancies observed for toluene permeation could be minimized by taking into account the effects of the porous support and an influence of the concentration polarization. Finally, the installation of a 0.02 m2 membrane module would reduce 95% of the VOC content introduced at real concentration conditions used in the oil industry.

  1. Volatile organic compound (VOC) determination in working atmospheres; Determinacion de compuestos organicos volatiles (VOC) en ambiente laboral

    Energy Technology Data Exchange (ETDEWEB)

    Blass A, Georgina; Panama T, Luz A; Corrales C, Deyanira [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2003-07-01

    The present work describes, in a synthesized way, the implementation and application of procedures based on the normativity related to the subject of the volatile organic compounds (Volatile Organic Compounds VOC), that allow to sample, quantify and evaluate the present contamination in the working atmosphere of a refinery due to the fugitive emissions of VOC and other substances. In accordance with the corresponding normativity, more than 189 organic compounds denominated dangerous air polluting agents (Hazardous Air Pollutants, HAP) can be found in a working atmosphere, but they are the 11 main HAP that can be found in a refinery. In the present article the work made for the sampling and quantification of 5 of the 11 dangerous polluting agents of the air: benzene, toluene, xylene, iso-octane and naphthalene. [Spanish] El presente trabajo describe, de manera sintetizada, la implementacion y aplicacion de procedimientos basados en la normatividad relacionada al tema de los compuestos organicos volatiles (Volatil Organic Compounds, VOC), que permiten muestrear, cuantificar y evaluar la contaminacion presente en el ambiente laboral de una refineria debido a las emisiones fugitivas de VOC y otras sustancias. De acuerdo con la normatividad correspondiente, mas de 189 compuestos organicos denominados contaminantes peligrosos del aire (Hazardous Air Pollutants, HAP), pueden ser encontrados en un ambiente laboral, pero son 11 los principales HAP que pueden ser hallados en una refineria. En el presente articulo se informa el trabajo realizado para el muestreo y cuantificacion de 5 de los 11 contaminantes peligrosos del aire: benceno, tolueno, xileno, iso-octano y naftaleno.

  2. Efficacy of a dynamic collimator for overranging dose reduction in a second- and third-generation dual source CT scanner

    Energy Technology Data Exchange (ETDEWEB)

    Booij, Ronald; Dijkshoorn, Marcel L.; Straten, Marcel van [Erasmus MC, Department of Radiology and Nuclear Medicine, P.O. Box 2240, Rotterdam (Netherlands)

    2017-09-15

    The purpose of this study was to assess the efficacy of the renewed dynamic collimator in a third-generation dual source CT (DSCT) scanner and to determine the improvements over the second-generation scanner. Collimator efficacy is defined as the percentage overranging dose in terms of dose-length product (DLP) that is blocked by the dynamic collimator relative to the total overranging dose in case of a static collimator. Efficacy was assessed at various pitch values and different scan lengths. The number of additional rotations due to overranging and effective scan length were calculated on the basis of reported scanning parameters. On the basis of these values, the efficacy of the collimator was calculated. The second-generation scanner showed decreased performance of the dynamic collimator at increasing pitch. Efficacy dropped to 10% at the highest pitch. For the third-generation scanner the efficacy remained above 50% at higher pitch. Noise was for some pitch values slightly higher at the edge of the imaged volume, indicating a reduced scan range to reduce the overranging dose. The improved dynamic collimator in the third-generation scanner blocks the overranging dose for more than 50% and is more capable of shielding radiation dose, especially in high pitch scan modes. (orig.)

  3. Anthropogenic, Biogenic and Biomass Burning VOCs in the Southeast of the United States during SENEX

    Science.gov (United States)

    Graus, M.; Warneke, C.; De Gouw, J. A.; Trainer, M.; Aikin, K.; Brown, S. S.; Gilman, J.; Hanisco, T. F.; Holloway, J.; Kaiser, J.; Keutsch, F. N.; Lee, B.; Lerner, B. M.; Lopez-Hilfiker, F.; Min, K.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Thornton, J. A.; Veres, P. R.; Wolfe, G. M.

    2013-12-01

    The NOAA field study SENEX was designed to investigate the source strengths and spatial distribution of man-made air pollutants and natural emissions, their interaction to form secondary pollutants, and the atmospheric fate of aerosol and trace gases at the nexus of air quality and climate change. To this end the NOAA research aircraft WP-3D was equipped with instrumentation for the analysis of aerosol and trace gases and this flying atmospheric science laboratory performed 18 research flights over the Southeast of the United States in June and July 2013. VOCs such as isoprene and monoterpenes are released into the atmosphere by vegetation. Aromatics come from incomplete combustion of transportation fuels as well as from oil and natural gas production, and they are found in biomass burning plumes along with the distinct tracer acetonitrile. Oxygenated species such as alcohols, aldehydes and ketones are directly emitted from natural and anthropogenic sources and can be formed by photo oxidation of organic trace gases. At sufficiently high levels of nitrogen oxides, VOCs fuel the production of tropospheric ozone and they contribute to the formation and growth of secondary organic aerosol. Hence one key instrument onboard WP-3D was a PTR-MS for the time-resolved quantification of VOCs. The WP-3D performed plume study patterns downwind of coal- and gas-fired power plants. Isoprene concentrations were modulated in the high NOx regime as the plume evolved and the SENEX dataset will be used to constrain the chemistry in such plumes. City plumes of Atlanta (GA), Birmingham (AL), Indianapolis (IN), and St Louis (MO) showed modest concentrations of aromatics due to the decrease in hydrocarbon emissions from cars in comparison with previous studies. One flight leg targeted the plume of a large biofuel refinery, which will allow for an independent estimate of the primary emissions from this industry. A number of plumes of small fires in the study region were sampled as well as

  4. The colonial official as ethnographer; VOC documents as resources for social history in eastern Indonesia

    Directory of Open Access Journals (Sweden)

    Hans Hägerdal

    2012-10-01

    Full Text Available The present article departs from the inherent problems of grasping the voice of the subaltern other in a colonial context. While postcolonial theoreticians have occasionally spoken pessimistically about the possibilities of reconstructing the agency of dominated categories of non-Westerners, recent research on early Southeast Asia has on the contrary envisaged new lines of inquiry through an ingenious use of the extant sources, preferably through interdisciplinary communication. But can we use the colonial archive in order to highlight social history in non-literate societies such as those of eastern Indonesia where the colonial texts do not resonate with the indigenous ones? This article scrutinizes materials from the VOC (Vereenigde Oost-Indische Compagnie post in Kupang (1653-1800 in order to find data usable for such a history. It is argued that letters, reports, legal minutes, diaries, etcetera. have a good potential due to the regularity and minute detail of the record.

  5. Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited].

    Science.gov (United States)

    Pfäffle, Clara; Spahr, Hendrik; Hillmann, Dierck; Sudkamp, Helge; Franke, Gesa; Koch, Peter; Hüttmann, Gereon

    2017-03-01

    Full-field swept-source optical coherence tomography (FF-SS-OCT) was recently shown to allow new and exciting applications for imaging the human eye that were previously not possible using current scanning OCT systems. However, especially when using cameras that do not acquire data with hundreds of kHz frame rate, uncorrected phase errors due to axial motion of the eye lead to a drastic loss in image quality of the reconstructed volumes. Here we first give a short overview of recent advances in techniques and applications of parallelized OCT and finally present an iterative and statistical algorithm that estimates and corrects motion-induced phase errors in the FF-SS-OCT data. The presented algorithm is in many aspects adopted from the phase gradient autofocus (PGA) method, which is frequently used in synthetic aperture radar (SAR). Following this approach, the available phase errors can be estimated based on the image information that remains in the data, and no parametrization with few degrees of freedom is required. Consequently, the algorithm is capable of compensating even strong motion artifacts. Efficacy of the algorithm was tested on simulated data with motion containing varying frequency components. We show that even in strongly blurred data, the actual image information remains intact, and the algorithm can identify the phase error and correct it. Furthermore, we use the algorithm to compensate real phase error in FF-SS-OCT imaging of the human retina. Acquisition rates can be reduced by a factor of three (from 60 to 20 kHz frame rate) with an image quality that is even higher compared to uncorrected volumes recorded at the maximum acquisition rate. The presented algorithm for axial motion correction decreases the high requirements on the camera frame rate and thus brings FF-SS-OCT closer to clinical applications.

  6. Implementation of Similarity Based Kriging in Open Source Software and Application to Uncertainty Quantification and Reduction in Hydrogeological Inversion

    Science.gov (United States)

    Komara, R.; Ginsbourger, D.

    2014-12-01

    We present the implementation of Similarity Based Kriging (SBK). This approach extends Gaussian process regression (GPR) methods, typically restricted to Euclidean spaces, to spaces that are non-Euclidean or perhaps even non-metric. SBK was inspired by problems in aquifer modeling, where inputs of numerical simulations are typically curves and parameter fields, and predicting scalar or vector outputs by Kriging with such very high-dimensional inputs may seem not feasible at first. SBK combines ideas from the distance-based set-up of Scheidt and Caers (2009) with GPR and allows calculating Kriging predictions based only on similarities between inputs rather than on their high-dimensional representation. Written in open source code, this proposed approach includes automated construction of SBK models and provides diagnostics to assess model quality both in terms of covariance fitting and internal/external prediction validation. Covariance hyperparameters can be estimated both by maximum likelihood and leave-one-out cross validation relying in both cases on efficient formulas and a hybrid genetic optimization algorithm using derivatives. The determination of the best dimension for Classical multidimensional scaling (MDS) and non-metric MDS of the data will be investigated. Application of this software to real life data examples in Euclidean and non-Euclidean (dis)similarity settings will be covered and touch on aquifer modeling, hydrogeological forecasting, and sequential inverse problem solving. In the last case, a novel approach where a variant of the expected improvement criterion is used for choosing several points at a time will be presented. This part of the method and the previous covariance hyperparameter estimation parallelize naturally and we demonstrate how to save computation time by optimally distributing function evaluations over multiple cores or processors.

  7. Critical Aspects of Heme-Peroxo-Cu Complex Structure and Nature of Proton Source Dictate Metal-O(peroxo) Breakage versus Reductive O-O Cleavage Chemistry.

    Science.gov (United States)

    Adam, Suzanne M; Garcia-Bosch, Isaac; Schaefer, Andrew W; Sharma, Savita K; Siegler, Maxime A; Solomon, Edward I; Karlin, Kenneth D

    2017-01-11

    The 4H(+)/4e(-) reduction of O2 to water, a key fuel-cell reaction also carried out in biology by oxidase enzymes, includes the critical O-O bond reductive cleavage step. Mechanistic investigations on active-site model compounds, which are synthesized by rational design to incorporate systematic variations, can focus on and resolve answers to fundamental questions, including protonation and/or H-bonding aspects, which accompany electron transfer. Here, we describe the nature and comparative reactivity of two low-spin heme-peroxo-Cu complexes, LS-4DCHIm, [(DCHIm)F8Fe(III)-(O2(2-))-Cu(II)(DCHIm)4](+), and LS-3DCHIm, [(DCHIm)F8Fe(III)-(O2(2-))-Cu(II)(DCHIm)3](+) (F8 = tetrakis(2,6-difluorophenyl)-porphyrinate; DCHIm = 1,5-dicyclohexylimidazole), toward different proton (4-nitrophenol and [DMF·H(+)](CF3SO3(-))) (DMF = dimethyl-formamide) or electron (decamethylferrocene (Fc*)) sources. Spectroscopic reactivity studies show that differences in structure and electronic properties of LS-3DCHIm and LS-4DCHIm lead to significant differences in behavior. LS-3DCHIm is resistant to reduction, is unreactive toward weakly acidic 4-NO2-phenol, and stronger acids cleave the metal-O bonds, releasing H2O2. By contrast, LS-4DCHIm forms an adduct with 4-NO2-phenol, which includes an H-bond to the peroxo O-atom distal to Fe (resonance Raman (rR) spectroscopy and DFT). With addition of Fc* (2 equiv overall required), O-O reductive cleavage occurs, giving water, Fe(III), and Cu(II) products; however, a kinetic study reveals a one-electron rate-determining process, ket = 1.6 M(-1) s(-1) (-90 °C). The intermediacy of a high-valent [(DCHIm)F8Fe(IV)═O] species is thus implied, and separate experiments show that one-electron reduction-protonation of [(DCHIm)F8Fe(IV)═O] occurs faster (ket2 = 5.0 M(-1) s(-1)), consistent with the overall postulated mechanism. The importance of the H-bonding interaction as a prerequisite for reductive cleavage is highlighted.

  8. Volatile organic compounds (VOCs) in surface coating materials: Their compositions and potential as an alternative fuel.

    Science.gov (United States)

    Dinh, Trieu-Vuong; Choi, In-Young; Son, Youn-Suk; Song, Kyu-Yong; Sunwoo, Young; Kim, Jo-Chun

    2016-03-01

    A sampling system was designed to determine the composition ratios of VOCs emitted from 31 surface coating materials (SCMs). Representative architectural, automotive, and marine SCMs in Korea were investigated. Toluene, ethylbenzene, and xylene were the predominant VOCs. The VOC levels (wt%) from automotive SCMs were significantly higher than those from architectural and marine paints. It was found that target SCMs comprised mainly VOCs with 6-10 carbon atoms in molecules, which could be adsorbed by activated carbon. The saturated activated carbon which had already adsorbed toluene, ethylbenzene, and m-xylene was combusted. The saturated activated carbon was more combustible than new activated carbon because it comprised inflammable VOCs. Therefore, it could be an alternative fuel when using in a "fuelization system". To use the activated carbon as a fuel, a control technology of VOCs from a coating process was also designed and introduced. Copyright © 2015. Published by Elsevier Ltd.

  9. Theoretical study of simultaneous water and VOCs adsorption and desorption in a silica gel rotor

    DEFF Research Database (Denmark)

    Zhang, G.; Zhang, Y.F.; Fang, Lei

    2008-01-01

    One-dimensional partial differential equations were used to model the simultaneous water and VOC (Volatile Organic Compound) adsorption and desorption in a silica gel rotor which was recommended for indoor air cleaning. The interaction among VOCs and moisture in the adsorption and desorption...... process was neglected in the model as the concentrations of VOC pollutants in typical indoor environment were much lower than that of moisture and the adsorbed VOCs occupied only a minor portion of adsorption capacity of the rotor. Consequently VOC transfer was coupled with heat and moisture transfer only...... by the temperatures of the rotor and the air stream. The VOC transfer equations were solved by discretizing them into explicit up-wind finite differential equations. The model was validated with experimental data. The calculated results suggested that the regeneration time designed for dehumidification may...

  10. Ambient air/near-field measurements of methane and Volatile Organic Compounds (VOCs) from a natural gas facility in Northern Europe

    Science.gov (United States)

    Baudic, Alexia; Gros, Valérie; Bonsang, Bernard; Baisnee, Dominique; Vogel, Félix; Yver Kwok, Camille; Ars, Sébastien; Finlayson, Andrew; Innocenti, Fabrizio; Robinson, Rod

    2015-04-01

    Since the 1970's, the natural gas consumption saw a rapid growth in large urban centers, thus becoming an important energy resource to meet continuous needs of factories and inhabitants. Nevertheless, it can be a substantial source of methane (CH4) and pollutants in urban areas. For instance, we have determined that about 20% of Volatile Organic Compounds (VOCs) in downtown Paris are originating from this emission source (Baudic, Gros et al., in preparation). Within the framework of the "Fugitive Methane Emissions" (FuME) project (Climate-KIC, EIT); 2-weeks gas measurements were conducted at a gas compressor station in Northern Europe. Continuous ambient air measurements of methane and VOCs concentrations were performed using a cavity ring-down spectrometer (model G2201, Picarro Inc., Santa Clara, USA) and two portable GC-FID (Chromatotec, Saint-Antoine, France), respectively. On-site near-field samplings were also carried out at the source of two pipelines using stainless steel flasks (later analyzed with a laboratory GC-FID). The objective of this study aims to use VOCs as additional tracers in order to better characterize the fugitive methane emissions in a complex environment, which can be affected by several urban sources (road-traffic, others industries, etc.). Moreover, these measurements have allowed determining the chemical composition of this specific source. Our results revealed that the variability of methane and some VOCs was (rather) well correlated, especially for alkanes (ethane, propane, etc.). An analysis of selected events with strong concentrations enhancement was performed using ambient air measurements; thus allowing the preliminary identification of different emission sources. In addition, some flasks were also sampled in Paris to determine the local natural gas composition. A comparison between both was then performed. Preliminary results from these experiments will be presented here.

  11. Source characterization of volatile organic compounds in the Colorado Northern Front Range Metropolitan Area during spring and summer 2015

    Science.gov (United States)

    Abeleira, A.; Pollack, I. B.; Sive, B.; Zhou, Y.; Fischer, E. V.; Farmer, D. K.

    2017-03-01

    Hourly measurements of 46 volatile organic compounds (VOCs) from the Boulder Atmospheric Observatory in Erie, CO, were collected over 16 weeks in spring and summer 2015. Average VOC reactivity (1.2 s-1 in spring and 2.4 s-1 in summer) was lower than most other U.S. urban sites. Positive matrix factorization analysis identified five VOC factors in the spring, corresponding to sources from (1) long-lived oil and natural gas (ONG-long lived), (2) short-lived oil and natural gas (ONG-short lived), (3) traffic, (4) background, and (5) secondary chemical production. In the summer, an additional biogenic factor was dominated by isoprene. While ONG-related VOCs were the single largest contributor (40-60%) to the calculated VOC reactivity with hydroxyl radicals (OH) throughout the morning in both spring and summer, the biogenic factor substantially enhanced afternoon and evening (2-10 P.M. local time) VOC reactivity (average of 21%; maxima of 49% of VOC reactivity) during summertime. These results contrast with a previous summer 2012 campaign which showed that biogenics contributed only 8% of VOC reactivity on average. The interannual differences suggest that the role of biogenic VOCs in the Colorado Northern Front Range Metropolitan Area (NFRMA) varies with environmental conditions such as drought stress. Overall, the NFRMA was more strongly influenced by ONG sources of VOCs than other urban and suburban regions in the U.S.

  12. Initial Analysis of VOCs Speciation in CREATE Emissions Inventory using the MAPS-Seoul Aircraft Field Campaign

    Science.gov (United States)

    Bu, C.; Woo, J. H.; Lee, Y.; Kim, J.; Choi, K. C.; Kim, Y.; Kim, J.; Jang, Y. K.; Kim, S.

    2016-12-01

    As the first international cooperative air quality field study, the MAPS-Seoul (Megacity Air Pollution Studies-Seoul) aircraft mission was conducted in May - June 2016 over the South Korea, to understand of climate and atmospheric environment. The aircraft carried observation instruments for measurements of GHGs, ozone and its precursors, aerosols, and chemical tracers. The CREATE (Comprehensive Regional Emissions inventory for Atmospheric Environment) emissions inventory and SMOKE-Asia emission processing system were used to support chemical forecasting and to serve as a priori for evaluation. Initial results of comparison studies show large discrepancies in VOC species over the South Korea - especially over urban regions. Several VOC species observed high near megacities and petro-chemical plants but under-predicted by chemical transport models (CTMs) - possibly due to relatively low emissions. The chemical speciation profiles and emissions inventory for each emission sources, therefore, have to be re-visited to improve emissions information. In this study, we have; 1) re-examined our emissions inventory and emission speciation processes, 2) and tried to find possible missing sources and alternative chemical speciation profiles, to improve our modelling emissions inventory. Initial review of the mapping and classification profiles, the original US chemical speciation profiles were found to be low in partitioning painting and surface coating sources, although they are the very significant contributors. Unlike other major national cities in China, Shanghai's VOC emissions fraction seems very similar to that of Seoul. Continuous analysis of major urban and industrial areas of the country will be presented at site.Acknowledgements : This subject is supported by Korea Ministry of Environment as "Climate Change Correspondence Program". This work was supported by a grant from the National Institute of Environment Research (NIER), funded by the Ministry of Environment

  13. Secondary organic aerosol formation through fog processing of VOCs

    Science.gov (United States)

    Herckes, P.; Hutchings, J. W.

    2010-07-01

    Volatile Organic Compounds (VOCs) including benzene, toluene, ethylbenzene and xylenes (BTEX) have been determined in highly concentrated amounts (>1 ug/L) in intercepted clouds in northern Arizona (USA). These VOCs are found in concentrations much higher than predicted by partitioning alone. The reactivity of BTEX in the fog/cloud aqueous phase was investigated through laboratory studies. BTEX species showed fast degradation in the aqueous phase in the presence of peroxides and light. Observed half-lives ranged from three and six hours, substantially shorter than the respective gas phase half-lives (several days). The observed reaction rates were on the order of 1 ppb/min but decreased substantially with increasing concentrations of organic matter (TOC). The products of BTEX oxidation reactions were analyzed using HPLC-UV and LCMS. The first generation of products identified included phenol and cresols which correspond to the hydroxyl-addition reaction to benzene and toluene. Upon investigating of multi-generational products, smaller, less volatile species are predominant although a large variety of products is found. Most reaction products have substantially lower vapor pressure and will remain in the particle phase upon droplet evaporation. The SOA generation potential of cloud and fog processing of BTEX was evaluated using simple calculations and showed that in ideal situations these reactions could add up to 9% of the ambient aerosol mass. In more conservative scenarios, the contribution of the processing of BTEX was around 1% of ambient aerosol concentrations. Overall, cloud processing of VOC has the potential to contribute to the atmospheric aerosol mass. However, the contribution will depend upon many factors such as the irradiation, organic matter content in the droplets and droplet lifetime.

  14. Exchange of Volatile Organic Compounds (VOCs) at the Atmosphere-Soil Interface under Ambient Conditions: a Coated-Wall Flow Tube Study

    Science.gov (United States)

    Su, H.; Li, G.; Kuhn, U.; Meusel, H.; Poeschl, U.; Shao, M.; Cheng, Y.

    2016-12-01

    Volatile organic compounds (VOCs) represent a large fraction of organic carbon in the atmosphere and play an important role in atmospheric chemistry. Deep insight into the VOCs-related tropospheric chemistry requires a profound understanding of sources and sinks of different VOCs species. Multiphase processes on the surface of soil and airborne soil-derived particles have been suggested as an important mechanism for the production/removal of atmospheric trace gases and aerosols. In this work, we investigated the exchange of 13 species of VOCs at the atmosphere-soil interface using a coated-wall flow tube system coupled to a PTR-MS, under ambient conditions at an urban background site in Beijing. The results show that most of the species tend to be absorbed/adsorbed and further retained or converted into other products by soil (net influx into soil) while formic acid can most probably be produced by soil either due to chemical transformation of other absorbed/adsorbed species or emission from soil itself (net efflux from soil). For the species showing noticeable uptake, their uptake coefficients display a gradually decrease along the measurement time, suggesting a progressive saturation of the soil surface. The uptake of several species (e.g., methanol, acetic acid and formaldehyde), however, don't exhibit marked dependence on time. Correlation studies show a dependence of uptake on temperature or relative humidity for several species: the uptake of methanol, acetic acid and methyl ethyl ketone (MEK) decreases with increasing temperature; and the uptake of isoprene, acetaldehyde and methyl vinyl ketone/methacrolein (MVK+MACR) increases with increasing relative humidity. Based on our results, mineral soil serves as a sink rather than a source for most VOC species.

  15. Monte Carlo study on secondary neutrons in passive carbon-ion radiotherapy: identification of the main source and reduction in the secondary neutron dose.

    Science.gov (United States)

    Yonai, Shunsuke; Matsufuji, Naruhiro; Kanai, Tatsuaki

    2009-10-01

    Recent successful results in passive carbon-ion radiotherapy allow the patient to live for a longer time and allow younger patients to receive the radiotherapy. Undesired radiation exposure in normal tissues far from the target volume is considerably lower than that close to the treatment target, but it is considered to be non-negligible in the estimation of the secondary cancer risk. Therefore, it is very important to reduce the undesired secondary neutron exposure in passive carbon-ion radiotherapy without influencing the clinical beam. In this study, the source components in which the secondary neutrons are produced during passive carbon-ion radiotherapy were identified and the method to reduce the secondary neutron dose effectively based on the identification of the main sources without influencing the clinical beam was investigated. A Monte Carlo study with the PHITS code was performed by assuming the beamline at the Heavy-Ion Medical Accelerator in Chiba (HIMAC). At first, the authors investigated the main sources of secondary neutrons in passive carbon-ion radiotherapy. Next, they investigated the reduction in the neutron dose with various modifications of the beamline device that is the most dominant in the neutron production. Finally, they investigated the use of an additional shield for the patient. It was shown that the main source is the secondary neutrons produced in the four-leaf collimator (FLC) used as a precollimator at HIAMC, of which contribution in the total neutron ambient dose equivalent is more than 70%. The investigations showed that the modification of the FLC can reduce the neutron dose at positions close to the beam axis by 70% and the FLC is very useful not only for the collimation of the primary beam but also the reduction in the secondary neutrons. Also, an additional shield for the patient is very effective to reduce the neutron dose at positions farther than 50 cm from the beam axis. Finally, they showed that the neutron dose can be

  16. VoCS : Sistema de almacenamiento voluntario en la nube

    OpenAIRE

    Schiavón Raineri, Ignacio Nicolás

    2012-01-01

    La computación en la nube responde a las necesidades del aumento de dispositivos conectados a Internet y el creciente volumen de datos manejados, ofreciendo acceso ubicuo y transparente a la información de forma segura. Esto ha tenido como consecuencia la apertura del mercado, ofreciendo muchas aplicaciones basadas en la nube como SkyDrive, Google Drive o Dropbox. VoCS (Volunteer Cloud Storage) es un sistema de almacenamiento voluntario en la nube de código abierto y seguro, que pretende ofre...

  17. Sodium and Food Sources

    Science.gov (United States)

    ... Sources Top 10 Sources of Sodium How to Reduce Sodium Sodium Reduction Resources for Everyone Sodium Reduction Fact ... in processed food [PDF-867K] and how to reduce sodium. Sodium Reduction Is Challenging Types of food matter: ...

  18. Evaluation of non-point source pollution reduction by applying best management practices using a SWAT model and QuickBird high resolution satellite imagery.

    Science.gov (United States)

    Lee, MiSeon; Park, GeunAe; Park, MinJi; Park, JongYoon; Lee, JiWan; Kim, SeongJoon

    2010-01-01

    This study evaluated the reduction effect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2 small agricultural watershed using a SWAT (Soil and Water Assessment Tool) model. Two meter QuickBird land use data were prepared for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP), total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcliffe model efficiency was 0.63 for the streamflow and the coefficients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP, respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian buffer system, the regulation of Universal Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed.

  19. Termination of light-water reactor core-melt accidents with a chemical core catcher: the core-melt source reduction system (COMSORS)

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, C.W.; Parker, G.W.; Rudolph, J.C.; Osborne-Lee, I.W. [Oak Ridge National Lab., TN (United States); Kenton, M.A. [Dames and Moore, Westmont, IL (United States)

    1996-09-01

    The Core-Melt Source Reduction System (COMSORS) is a new approach to terminate light-water reactor core melt accidents and ensure containment integrity. A special dissolution glass is placed under the reactor vessel. If core debris is released onto the glass, the glass melts and the debris dissolves into the molten glass, thus creating a homogeneous molten glass. The molten glass, with dissolved core debris, spreads into a wide pool, distributing the heat for removal by radiation to the reactor cavity above or by transfer to water on top of the molten glass. Expected equilibrium glass temperatures are approximately 600 degrees C. The creation of a low-temperature, homogeneous molten glass with known geometry permits cooling of the glass without threatening containment integrity. This report describes the technology, initial experiments to measure key glass properties, and modeling of COMSORS operations.

  20. FEV manoeuvre induced changes in breath VOC compositions: an unconventional view on lung function tests

    Science.gov (United States)

    Sukul, Pritam; Schubert, Jochen K.; Oertel, Peter; Kamysek, Svend; Taunk, Khushman; Trefz, Phillip; Miekisch, Wolfram

    2016-06-01

    Breath volatile organic compound (VOC) analysis can open a non-invasive window onto pathological and metabolic processes in the body. Decades of clinical breath-gas analysis have revealed that changes in exhaled VOC concentrations are important rather than disease specific biomarkers. As physiological parameters, such as respiratory rate or cardiac output, have profound effects on exhaled VOCs, here we investigated VOC exhalation under respiratory manoeuvres. Breath VOCs were monitored by means of real-time mass-spectrometry during conventional FEV manoeuvres in 50 healthy humans. Simultaneously, we measured respiratory and hemodynamic parameters noninvasively. Tidal volume and minute ventilation increased by 292 and 171% during the manoeuvre. FEV manoeuvre induced substance specific changes in VOC concentrations. pET-CO2 and alveolar isoprene increased by 6 and 21% during maximum exhalation. Then they decreased by 18 and 37% at forced expiration mirroring cardiac output. Acetone concentrations rose by 4.5% despite increasing minute ventilation. Blood-borne furan and dimethyl-sulphide mimicked isoprene profile. Exogenous acetonitrile, sulphides, and most aliphatic and aromatic VOCs changed minimally. Reliable breath tests must avoid forced breathing. As isoprene exhalations mirrored FEV performances, endogenous VOCs might assure quality of lung function tests. Analysis of exhaled VOC concentrations can provide additional information on physiology of respiration and gas exchange.

  1. VOC-Induced Flexing of Single and Multilayer Polyethylene Films As Gas Sensors.

    Science.gov (United States)

    Alipour, Nazanin; Andersson, Richard L; Olsson, Richard T; Gedde, Ulf W; Hedenqvist, Mikael S

    2016-04-20

    The differential swelling and bending of multilayer polymeric films due to the dissimilar uptake of volatile organic compounds (VOCs; n-hexane, limonene) in the different layers was studied. Motions of thin polyethylene films triggered by the penetrant were investigated to learn more about how their deformation is related to VOC absorption. Single layers of metallocene or low-density polyethylene, and multilayers (2-288 layers) of these in alternating positions were considered. Single-, 24-, and 288-layer films displayed no motion when uniformly subjected to VOCs, but they could display simple curving modes when only one side of the film was wetted with a liquid VOC. Two-layer films displayed simple bending when uniformly subjected to VOCs due to the different swelling in the two layers, but when the VOC was applied to only one side of the film, more complex modes of motion as well as dynamic oscillations were observed (e.g., constant amplitude wagging at 2 Hz for ca. 50 s until all the VOC had evaporated). Diffusion modeling was used to study the transport behavior of VOCs inside the films and the different bending modes. Finally a prototype VOC sensor was developed, where the reproducible curving of the two-layer film was calibrated with n-hexane. The sensor is simple, cost-efficient, and nondestructive and requires no electricity.

  2. Biochar for volatile organic compound (VOC) removal: Sorption performance and governing mechanisms.

    Science.gov (United States)

    Zhang, Xueyang; Gao, Bin; Zheng, Yulin; Hu, Xin; Creamer, Anne Elise; Annable, Michael D; Li, Yuncong

    2017-12-01

    Sorption is one of the most efficient and low cost strategies for volatile organic compound (VOC) removal, but VOC sorption by biochar has seen limited research. In this work, gas phase sorption experiments were conducted to determine the sorption potential and mechanisms of VOCs onto biochar. A total of 15 biochars produced from 5 common feedstocks at 300, 450, and 600°C were evaluated as sorbents. Three common VOCs (acetone, cyclohexane, and toluene) were chosen as sorbates. The results showed that all the tested biochars had VOC sorption capacity in the range of 5.58-91.2mgg-1. The sorption capacities were mainly influenced by both the surface area of biochar and its noncarbonized organic matter content. The vapor sorption process was exothermic, and the removal of VOCs by the biochars decreased with increasing feedstock temperature. Both the physical adsorption and partition mechanisms played important roles in controlling the VOC removal by the biochars. Biochar maintained its VOC removal ability after five consecutive sorption-desorption cycles, which indicated good reusability. Findings of this work suggest that biochar is a promising alternative sorbent for gaseous VOC removal. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Source Reduction Behavior as an Independent Measurement of the Impact of a Public Health Education Campaign in an Integrated Vector Management Program for the Asian Tiger Mosquito

    Directory of Open Access Journals (Sweden)

    Daniel Strickman

    2011-05-01

    Full Text Available The goal of this study was to evaluate the effectiveness of a public health educational campaign to reduce backyard mosquito-larval habitats. Three communities each, within two New Jersey counties, were randomly selected to receive: (1 both education and mosquito control, (2 education only, and (3 no education or mosquito control. Four separate educational events included a 5-day elementary school curriculum in the spring, and three door to door distributions of educational brochures. Before and after each educational event, the numbers of mosquito-larval container habitats were counted in 50 randomly selected homes per study area. Container surveys allowed us to measure source reduction behavior. Although we saw reductions in container habitats in sites receiving education, they were not significantly different from the control. Our results suggest that traditional passive means of public education, which were often considered the gold standard for mosquito control programs, are not sufficient to motivate residents to reduce backyard mosquito-larval habitats.

  4. Determination of source contributions to ambient volatile organic compound concentrations in Berlin

    NARCIS (Netherlands)

    Thijsse, T.R.; Oss, R.F. van; Lenschow, P.

    1999-01-01

    During three measuring campaigns in June, July, and August 1996, volatile organic compound (VOC) concentrations were measured at a rural background site, a city residential site, and a street site in Berlin. In addition, samples were taken near relevant sources of VOCs. The measurements covered the

  5. Nine years of global hydrocarbon emissions based on source inversion of OMI formaldehyde observations

    NARCIS (Netherlands)

    Bauwens, Maite; Stavrakou, Trissevgeni; Müller, Jean François; De Smedt, Isabelle; Van Roozendael, Michel; Van Der Werf, Guido R.; Wiedinmyer, Christine; Kaiser, Johannes W.; Sindelarova, Katerina; Guenther, Alex

    2016-01-01

    As formaldehyde (HCHO) is a high-yield product in the oxidation of most volatile organic compounds (VOCs) emitted by fires, vegetation, and anthropogenic activities, satellite observations of HCHO are well-suited to inform us on the spatial and temporal variability of the underlying VOC sources. The

  6. BioXTAS RAW: improvements to a free open-source program for small-angle X-ray scattering data reduction and analysis.

    Science.gov (United States)

    Hopkins, Jesse Bennett; Gillilan, Richard E; Skou, Soren

    2017-10-01

    BioXTAS RAW is a graphical-user-interface-based free open-source Python program for reduction and analysis of small-angle X-ray solution scattering (SAXS) data. The software is designed for biological SAXS data and enables creation and plotting of one-dimensional scattering profiles from two-dimensional detector images, standard data operations such as averaging and subtraction and analysis of radius of gyration and molecular weight, and advanced analysis such as calculation of inverse Fourier transforms and envelopes. It also allows easy processing of inline size-exclusion chromatography coupled SAXS data and data deconvolution using the evolving factor analysis method. It provides an alternative to closed-source programs such as Primus and ScÅtter for primary data analysis. Because it can calibrate, mask and integrate images it also provides an alternative to synchrotron beamline pipelines that scientists can install on their own computers and use both at home and at the beamline.

  7. Oxidative capacity of the Mexico City atmosphere – Part 1: A radical source perspective

    Directory of Open Access Journals (Sweden)

    R. Volkamer

    2010-07-01

    found already at 10:00 a.m., i.e., more than 2.5 h before solar noon. O3/alkene reactions are indirectly responsible for ~33% of these radicals. Our measurements and analysis comprise a database that enables testing of the representation of radical sources and radical chain reactions in photochemical models.

    Since the photochemical processing of pollutants in the MCMA is radical limited, our analysis identifies the drivers for ozone and SOA formation. We conclude that reductions in VOC emissions provide an efficient opportunity to reduce peak concentrations of these secondary pollutants, because (1 about 70% of radical production is linked to VOC precursors; (2 lowering the VOC/NOx ratio has the further benefit of reducing the radical re-cycling efficiency from radical chain reactions (chemical amplification of radical sources; (3 a positive feedback is identified: lowering the rate of radical production from organic precursors also reduces that from inorganic precursors, like ozone, as pollution export from the MCMA caps the amount of ozone that accumulates at a lower rate inside the MCMA. Continued VOC reductions will in the future result in decreasing peak concentrations of ozone and SOA in the MCMA.

  8. Alcohol induced alterations to the human fecal VOC metabolome.

    Science.gov (United States)

    Couch, Robin D; Dailey, Allyson; Zaidi, Fatima; Navarro, Karl; Forsyth, Christopher B; Mutlu, Ece; Engen, Phillip A; Keshavarzian, Ali

    2015-01-01

    Studies have shown that excessive alcohol consumption impacts the intestinal microbiota composition, causing disruption of homeostasis (dysbiosis). However, this observed change is not indicative of the dysbiotic intestinal microbiota function that could result in the production of injurious and toxic products. Thus, knowledge of the effects of alcohol on the intestinal microbiota function and their metabolites is warranted, in order to better understand the role of the intestinal microbiota in alcohol associated organ failure. Here, we report the results of a differential metabolomic analysis comparing volatile organic compounds (VOC) detected in the stool of alcoholics and non-alcoholic healthy controls. We performed the analysis with fecal samples collected after passage as well as with samples collected directly from the sigmoid lumen. Regardless of the approach to fecal collection, we found a stool VOC metabolomic signature in alcoholics that is different from healthy controls. The most notable metabolite alterations in the alcoholic samples include: (1) an elevation in the oxidative stress biomarker tetradecane; (2) a decrease in five fatty alcohols with anti-oxidant property; (3) a decrease in the short chain fatty acids propionate and isobutyrate, important in maintaining intestinal epithelial cell health and barrier integrity; (4) a decrease in alcohol consumption natural suppressant caryophyllene; (5) a decrease in natural product and hepatic steatosis attenuator camphene; and (6) decreased dimethyl disulfide and dimethyl trisulfide, microbial products of decomposition. Our results showed that intestinal microbiota function is altered in alcoholics which might promote alcohol associated pathologies.

  9. In situ treatment of VOCs by recirculation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, R.L.; Webb, O.F.; Ally, M.R.; Sanford, W.E. [Oak Ridge National Lab., TN (US); Kearl, P.M.; Zutman, J.L. [Oak Ridge National Lab., Grand Junction, CO (US)

    1993-06-01

    The project described herein was conducted by Oak Ridge National Laboratory (ORNL) to identify processes and technologies developed in Germany that appeared to have near-term potential for enhancing the cleanup of volatile organic compound (VOC) contaminated soil and groundwater at DOE sites. Members of the ORNL research team identified and evaluated selected German technologies developed at or in association with the University of Karlsruhe (UoK) for in situ treatment of VOC contaminated soils and groundwater. Project activities included contacts with researchers within three departments of the UoK (i.e., Applied Geology, Hydromechanics, and Soil and Foundation Engineering) during fall 1991 and subsequent visits to UoK and private industry collaborators during February 1992. Subsequent analyses consisted of engineering computations, groundwater flow modeling, and treatment process modeling. As a result of these project efforts, two processes were identified as having near-term potential for DOE: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well. This document was prepared to summarize the methods and results of the assessment activities completed during the initial year of the project. The project is still ongoing, so not all facets of the effort are completely described in this document. Recommendations for laboratory and field experiments are provided.

  10. Photocatalytic oxidation of VOC, nitrogen oxide and atrazine using titanium dioxide modified with perovskite materials

    Science.gov (United States)

    Vajifdar, Kayzad Jimmy

    Photocatalysis utilizes near-UV or visible light to break down organic pollutants into innocuous compounds at room temperatures and has gained much attention in air and water pollution control. Chapter 1 introduces the use of semiconducting optical crystals as an additive to a photocatalyst. The perovskite optical material BaTiO3 (band gap of 3.7-3.8 eV) is found to increase VOC destruction when black light is used. The best composition found is 0.1 wt% BaTiO3 with the balance being TiO2. This photocatalyst increases perchloroethylene (PCE) conversion by 12% to 32% for space times between 1.4 and 17.2 seconds and inlet concentrations of 40 to 130 ppm with a 4 W black light. The average enhancement is approximately 25%. For butyraldehyde conversion the maximum enhancement is 20% at 130 ppm in 3.6 seconds. The UV/Vis spectroscopy data indicate a lower absorbance with the additive. The reaction parameters studied are space velocity, inlet concentration and light source. Oxidation by-products are identified using a GCMS. Chapter 2 introduces photocatalysis as an emerging green technology for environmental protection to oxidize NOx. The experimental results indicate that the coating of photocatalytic materials on concrete pavements can harvest the light energy for NOx pollution control. The photocatalytic coating has the potential to reduce NOx concentration in the atmosphere economically, nearly maintenance-free. NOx will be oxidized to nitric acid, neutralized by the alkaline base materials in concrete, and washed away by rain. The reduction in the number of high ozone days can be significant to allow sustainable economic developments in the many ozone-non-attainment areas worldwide. One of the foci will be pavement coated with photocatalysts enhanced with perovskites/ferroelectric optical crystals such as BaTiO3 via increased transmission/scattering and electron-hole pair stabilization. The developed technology can be transferred to the cement and coating industries

  11. Exhaled breath and oral cavity VOCs as potential biomarkers in oral cancer patients.

    Science.gov (United States)

    Bouza, M; Gonzalez-Soto, J; Pereiro, R; de Vicente, J C; Sanz-Medel, A

    2017-03-01

    Corporal mechanisms attributed to cancer, such as oxidative stress or the action of cytochrome P450 enzymes, seem to be responsible for the generation of a variety of volatile organic compounds (VOCs) that could be used as non-invasive diagnosis biomarkers. The present work presents an attempt to use VOCs from exhaled breath and oral cavity air as biomarkers for oral squamous cell carcinoma (OSCC) patients. A total of 52 breath samples were collected (in 3 L Tedlar bags) from 26 OSCC patients and 26 cancer-free controls. The samples were analyzed using solid-phase microextraction followed by gas chromatography-mass spectrometry detection. Different statistical strategies (e.g., Icoshift, SIMCA, LDA, etc) were used to classify the analytical data. Results revealed that compounds such as undecane, dodecane, decanal, benzaldehyde, 3,7-dimethyl undecane, 4,5-dimethyl nonane, 1-octene, and hexadecane had relevance as possible biomarkers for OSCC. LDA classification with these compounds showed well-defined clusters for patients and controls (non-smokers and smokers). In addition to breath analysis, preliminary studies were carried out to evaluate the possibility of lesion-surrounded air (analyzed OSCC tumors are in the oral cavity) as a source of biomarkers. The oral cavity location of the squamous cell carcinoma tumors constitutes an opportunity to non-invasively collect the air surrounding the lesion. Small quantities (20 ml) of air collected in the oral cavity were analyzed using the above methodology. Results showed that aldehydes present in the oral cavity might constitute potential OSCC biomarkers.

  12. VOC species and emission inventory from vehicles and their SOA formation potentials estimation in Shanghai, China

    Science.gov (United States)

    Huang, C.; Wang, H. L.; Li, L.; Wang, Q.; Lu, Q.; de Gouw, J. A.; Zhou, M.; Jing, S. A.; Lu, J.; Chen, C. H.

    2015-10-01

    Volatile organic compound (VOC) species from vehicle exhausts and gas evaporation were investigated by chassis dynamometer and on-road measurements of nine gasoline vehicles, seven diesel vehicles, five motorcycles, and four gas evaporation samples. The secondary organic aerosol (SOA) mass yields of gasoline, diesel, motorcycle exhausts, and gas evaporation were estimated based on the mixing ratio of measured C2-C12 VOC species and inferred carbon number distributions. High aromatic contents were measured in gasoline exhausts and contributed comparatively more SOA yield. A vehicular emission inventory was compiled based on a local survey of on-road traffic in Shanghai and real-world measurements of vehicle emission factors from previous studies in the cities of China. The inventory-based vehicular organic aerosol (OA) productions to total CO emissions were compared with the observed OA to CO concentrations (ΔOA / ΔCO) in the urban atmosphere. The results indicate that vehicles dominate the primary organic aerosol (POA) emissions and OA production, which contributed about 40 and 60 % of OA mass in the urban atmosphere of Shanghai. Diesel vehicles, which accounted for less than 20 % of vehicle kilometers of travel (VKT), contribute more than 90 % of vehicular POA emissions and 80-90 % of OA mass derived by vehicles in urban Shanghai. Gasoline exhaust could be an important source of SOA formation. Tightening the limit of aromatic content in gasoline fuel will be helpful to reduce its SOA contribution. Intermediate-volatile organic compounds (IVOCs) in vehicle exhausts greatly contribute to SOA formation in the urban atmosphere of China. However, more experiments need to be conducted to determine the contributions of IVOCs to OA pollution in China.

  13. Characterization of VOC Emissions from Various Components of Dairy Farming and their effect on San Joaquin Valley Air Quality

    Science.gov (United States)

    Yang, M. M.; Meinardi, S.; Krauter, C.; Blake, D.

    2008-12-01

    The San Joaquin Valley Air Basin in Central California is classified by the U.S. Environmental Protection Agency (EPA) as a serious non-attainment area for health-based eight-hour federal ozone (smog) standard (1). In August 2005, the San Joaquin Valley Air Pollution Control District issued a report identifying dairies as a main source of Volatile Organic Compounds (VOCs) and fine particulate matter in the valley (2). Among these compounds, we have found that ethanol, methanol, acetone and acetaldehyde are produced in major quantities throughout the San Joaquin valley as by-products of yeast fermentation of silage and photochemical oxidation. These oxygenates, especially ethanol, play an important role in ozone (O3) formation within the valley. Three different types of sampling protocols were employed in order to determine the degree of enhancement of the four oxygenates in the valley air shed, as well as to determine their sources, emission profiles and emission rates. An assessment of the emissions of these oxygenates in the valley was achieved using data obtained on low altitude flights through the valley and from ground level samples collected thoughout the valley. The photochemical production of ozone was calculated for each of the four oxygenates and approximately one hundred other quantified VOCs. Based on the Maximum Incremental Reactivity (MIR) scale and concentrations of each oxygenate in the atmosphere, as much as 20% of O3 production in the valley is from ethanol and its photochemical by-product acetaldehyde. Our findings suggest that improvement to the valley air quality may be obtained by focusing on instituting new silage containment practices and regulations. 1. Lindberg, J. "Analysis of the San Joaquin Valley 2007 Ozone Plan." State of California Air Resources Board. Final Draft Staff Report. 5/30/2007. 2. Crow, D., executive director/APCO. "Air Pollution Control Officer's Determination of VOC Emisison Factors for Dairies." San Joaquin Valley Air

  14. Quantifying VOC-Reaction Tracers, Ozone Production, and Continuing Aerosol Production Rates in Urban and Far-Downwind Atmospheres

    Science.gov (United States)

    Chatfield, Robert; Ren, X.; Brune, W.; Fried, A.; Schwab, J.

    2008-01-01

    We have found a surprisingly informative decomposition of the complex question of smoggy ozone production (basically, [HO2] in a more locally determined field of [NO]) in the process of linked investigations of modestly smoggy Eastern North America (by NASA aircraft, July 2004) and rather polluted Flushing, NYC (Queens College, July, 2001). In both rural and very polluted situations, we find that a simple contour graph parameterization of the local principal ozone production rate can be estimated using only the variables [NO] and j(sub rads) [HCHO]: Po(O3) = c (j(sub rads) [HCHO])(sup a) [HCHO](sup b). Here j(sub rads) is the photolysis of HCHO to radicals, presumably capturing many harder-UV photolytic processes and the principle ozone production is that due to HO2; mechanisms suggest that ozone production due to RO2 is closely correlated, often suggesting a limited range of different proportionality factors. The method immediately suggests a local interpretation for concepts of VOC limitation and NOx limitation. We believe that the product j(sub rads) [HCHO] guages the oxidation rate of observed VOC mixtures in a way that also provides [HO2] useful for the principle ozone production rate k [HO2] [NO], and indeed, all ozone chemical production. The success of the method suggests that dominant urban primary-HCHO sources may transition to secondary plume-HCHO sources in a convenient way. Are there other, simple, near-terminal oxidized VOC's which help guage ozone production and aerosol particle formation? Regarding particles, we report on, to the extent NASA Research resources allow, on appealing relationships between far-downwind (Atlantic PBL) HCHO and very fine aerosol (including sulfate. Since j(sub rads) [HCHO] provides a time-scale, we may understand distant-plume particle production in a more quantitative manner. Additionally we report on a statistical search in the nearer field for relationships between glyoxals (important near-terminal aromatic and isoprene

  15. A process-based emission model of volatile organic compounds from silage sources on farms

    Science.gov (United States)

    Bonifacio, H. F.; Rotz, C. A.; Hafner, S. D.; Montes, F.; Cohen, M.; Mitloehner, F. M.

    2017-03-01

    Silage on dairy farms can emit large amounts of volatile organic compounds (VOCs), a precursor in the formation of tropospheric ozone. Because of the challenges associated with direct measurements, process-based modeling is another approach for estimating emissions of air pollutants from sources such as those from dairy farms. A process-based model for predicting VOC emissions from silage was developed and incorporated into the Integrated Farm System Model (IFSM, v. 4.3), a whole-farm simulation of crop, dairy, and beef production systems. The performance of the IFSM silage VOC emission model was evaluated using ethanol and methanol emissions measured from conventional silage piles (CSP), silage bags (SB), total mixed rations (TMR), and loose corn silage (LCS) at a commercial dairy farm in central California. With transport coefficients for ethanol refined using experimental data from our previous studies, the model performed well in simulating ethanol emission from CSP, TMR, and LCS; its lower performance for SB could be attributed to possible changes in face conditions of SB after silage removal that are not represented in the current model. For methanol emission, lack of experimental data for refinement likely caused the underprediction for CSP and SB whereas the overprediction observed for TMR can be explained as uncertainty in measurements. Despite these limitations, the model is a valuable tool for comparing silage management options and evaluating their relative effects on the overall performance, economics, and environmental impacts of farm production. As a component of IFSM, the silage VOC emission model was used to simulate a representative dairy farm in central California. The simulation showed most silage VOC emissions were from feed lying in feed lanes and not from the exposed face of silage storages. This suggests that mitigation efforts, particularly in areas prone to ozone non-attainment status, should focus on reducing emissions during feeding. For

  16. Volatilization of low vapor pressure--volatile organic compounds (LVP-VOCs) during three cleaning products-associated activities: Potential contributions to ozone formation.

    Science.gov (United States)

    Shin, Hyeong-Moo; McKone, Thomas E; Bennett, Deborah H

    2016-06-01

    There have been many studies to reduce ozone formation mostly from volatile organic compound (VOC) sources. However, the role of low vapor pressure (LVP)-VOCs from consumer products remains mostly unexplored and unaddressed. This study explores the impact of high production volume LVP-VOCs on ozone formation from three cleaning products-associated activities (dishwashing, clothes washing, and surface cleaning). We develop a model framework to account for the portion available for ozone formation during the use phase and from the down-the-drain disposal. We apply experimental studies that measured emission rates or models that were developed for estimating emission rates of organic compounds during the use phase. Then, the fraction volatilized (fvolatilized) and the fraction disposed down the drain (fdown-the-drain) are multiplied by the portion available for ozone formation for releases to the outdoor air (fO3|volatilized) and down-the-drain (fO3|down-the-drain), respectively. Overall, for chemicals used in three specific cleaning-product uses, fvolatilized is less than 0.6% for all studied LVP-VOCs. Because greater than 99.4% of compounds are disposed of down the drain during the use phase, when combined with fO3|volatilized and fO3|down-the-drain, the portion available for ozone formation from the direct releases to outdoor air and the down-the-drain disposal is less than 0.4% and 0.2%, respectively. The results from this study indicate that the impact of the studied LVP-VOCs on ozone formation is very sensitive to what occurs during the use phase and suggest the need for future research on experimental work at the point of use. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. 77 FR 28375 - Adequacy Status of the Submitted 2008 and 2022 VOC and NOX

    Science.gov (United States)

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Adequacy Status of the Submitted 2008 and 2022 VOC and NOX Motor Vehicle Emissions Budgets for... VOC (tons per NOX (tons per summer day) summer day) Year 2008 MVEBs for the Boston- 17.8 37.2...

  18. 40 CFR 52.2027 - Approval status of Pennsylvania's Generic NOX and VOC RACT Rules.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Approval status of Pennsylvania's Generic NOX and VOC RACT Rules. 52.2027 Section 52.2027 Protection of Environment ENVIRONMENTAL PROTECTION...) Pennsylvania § 52.2027 Approval status of Pennsylvania's Generic NOX and VOC RACT Rules. (a) Effective November...

  19. De intra-Aziatische vaart: Schepen, 'de Aziatische zeeman' en ondergang van de VOC?

    NARCIS (Netherlands)

    van Rossum, M.

    2011-01-01

    Intra-Asiatic trade: ships, 'the Asian sailor' and the demise of the Dutch East India Company? Matthias van Rossum Active involvement in the intra-Asiatic trade was one of the main pillars of the Dutch East India Company (voc). The intra-Asiatic trade of the voc has, therefore, often been assigned a

  20. Cold Temperature Effects on Speciated VOC Emissions from modern GDI Light Duty Truck

    Science.gov (United States)

    Although gasoline direct injection (GDI) vehicles represent nearly half of the light-duty vehicle market share, few studies have reported speciated volatile organic compounds (VOCs) in GDI vehicle exhaust emissions. In this study, speciated VOC emissions were characterized from t...

  1. 40 CFR 60.312 - Standard for volatile organic compounds (VOC).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds (VOC). 60.312 Section 60.312 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Surface Coating of Metal Furniture § 60.312 Standard for volatile organic compounds (VOC). (a) On and...

  2. 40 CFR 60.112 - Standard for volatile organic compounds (VOC).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for volatile organic compounds (VOC). 60.112 Section 60.112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... After June 11, 1973, and Prior to May 19, 1978 § 60.112 Standard for volatile organic compounds (VOC...

  3. Treating VOC-contaminated gases in activated sludge: Mechanistic model to evaluate design and performance

    Energy Technology Data Exchange (ETDEWEB)

    Bielefeldt, A.R.; Stensel, H.D. [Univ. of Washington, Seattle, WA (United States). Dept. of Civil and Environmental Engineering

    1999-09-15

    A mechanistic model based on independently measurable mass transfer and biokinetic parameters was developed to describe the removal of volatile organic compounds (VOCs) contained in air sparged into activated sludge (suspended growth) gas treatment reactor. The critical mass transfer parameters are the VOC mass transfer coefficient (Kla{sub VOC}), VOC Henry`s coefficient (H) and diffusion coefficient in water, gas flow rate per unit reactor area, and liquid depth. The Kla{sub VOC} is equal to the oxygen Kla (Kla{sub 02}) multiplied by the ratio of the VOC to oxygen diffusivity coefficients in water raised to the power n. Depending on the system power intensity, n ranges from 0.5 to 1.0; 1.0 provides a conservative design. Biokinetic parameters of importance include the Monod coefficients, biomass yield and endogenous decay coefficients, and solids retention time (SRT). The model accurately predicted BTEX removal from air diffused into a 2-L, 40-cm deep lab-scale reactor. Based on the model, a 2-m deep gas treatment reactor should provide > 80% gas treatment efficiency for VOCs with H < 0.35, when the reactor is operated at an SRT which maintains the VOC liquid concentration below 0.1 mg/L, with a Kla{sub 02} of 40 h{sup {minus}1} at an air application rate of 55 m{sup 3}/m{sup 2}-h.

  4. Smartphone-based sensing system using ZnO and graphene modified electrodes for VOCs detection.

    Science.gov (United States)

    Liu, Lei; Zhang, Diming; Zhang, Qian; Chen, Xing; Xu, Gang; Lu, Yanli; Liu, Qingjun

    2017-07-15

    Volatile organic compounds (VOCs) detection is in high demand for clinic treatment, environment monitoring, and food quality control. Especially, VOCs from human exhaled breath can serve as significant biomarkers of some diseases, such as lung cancer and diabetes. In this study, a smartphone-based sensing system was developed for real-time VOCs monitoring using alternative current (AC) impedance measurement. The interdigital electrodes modified with zinc oxide (ZnO), graphene, and nitrocellulose were used as sensors to produce impedance responses to VOCs. The responses could be detected by a hand-held device, sent out to a smartphone by Bluetooth, and reported with concentration on an android program of the smartphone. The smartphone-based system was demonstrated to detect acetone at concentrations as low as 1.56ppm, while AC impedance spectroscopy was used to distinguish acetone from other VOCs. Finally, measurements of the exhalations from human being were carried out to obtain the concentration of acetone in exhaled breath before and after exercise. The results proved that the smartphone-based system could be applied on the detection of VOCs in real settings for healthcare diagnosis. Thus, the smartphone-based system for VOCs detection provided a convenient, portable and efficient approach to monitor VOCs in exhaled breath and possibly allowed for early diagnosis of some diseases. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effect of a sudden infant death syndrome risk reduction education program on risk factor compliance and information sources in primarily black urban communities.

    Science.gov (United States)

    Rasinski, Kenneth A; Kuby, Alma; Bzdusek, Stefanie A; Silvestri, Jean M; Weese-Mayer, Debra E

    2003-04-01

    In the US, a higher incidence of sudden infant death syndrome (SIDS) and a slower decline in the incidence of SIDS has been found among blacks when compared with white infants. The continued racial disparity in SIDS is thought to be attributable to lack of compliance with SIDS risk reduction recommendations. To better understand the disparities in SIDS risk reduction behaviors, we sought to study compliance and information sources related to SIDS among primarily black communities in a city with a high SIDS incidence rate before and after a targeted educational campaign. Pre- and post-SIDS Risk Reduction Education Program telephone surveys were performed in targeted Chicago communities with at least 86% blacks. Data collection for Survey 1 was from September 22 to November 4, 1999. Data collection for Survey 2 was from November 17, 2001, to January 12, 2002, 24 months after the aggressive implementation of a comprehensive, ethnically sensitive risk reduction program. Survey 1 analyzed data from 480 mothers with an infant <12 months of age (327 black, 66 white, and 87 Hispanic) and Survey 2 had 472 mothers (305 black, 77 white, and 90 Hispanic). The incidence of nighttime prone sleeping at Survey 1 was 25% among black respondents, 17% in whites, and 12% in Hispanics and decreased (but not significantly) among all groups by Survey 2. Overall, in Survey 2 compared with Survey 1, fewer mothers reported putting their infants on an adult bed, sofa, or cot both during the day and at night, with the biggest change seen in black mothers for daytime naps. Despite the same educational initiative, blacks increased the use of pillows, stuffed toys, and soft bedding in the sleep environment as compared with whites. More mothers in Survey 2 than in Survey 1 said that they noticed their infants sleeping on their back during the newborn hospitalization. Significantly more black and white mothers in Survey 2 compared with Survey 1 reported that a doctor or nurse had told them what

  6. Diagnosing Tibetan pollutant sources via volatile organic compound observations

    Science.gov (United States)

    Li, Hongyan; He, Qiusheng; Song, Qi; Chen, Laiguo; Song, Yongjia; Wang, Yuhang; Lin, Kui; Xu, Zhencheng; Shao, Min

    2017-10-01

    Atmospheric transport of black carbon (BC) from surrounding areas has been shown to impact the Tibetan environment, and clarifying the geographical source and receptor regions is crucial for providing guidance for mitigation actions. In this study, 10 trace volatile organic compounds (VOCs) sampled across Tibet are chosen as proxies to diagnose source regions and related transport of pollutants to Tibet. The levels of these VOCs in Tibet are higher than those in the Arctic and Antarctic regions but much lower than those observed at many remote and background sites in Asia. The highest VOC level is observed in the eastern region, followed by the southern region and the northern region. A positive matrix factorization (PMF) model found that three factors-industry, biomass burning, and traffic-present different spatial distributions, which indicates that different zones of Tibet are influenced by different VOC sources. The average age of the air masses in the northern and eastern regions is estimated to be 3.5 and 2.8 days using the ratio of toluene to benzene, respectively, which indicates the foreign transport of VOC species to those regions. Back-trajectory analyses show that the Afghanistan-Pakistan-Tajikistan region, Indo-Gangetic Plain (IGP), and Meghalaya-Myanmar region could transport industrial VOCs to different zones of Tibet from west to east. The agricultural bases in northern India could transport biomass burning-related VOCs to the middle-northern and eastern zones of Tibet. High traffic along the unique national roads in Tibet is associated with emissions from local sources and neighboring areas. Our study proposes international joint-control efforts and targeted actions to mitigate the climatic changes and effects associated with VOCs in Tibet, which is a climate sensitive region and an important source of global water.

  7. VOC level control by ventilation improvement of Flexography printing room using CFD modeling

    Directory of Open Access Journals (Sweden)

    Kamal Hadad

    2017-08-01

    Full Text Available Using Computational Fluid Dynamics (CFD technique, the dispersion contours and the exposure rate of Flexographic printing workers to VOCs in a printing department is evaluated. Firstly, VOCs distribution is determined in the printing room due to the existing ventilation system. Through next steps, 4 scenarios for lowering VOCs concentration and its exposure rate to workers are analyzed. Concentration distributions of ethylene glycol (MEG as a representative of VOCs are determined for 4 scenarios. The results show that, regarding the existing ventilation, the concentration of MEG at the breathing height is 1×10-5 mg/m3 and it is higher than the standard permissible level. Finally, the findings of this study lead to lowered VOCs concentrations to 13.87×10-9 mg/m3 via changing the ventilation system for the Flexography Printing Room.

  8. On-road emission characteristics of VOCs from diesel trucks in Beijing, China

    Science.gov (United States)

    Yao, Zhiliang; Shen, Xianbao; Ye, Yu; Cao, Xinyue; Jiang, Xi; Zhang, Yingzhi; He, Kebin

    2015-02-01

    This paper is the first in our series of papers aimed at understanding the volatile organic compound (VOC) emissions of vehicles in Beijing by conducting on-board emission measurements. This paper focuses on diesel vehicles. In this work, 18 China III diesel vehicles, including seven light-duty diesel trucks (LDDTs), four medium-duty diesel trucks (MDDTs) and seven heavy-duty diesel trucks (HDDTs), were examined when the vehicles were driven on predesigned fixed test routes in Beijing in China using a portable emissions measurement system (PEMS). Tedlar bag sampling and 2,4-dinitrophenyhydrazine (DNPH) cartridge sampling were used to collect VOC species, and gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) were used to analyze these samples. We obtained the VOC emission factors and relative compositions for diesel trucks of different sizes under different driving patterns. In total, 64 VOC species were quantified in this study, including 25 alkanes, four alkenes, 13 aromatics, 13 carbonyls and nine other compounds. The emission factors of the total VOCs based on mileage traveled for HDDTs were higher than those of LDDTs and MDDTs. Carbonyls, aromatics and alkanes were the dominant VOC species. Carbonyls accounted for 42.7%-69.2% of the total VOCs in the three types of tested diesel trucks. The total VOC emission factors of the tested vehicles that were driven on non-highway routes were 1.5-2.0 times higher than those of the vehicles driven on the highway. As for the OFP calculation results, with increased vehicle size, the ozone formation potential presented an increasing trend. Among the VOC components, carbonyls were the primary contributor to OFP. In addition, the OFPs under non-highway driving cycles were 1.3-1.7 times those under highway driving cycles. The results of this study will be helpful in improving our understanding of VOCs emitted from on-road diesel trucks in China.

  9. Extreme value analyses of VOC exposures and risks: A comparison of RIOPA and NHANES datasets

    Science.gov (United States)

    Su, Feng-Chiao; Jia, Chunrong; Batterman, Stuart

    2015-01-01

    Extreme value theory, which characterizes the behavior of tails of distributions, is potentially well-suited to model exposures and risks of pollutants. In this application, it emphasizes the highest exposures, particularly those that may be high enough to present acute or chronic health risks. The present study examines extreme value distributions of exposures and risks to volatile organic compounds (VOCs). Exposures of 15 different VOCs were measured in the Relationship between Indoor, Outdoor and Personal Air (RIOPA) study, and ten of the same VOCs were measured in the nationally representative National Health and Nutrition Examination Survey (NHANES). Both studies used similar sampling methods and study periods. Using the highest 5 and 10% of measurements, generalized extreme value (GEV), Gumbel and lognormal distributions were fit to each VOC in these two large studies. Health risks were estimated for individual VOCs and three VOC mixtures. Simulated data that matched the three types of distributions were generated and compared to observations to evaluate goodness-of-fit. The tail behavior of exposures, which clearly neither fit normal nor lognormal distributions for most VOCs in RIOPA, was usually best fit by the 3-parameter GEV distribution, and often by the 2-parameter Gumbel distribution. In contrast, lognormal distributions significantly underestimated both the level and likelihood of extrema. Among the RIOPA VOCs, 1,4-dichlorobenzene (1,4-DCB) caused the greatest risks, e.g., for the top 10% extrema, all individuals had risk levels above 10−4, and 13% of them exceeded 10−2. NHANES had considerably higher concentrations of all VOCs with two exceptions, methyl tertiary-butyl ether and 1,4-DCB. Differences between these studies can be explained by sampling design, staging, sample demographics, smoking and occupation. This analysis shows that extreme value distributions can represent peak exposures of VOCs, which clearly are neither normally nor

  10. Test methods and reduction of organic pollutant compound emissions from wood-based building and furniture materials.

    Science.gov (United States)

    Kim, Sumin; Choi, Yoon-Ki; Park, Kyung-Won; Kim, Jeong Tai

    2010-08-01

    This paper reviews different methods for the analysis of formaldehyde and volatile organic compounds (VOCs) from wood-based panel materials for furniture and building interiors and highlights research on reduction of emission from wood-based panels that can adversely affect indoor air quality. In Korea, standard test methods have been developed to determine formaldehyde and VOC emissions from building products, and the Ministry of Environment regulates the use of building materials with pollutant emissions. Desiccator and perforator methods are being used for formaldehyde and the chamber and field and laboratory emission cell (FLEC) methods for VOC and formaldehyde emissions. The VOC analyzer is a suitable pre-test method for application as a total VOC (TVOC) emission test and bake-out is a useful method to reduce TVOC and formaldehyde emissions from furniture materials in indoor environments. Copyright 2010 Elsevier Ltd. All rights reserved.

  11. Você tem fome de quê?

    Directory of Open Access Journals (Sweden)

    Ana Paula Gramacho Varela

    Full Text Available Este estudo objetivou pensar a obesidade à luz da teoria psicanalítica, focalizando-a como uma epidemia atual em ascendência, apesar de carregar uma antiga história. O conceito psicanalítico de pulsão, utilizado por Sigmund Freud, propiciou uma articulação teórica a partir de uma questão específica: "você tem fome de quê?", o que possibilitou um entendimento que vai além do corpo orgânico, entrando em cena o corpo pulsional. Considerando-se a abrangência em torno do conceito de pulsão, o presente estudo expressou apenas uma possibilidade de entender a obesidade, deixando em aberto questões para futuros estudos.

  12. Detection of new VOC compounds with iCRDS

    Science.gov (United States)

    Huang, H.; Leen, J. B.; Gardner, A.; Gupta, M.; Baer, D. S.

    2015-12-01

    The instrument at Los Gatos Research (a member of ABB Inc.) which is based on incoherent cavity ringdown spectroscopy (iCRDS) that operates in the mid-infrared (bands from 860-1060 cm-1 or 970-1280 cm-1) is capable of detecting a broad range of VOCs, in situ, continuously and autonomously, for example, BTEX compounds (benzene, toluene, ethylbenzene, xylene), including differentiation of xylene isomers. Previously, we have demonstrated the measurement of trichloroethylene (TCE) in zero air with a precision of 0.17 ppb (1σ in 4 minutes), and the measurement of tetrachloroethylene (PCE) with a precision of 0.15 ppb (1σ in 4 minutes). Both of these measured precisions exceed the EPA's commercial building action limit, which for TCE is 0.92 ppb (5 µg/m3) and for PCE is 0.29 ppb (2 µg/m3). This ability has been fully demonstrated by the deployment of the instrument to the Superfund site at Moffett Naval Air Station in Mountain View, California where contaminated ground water results in vapor intrusion of TCE and PCE. For two weeks, the instrument operated continuously and autonomously, successfully measuring TCE and PCE concentrations in both the breathing zone and steam tunnel air, in excellent agreement with previous TO-15 data. In this poster, we present laboratory performance data targeting new toxic molecules with the same instrument. We have demonstrated the measurement of trichlorofluolomethane (Freon 11) in zero air with a precision of 1 ppb (3σ at 1075cm-1), and hexafluoropropene in zero air with a precision of about 0.3 ppb (3σ per spectrum). The iCRDS instrument has shown the ability to continuously and autonomously measure sub-ppb levels of toxic VOCs in the lab/field, offering an unprecedented picture of the short term dynamics associated with vapor intrusion and ground water pollution.

  13. Using a source-receptor approach to characterize the volatile organic compounds from control device exhaust in a science park.

    Science.gov (United States)

    Chen, Chi-Fan; Liang, Jeng-Jong

    2013-03-01

    The science parks have helped shape Taiwan as a high-tech island with a good reputation worldwide. But some complaints on air pollution from the science parks have recently risen. To better understand the environmental effects of volatile organic compounds (VOCs) emitted from various high-tech factories in a science park, this study uses a source-receptor approach to characterize the environmental effects of VOCs from control device exhaust in Taichung Science Park. The chemical mass balance model (CMB8.2) of field measurements of 30 stacks and ambient air at nine sites was used to identify the source and relative contribution of ambient VOCs. The exhaust gas of various pollution control devices was also sampled by drawing a stream of the gases from the exhaust duct at its sampling port. The VOC source profile of each control device exhaust was determined using a database of noncharacteristic compounds. Monthly ambient concentrations of 167 VOCs were divided into monsoon datasets to investigate the effect of monsoon conditions on the emission of VOCs in the science park. This study also suggests a method for determining the optimum source profile in source-receptor modeling, and identifies and analyzes the sources of ambient VOCs at nine sites during southwest and northeast monsoons. Results show a direct relationship between the relative contribution of each source and its control device efficiency. The proposed source-receptor approach can characterize the environmental effect of air pollutants from various factories and successfully assess the efficiency of various control devices.

  14. Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools.

    Science.gov (United States)

    Raysoni, Amit U; Stock, Thomas H; Sarnat, Jeremy A; Chavez, Mayra C; Sarnat, Stefanie Ebelt; Montoya, Teresa; Holguin, Fernando; Li, Wen-Whai

    2017-12-01

    A 14-week air quality study, characterizing the indoor and outdoor concentrations of 18 VOCs at four El Paso, Texas elementary schools, was conducted in Spring 2010. Three schools were in an area of high traffic density and the fourth school, considered as a background school, was situated in an area affected minimally by stationary and mobile sources of air pollution. Passive samplers were deployed for monitoring and analyzed by GC/MS. Differences in the concentration profiles of the BTEX species between the high and low traffic density schools confirmed the pre-defined exposure patterns. Toluene was the predominant compound within the BTEX group and the 96-hr average outdoor concentrations varied from 1.16 to 4.25 μg/m 3 across the four schools. Outdoor BTEX species were strongly correlated with each other (0.63 water usage, and deodorizing cakes used in urinal pots were the likely major sources for these high indoor concentrations. Finally, retrospective assessment of average ambient BTEX concentrations over the last twenty years suggest a gradual decrement in this border region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. An experimental parametric study of VOC from flooring systems exposed to alkaline solutions.

    Science.gov (United States)

    Sjöberg, A; Ramnäs, O

    2007-12-01

    This study outlined the influence of a number of parameters affecting the emission rate from one of the largest sources of VOC in the building stock in the Nordic countries. This source is flooring systems of polyvinyl chloride or linoleum attached to a substrate of moisture damaged or insufficiently dried concrete. The secondary emission rate of degradation products was measured, with the Field and Laboratory Emission Cell, on different flooring systems consisting of three different floorings and three adhesives, exposed to three different aqueous solutions in the range of 11-13.1 pH. The conclusion drawn in this study is that the great majority of the secondary emission originates from the floor adhesive. The occurrence of adhesive and the amount of adhesive used have a significant influence on the emission rate. A critical pH value for degradation of the adhesive seems to lie somewhere between 11 and 13 pH. When designing a floor system or a renovation of a damaged flooring system, it is important to bear in mind the influence of parameters that may drastically shorten the service life. Flooring adhesive may decompose in a moist alkaline environment and give rise to unacceptable secondary emission rates.

  16. Gaseous VOCs rapidly modify particulate matter and its biological effects - Part 1: Simple VOCs and model PM

    Science.gov (United States)

    Ebersviller, S.; Lichtveld, K.; Sexton, K. G.; Zavala, J.; Lin, Y.-H.; Jaspers, I.; Jeffries, H. E.

    2012-12-01

    This is the first of a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOC), particulate matter (PM), and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of biological effects, using cultured human lung cells as model indicators. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects) from cells exposed to chamber air relative to cells exposed to clean air. The exposure systems permit virtually gas-only- or PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure. Our simple experiments in this part of the study were designed to eliminate many competing atmospheric processes to reduce ambiguity in our results. Simple volatile and semi-volatile organic gases that have inherent cellular toxic properties were tested individually for biological effect in the dark (at constant humidity). Airborne mixtures were then created with each compound to which we added PM that has no inherent cellular toxic properties for another cellular exposure. Acrolein and p-tolualdehyde were used as model VOCs and mineral oil aerosol (MOA) was selected as a surrogate for organic-containing PM. MOA is appropriately complex in composition to represent ambient PM, and exhibits no inherent cellular toxic effects and thus did not contribute any biological detrimental effects on its own. Chemical measurements, combined with the responses of our biological exposures, clearly demonstrate that gas-phase pollutants can modify the composition of PM (and its resulting detrimental effects on lung cells). We observed that, even if the gas-phase pollutants are not

  17. Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    E. Dunne

    2018-01-01

    Full Text Available Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH–HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography during routine monitoring as part of the Sydney Particle Study (SPS campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75–0.98 and small root mean square of the deviations (RMSD of the observations from the regression line with a median of 0.11 (range 0.04–0.23 ppbv. These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16–2.01. The intercepts varied with a median of 0.04 and a range of −0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for

  18. Comparison of VOC measurements made by PTR-MS, adsorbent tubes-GC-FID-MS and DNPH derivatization-HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

    Science.gov (United States)

    Dunne, Erin; Galbally, Ian E.; Cheng, Min; Selleck, Paul; Molloy, Suzie B.; Lawson, Sarah J.

    2018-01-01

    Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC) measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH-HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography) during routine monitoring as part of the Sydney Particle Study (SPS) campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75-0.98) and small root mean square of the deviations (RMSD) of the observations from the regression line with a median of 0.11 (range 0.04-0.23 ppbv). These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA) regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16-2.01. The intercepts varied with a median of 0.04 and a range of -0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for benzene, toluene and isoprene by

  19. Aberrant promoter methylation in genes related to hematopoietic malignancy in workers exposed to a VOC mixture.

    Science.gov (United States)

    Jiménez-Garza, Octavio; Guo, Liqiong; Byun, Hyang-Min; Carrieri, Mariella; Bartolucci, Giovanni Battista; Barrón-Vivanco, Briscia Socorro; Baccarelli, Andrea A

    2018-01-15

    Occupational exposure to volatile organic compounds (VOCs) may cause hematopoietic malignancy, either by single exposure to benzene or possibly due to a concomitant exposure to several VOCs. Since oxidative stress, inflammation and DNA repair pathways are closely involved in cancer development, the effect of VOC exposure on expression of proteins involved in these pathways has been studied, but epigenetic changes have not been well described. Here, DNA methylation status following occupational exposure to a VOC mixture was assessed by bisulfite sequencing of the promoter regions of seven genes involved in the mentioned pathways. Peripheral blood samples and individual-level VOC exposure data were obtained from healthy leather shoe factory workers (LS, n=40) and gas station attendants (GS, n=36), as well as a reference group of university employees (C, n=66). Exposure levels for acetone, ethylbenzene, methyl ethyl ketone, n-hexane, toluene and xylene were higher in LS (pVOC mixture. These subcellular modifications may represent the initial mechanism of toxicity leading to hematopoietic malignancy, possibly due to a synergistic, hematotoxic effect of VOC mixtures. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Evaluation of Bio-VOC Sampler for Analysis of Volatile Organic Compounds in Exhaled Breath.

    Science.gov (United States)

    Kwak, Jae; Fan, Maomian; Harshman, Sean W; Garrison, Catherine E; Dershem, Victoria L; Phillips, Jeffrey B; Grigsby, Claude C; Ott, Darrin K

    2014-09-29

    Monitoring volatile organic compounds (VOCs) from exhaled breath has been used to determine exposures of humans to chemicals. Prior to analysis of VOCs, breath samples are often collected with canisters or bags and concentrated. The Bio-VOC breath sampler, a commercial sampling device, has been recently introduced to the market with growing use. The main advantage for this sampler is to collect the last portion of exhaled breath, which is more likely to represent the air deep in the lungs. However, information about the Bio-VOC sampler is somewhat limited. Therefore, we have thoroughly evaluated the sampler here. We determined the volume of the breath air collected in the sampler was approximately 88 mL. When sampling was repeated multiple times, with the succeeding exhalations applied to a single sorbent tube, we observed linear relationships between the normalized peak intensity and the number of repeated collections with the sampler in many of the breath VOCs detected. No moisture effect was observed on the Tenax sorbent tubes used. However, due to the limitation in the collection volume, the use of the Bio-VOC sampler is recommended only for detection of VOCs present at high concentrations unless repeated collections of breath samples on the sampler are conducted.

  1. Triple-rule-out dual-source CT angiography of patients with acute chest pain: Dose reduction potential of 100 kV scanning

    Energy Technology Data Exchange (ETDEWEB)

    Krissak, Radko, E-mail: radko.krissak@umm.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Henzler, Thomas; Prechel, Anne; Reichert, Miriam [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Gruettner, Joachim; Sueselbeck, Tim [1st Department of Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany); Schoenberg, Stefan O.; Fink, Christian [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University (Germany)

    2012-12-15

    Purpose: To investigate the dose reduction potential of low kV triple-rule-out dual-source CT angiography (TRO-CTA) in non-obese (BMI ≤ 25 kg/m{sup 2}) patients with acute chest pain. Materials and methods: Sixty consecutive patients were randomly assigned to two different retrospectively ECG-gated TRO-CTA protocols in this prospective trial: Thirty patients were examined with a 120-kV standard protocol (320 reference mAs with automatic tube current modulation, automatically adapted pitch and ECG-pulsing) and served as the control group (group 1), an otherwise identical 100 kV protocol was used in the other thirty patients (group 2) for a radiation dose reduction. Subjective image quality was assessed on a 5 point scale (1: excellent, 5: non-diagnostic) by two blinded observers. Quantitative image analysis assessed vascular attenuation, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in different vascular segments. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSv mGy{sup −1} cm{sup −1}. Results: There was no significant difference of age, BMI, heart rate, pitch or scan length between both patient groups. Subjective image quality was rated similar in both groups (group 1: 1.2 ± 0.4, group 2: average score = 1.3 ± 0.5). Vessel attenuation was significantly higher in group 2 than in group 1 (ascending aorta: 456 ± 83 HU vs. 370 ± 78 HU, p < 0.001; pulmonary artery: 468 ± 118 HU vs. 411 ± 91 HU, p = 0.03; left coronary artery: 437 ± 110 HU vs. 348 ± 89 HU, p < 0.001), however, there was no significant difference in SNR (13.2 ± 7.6 vs. 14.5 ± 7.5, p = 0.49) or CNR (13.8 ± 6.6 vs. 15.9 ± 7.7, p = 0.25). The effective radiation dose of the 100 kV protocol was significantly lower (9.6 ± 3.2 mSv vs. 18.1 ± 9.4 mSv, p < 0.0001). Conclusion: TRO-CTA with 100 kV is feasible in non-obese patients and results in diagnostic image quality and significantly reduced radiation dose.

  2. Emissions of volatile organic compounds (VOCs) from the food and drink industries of the European community

    Science.gov (United States)

    Passant, Neil R.; Richardson, Stephen J.; Swannell, Richard P. J.; Gibson, N.; Woodfield, M. J.; van der Lugt, Jan Pieter; Wolsink, Johan H.; Hesselink, Paul G. M.

    Estimates were made of the amounts of volatile organic compounds (VOCs) released into the atmosphere as a result of the industrial manufacture and processing of food and drink in the European Community. The estimates were based on a review of literature sources, industrial and government contacts and recent measurements. Data were found on seven food manufacturing sectors (baking, vegetable oil extraction, solid fat processing, animal rendering, fish meal processing, coffee production and sugar beet processing) and three drink manufacturing sectors (brewing, spirit production and wine making). The principle of a data quality label is advocated to illustrate the authors' confidence in the data, and to highlight areas for further research. Emissions of ethanol from bread baking and spirit maturation were found to be the principle sources. However, significant losses of hexane and large quantities of an ill-defined mixture of partially oxidized hydrocarbons were noted principally from seed oil extraction and the drying of plant material, respectively. This latter mixture included low molecular weight aldehydes, carboxylic acids, ketones, amines and esters. However, the precise composition of many emissions were found to be poorly understood. The total emission from the food and drink industry in the EC was calculated as 260 kt yr -1. However, many processes within the target industry were found to be completely uncharacterized and therefore not included in the overall estimate (e.g. soft drink manufacture, production of animal food, flavourings, vinegar, tea, crisps and other fried snacks). Moreover, the use of data quality labels illustrated the fact that many of our estimates were based on limited data. Hence, further emissions monitoring is recommended from identified sources (e.g. processing of sugar beet, solid fat and fish meal) and from uncharacterized sources.

  3. Field demonstration and transition of SCAPS direct push VOC in-situ sensing technologies

    Energy Technology Data Exchange (ETDEWEB)

    William M. Davis

    1999-11-03

    This project demonstrated two in-situ volatile organic compound (VOC) samplers in combination with the direct sampling ion trap mass spectrometer (DSITMS). The technologies chosen were the Vadose Sparge and the Membrane Interface Probe (MIP) sensing systems. Tests at two demonstration sites showed the newer VOC technologies capable of providing in situ contaminant measurements at two to four times the rate of the previously demonstrated Hydrosparge sensor. The results of this project provide initial results supporting the utility of these new technologies to provide rapid site characterization of VOC contaminants in the subsurface.

  4. Extended Research on Detection of Deception Using Volatile Organic Compound (VOC) Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Center for Human Reliability Studies

    2006-06-01

    A system that captures and analyzes volatile organic compound (VOC) emissions from skin surfaces may offer a viable alternative method to the polygraph instrument currently in use for detecting deception in U.S. government settings. Like the involuntary autonomic central nervous system response data gathered during polygraph testing, VOC emissions from the skin may provide data that can be used to detect stress caused by deception. Detecting VOCs, then, may present a noninvasive, non-intrusive method for observing, recording, and quantifying evidence of stress or emotional change.

  5. Removal of VOCs from groundwater using membrane-assisted solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hutter, J.C.; Vandegrift, G.F.; Nunez, L.; Redfield, D.H.

    1992-01-01

    A membrane-assisted solvent extraction (MASX) system coupled to a membrane-assisted distillation stripping (MADS) system for use in decontaminating groundwater is discussed. Volatile organic compounds (VOCs) are extracted in the MASX using a sunflower oil solvent. In the MADS, VOCs are stripped from the sunflower oil, and the oil is recycled to the MASX. Thermodynamic data for the sunflower oil-water-VOCs system were experimentally collected. Published membrane-mass transfer results along with these data were used to design the MASX and MADS modules.

  6. Removal of VOCs from groundwater using membrane-assisted solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Hutter, J.C.; Vandegrift, G.F.; Nunez, L.; Redfield, D.H.

    1992-11-01

    A membrane-assisted solvent extraction (MASX) system coupled to a membrane-assisted distillation stripping (MADS) system for use in decontaminating groundwater is discussed. Volatile organic compounds (VOCs) are extracted in the MASX using a sunflower oil solvent. In the MADS, VOCs are stripped from the sunflower oil, and the oil is recycled to the MASX. Thermodynamic data for the sunflower oil-water-VOCs system were experimentally collected. Published membrane-mass transfer results along with these data were used to design the MASX and MADS modules.

  7. Dose reduction in abdominal computed tomography: intraindividual comparison of image quality of full-dose standard and half-dose iterative reconstructions with dual-source computed tomography.

    Science.gov (United States)

    May, Matthias S; Wüst, Wolfgang; Brand, Michael; Stahl, Christian; Allmendinger, Thomas; Schmidt, Bernhard; Uder, Michael; Lell, Michael M

    2011-07-01

    We sought to evaluate the image quality of iterative reconstruction in image space (IRIS) in half-dose (HD) datasets compared with full-dose (FD) and HD filtered back projection (FBP) reconstruction in abdominal computed tomography (CT). To acquire data with FD and HD simultaneously, contrast-enhanced abdominal CT was performed with a dual-source CT system, both tubes operating at 120 kV, 100 ref.mAs, and pitch 0.8. Three different image datasets were reconstructed from the raw data: Standard FD images applying FBP which served as reference, HD images applying FBP and HD images applying IRIS. For the HD data sets, only data from 1 tube detector-system was used. Quantitative image quality analysis was performed by measuring image noise in tissue and air. Qualitative image quality was evaluated according to the European Guidelines on Quality criteria for CT. Additional assessment of artifacts, lesion conspicuity, and edge sharpness was performed. : Image noise in soft tissue was substantially decreased in HD-IRIS (-3.4 HU, -22%) and increased in HD-FBP (+6.2 HU, +39%) images when compared with the reference (mean noise, 15.9 HU). No significant differences between the FD-FBP and HD-IRIS images were found for the visually sharp anatomic reproduction, overall diagnostic acceptability (P = 0.923), lesion conspicuity (P = 0.592), and edge sharpness (P = 0.589), while HD-FBP was rated inferior. Streak artifacts and beam hardening was significantly more prominent in HD-FBP while HD-IRIS images exhibited a slightly different noise pattern. Direct intrapatient comparison of standard FD body protocols and HD-IRIS reconstruction suggest that the latest iterative reconstruction algorithms allow for approximately 50% dose reduction without deterioration of the high image quality necessary for confident diagnosis.

  8. Biodiesel and Cold Temperature Effects on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    Science.gov (United States)

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  9. Biodiesel and Cold Temperature Effect on Speciated Mobile Source Air Toxics from Modern Diesel Trucks

    Science.gov (United States)

    Speciated volatile organic compounds (VOCs) with a particular focus on mobile source air toxics (MSATs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a temperature controlled chass...

  10. Measurements of VOCs in Mexico City during the MILAGRO Campaign

    Science.gov (United States)

    Baker, A. K.; Beyersdorf, A. J.; Blake, N. J.; Meinardi, S.; Atlas, E.; Rowland, F.; Blake, D. R.

    2006-12-01

    During March of 2006 we participated in MILAGRO (Megacities Initiative: Local and Global Research Observations), a multi-platform campaign to measure pollutants in and in outflow from the Mexico City metropolitan area. As part of MILAGRO we collected whole air canister samples at two Mexico City ground sites: the Instituto Mexicano del Petroleo, located in the city, northeast of the center, and the Universidad Technologica de Tecamac, a suburban site approximately 50 km northeast of the city center. Samples were also collected in various other locations throughout Mexico City. Over 300 whole air samples were collected and analyzed for a wide range of volatile organic compounds (VOCs) including methane, carbon monoxide, nonmethane hydrocarbons (NMHCs) and halocarbons. Propane was the most abundant NMHC at both the urban and suburban locations, with mixing ratios frequently in excess of 10 parts per billion at both locations. This is likely the result of the widespread use of liquefied petroleum gas (LPG) of which propane is the major component. For most species, median mixing ratios at the urban sites were significantly greater than at the suburban site. Here we compare results from both urban and suburban locations and also examine the influence of transport on the composition of outflow from Mexico City.

  11. An unheated permeation device for calibrating atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    J. Brito

    2011-10-01

    Full Text Available The development of an unpowered permeation device for continuous calibration of in-situ instruments measuring atmospheric volatile organic compounds (VOCs is described. Being lightweight and compact, and containing only negligible amounts of chemicals, the device is especially suited for field use such as on board aircraft. Its speciality is to maintain the permeation process in thermal equilibrium, so that the instantaneous permeation rate can be ascribed to a simple temperature measurement. This equilibrium state is maintained by a combination of three features: (i a thin PTFE membrane as permeation medium which guarantees short stabilization times, (ii a water bath as heat buffer, and (iii a vacuum-panel based insulation, in which features (ii and (iii minimize temperature drifts to ~30 mK h−1 per Kelvin temperature difference to the environment. The respective uncertainty of the permeation rate due to thermal non-equilibrium is kept below 1%. An extensive theory part details the major permeation processes of gases through porous polymers, being Fick's diffusion, Knudsen flow, and viscous flow. Both the measured stabilization time and the measured temperature dependence of the permeation rate independently indicate that the permeation can be described by a viscous flow model, where diffusion of the gas molecules in large pores (having a diameter of >0.05 μm dominates.

  12. In situ treatment of VOCs by recirculation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Webb, O.F.; Siegrist, R.L.; Ally, M.R.; Sanford, W.E. [Oak Ridge National Lab., TN (United States); Kearl, P.M.; Zutman, J.L. [Oak Ridge National Lab., Grand Junction, CO (United States). Environmental Science Div.

    1994-06-01

    Confronted with contaminated land from the world wars and the postwar industrialization period, German researchers and practicing professionals have worked to develop processes for effective environmental restoration. This presentation documents efforts by Oak Ridge National Laboratory (ORNL) researchers to (1) identify collaborators and German technologies exhibiting near-term potential for clean-up of volatile organic contaminated soil and groundwater at Department of Energy sites, (2) critically assess performance, and (3) inform interested agencies. The project was limited to identification and preliminary evaluation and included engineering computations, groundwater flow modeling, and treatment process modeling. Two processes were identified: (1) the vacuum vaporizer well/groundwater recirculation well and (2) the porous pipe/horizontal well (PP/HW). Both technologies induce a recirculation flow field in the aquifer and enable simultaneous down hole treatment of the aquifer and vadose zone. University of Karlsruhe researchers have demonstrated the UVB/GZB technology in shallow aquifers with moderately high saturated thickness and hydraulic conductivities. The PP/HW technology offers potential for VOC treatment in sites with thin aquifers or heterogeneities. This paper describes identified German technologies and includes critical evaluations of well performance, associated treatment processes, operating variables, and aquifer-well interactions.

  13. A Regenerable VOC Control System (RVCS) for Characterizing Properties of Sorbents Used in Separation Technologies

    Science.gov (United States)

    Nolek, Sara D.; Monje, Oscar A.

    2010-01-01

    This slide presentation reviews the design, method of operation, and testing of a regenerable Volatile Organic Compound (VOC) control system that characterizes properties of sorbents used in separation technologies.

  14. State of California; Mojave Desert AQMD; Proposed Approval of Air Plan Revisions; VOC Emissions

    Science.gov (United States)

    EPA is proposing to approve a revision to the Mojave Desert Air Quality Management District (MDAQMD) portion of the California SIP concerning emissions of volatile organic compounds (VOCs) from marine and pleasure craft coating operations.

  15. Speciated VOC Emissions from an Outdoor Residential Pellet burning Hydronic Heater

    Science.gov (United States)

    Outdoor hydronic heaters used for residential heating emit air pollutants such as particulate matter and volatile organic compounds (VOCs), which can lead to deleterious impacts on local air quality and human health. Detailed speciated emissions measurements are required to accur...

  16. State of California; Sacramento Metropolitan AQMD; Approval of Air Plan Revisions; VOC Emissions

    Science.gov (United States)

    EPA is taking final action to approve a revision to the Sacramento Metropolitan AQMD portion of the California State Implementation Plan (SIP), concerning volatile organic compound (VOC) emissions from Organic Chemical Manufacturing Operations.

  17. Study of VOCs transport and storage in porous media and assemblies

    Science.gov (United States)

    Xu, Jing

    Indoor VOCs concentrations are influenced greatly by the transport and storage of VOCs in building and furnishing materials, majority of which belong to porous media. The transport and storage ability of a porous media for a given VOC can be characterized by its diffusion coefficient and partition coefficient, respectively, and such data are currently lacking. Besides, environmental conditions are another important factor that affects the VOCs emission. The main purposes of this dissertation are: (1) validate the similarity hypothesis between the transport of water vapor and VOCs in porous materials, and help build a database of VOC transport and storage properties with the assistance of the similarity hypothesis; (2) investigate the effect of relative humidity on the diffusion and partition coefficients; (3) develop a numerical multilayer model to simulate the VOCs' emission characteristics in both short and long term. To better understand the similarity and difference between moisture and volatile organic compounds (VOCs) diffusion through porous media, a dynamic dual-chamber experimental system was developed. The diffusion coefficients and partition coefficients of moisture and selected VOCs in materials were compared. Based on the developed similarity theory, the diffusion behavior of each particular VOC in porous media is predictable as long as the similarity coefficient of the VOC is known. Experimental results showed that relative humidity in the 80%RH led to a higher partition coefficient for formaldehyde compared to 50%RH. However, between 25% and 50% RH, there was no significant difference in partition coefficient. The partition coefficient of toluene decreased with the increase of humidity due to competition with water molecules for pore surface area and the non-soluble nature of toluene. The solubility of VOCs was found to correlate well with the partition coefficient of VOCs. The partition coefficient of VOCs was not simply inversely proportional to

  18. VocMat projekt - uudsed e-õppe võimalused turismiasjalistele / Heli Tooman

    Index Scriptorium Estoniae

    Tooman, Heli, 1949-

    2008-01-01

    Turismivaldkonna spetsialistidele mõeldud koolitusprojektist VocMat (Vocational Management Training for the Tourism Industry). Projekti partneriteks Eestis on Ettevõtluse Arendamise Sihtasutuse Turismiarenduskeskus ja Tartu Ülikooli Pärnu kolledzh. Lisa: Kokkuvõte

  19. Use of VOC sensors for air quality control of building ventilation systems

    National Research Council Canada - National Science Library

    M Großklos

    2015-01-01

    .... An air quality control was developed and tested in four single-family passive house dwellings to control the building ventilation system via VOC sensors and a special adaptation algorithm to handle...

  20. SAFARI 2000 Leaf-Level VOC Emissions, Maun, Botswana, Wet Season 2001

    Data.gov (United States)

    National Aeronautics and Space Administration — Biogenic volatile organic compounds (VOCs) comprise a significant proportion of trace gases in the atmospheric environment and play an important role in the...

  1. SAFARI 2000 Leaf-Level VOC Emissions, Maun, Botswana, Wet Season 2001

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Biogenic volatile organic compounds (VOCs) comprise a significant proportion of trace gases in the atmospheric environment and play an important role in...

  2. Impacts of simulated herbivory on VOC emission profiles from coniferous plants

    Science.gov (United States)

    Faiola, C. L.; Jobson, B. T.; VanReken, T. M.

    2014-09-01

    The largest global source of volatile organic compounds (VOCs) in the atmosphere is from biogenic emissions. Plant stressors associated with a changing environment can alter both the quantity and composition of the compounds that are emitted. This study investigated the effects of one global change stressor, increased herbivory, on plant emissions from five different coniferous species: bristlecone pine (Pinus aristata), blue spruce (Picea pungens), western redcedar (Thuja plicata), grand fir (Abies grandis), and Douglas-fir (Pseudotsugas menziesii). Herbivory was simulated in the laboratory via exogenous application of methyl jasmonate, an herbivory proxy. Gas-phase species were measured continuously with a gas chromatograph coupled to a mass spectrometer and flame ionization detector (GC-MS-FID). Stress responses varied between the different plant types and even between experiments using the same set of saplings. The compounds most frequently impacted by the stress treatment were alpha-pinene, beta-pinene, 1,8-cineol, beta-myrcene, terpinolene, limonene, and the cymene isomers. Individual compounds within a single experiment often exhibited a different response to the treatment from one another.

  3. Emissions and photochemistry of oxygenated VOCs in urban plumes in the Northeastern United States

    Directory of Open Access Journals (Sweden)

    R. Sommariva

    2011-07-01

    Full Text Available Photochemical processes inside urban plumes in the Northeast of the United States have been studied using a highly detailed chemical model, based upon the Master Chemical Mechanism (MCM. The model results have been compared to measurements of oxygenated VOCs (acetone, methyl ethyl ketone, acetaldehyde, acetic acid and methanol obtained during several flights of the NOAA WP-3D aircraft, which sampled plumes from the New York City area during the ICARTT campaign in 2004. The agreement between the model and the measurements was within 40–60 % for all species, except acetic acid.

    The model results have been used to study the formation and photochemical evolution of acetone, methyl ethyl ketone and acetaldehyde. Under the conditions encountered during the ICARTT campaign, acetone is produced from the oxidation of propane (24–28 % and i-propanol (<15 % and from a number of products of i-pentane oxidation. Methyl ethyl ketone (MEK is mostly produced from the oxidation of n-butane (20–30 % and 3-methylpentane (<40 %. Acetaldehyde is formed from several precursors, mostly small alkenes, >C5 alkanes, propanal and MEK. Ethane and ethanol oxidation account, respectively, for 6–23 % and 5–25 % of acetaldehyde photochemical formation. The results highlight the importance of alkanes for the photochemical production of ketones and the role of hydroperoxides in sustaining their formation far from the emission sources.

  4. VOC characteristics and inhalation health risks in newly renovated residences in Shanghai, China.

    Science.gov (United States)

    Dai, Haixia; Jing, Shengao; Wang, Hongli; Ma, Yingge; Li, Li; Song, Weimin; Kan, Haidong

    2017-01-15

    Exposure to indoor VOCs is expected to link to a variety of negative health outcome. The popularity of decorations and refurbishment in homes in China has given rise to indoor elevated VOC levels, potentially posing health threats to residents. In this study, concentrations of 101 VOC compounds and associated health risks were investigated in newly renovated homes in Shanghai. The potential excess inhalation health risks from home exposure of 17 health-related VOCs were estimated by the Inhalation Unit Risk (IUR) and Reference Concentration (RfC) proposed by US EPA. Monte Carlo simulation and sensitivity analysis were used to assess the uncertainty associated with the estimates of health risks. The dominant groups by mass concentration were oxygenated VOCs (o-VOCs), aromatics, alkanes and halogenated VOCs (x-VOCs) .12 VOCs with IARC's confirmed or probable carcinogens ratings were detected with a >60% detection frequency in the total samples. The mean concentrations of BTEX (benzene, toluene, m/p-xylene, o-xylene, ethylbenzene) were 2.32μg/m3, 200.13μg/m3, 39.56μg/m3, 32.59μg/m3 and 26.33μg/m3 respectively, generally higher than those in older homes reported in previous studies except benzene. The mean concentration of methylene chloride (47.43μg/m3) and 1,2-dichloroethane (33.83μg/m3) were noticeably higher than the levels reported in previous studies in Hong Kong, Japan and Canada. Whereas the mean concentration of 1,4-dichlorobenzene (5.53μg/m3) were similar to the results of Canadian national survey but lower than those in Japan. The concentrations of 1,2-dichloroethane, 1,4-dichlorobenzene, and methylene chloride, ethylbenzene presented a mean cancer risk at 7.39×10-6, 1.95×10-6, 1.62×10-6, 1.04×10-6 respectively, above the US EPA proposed acceptable risk level of 1×10-6. Sensitivity analyses indicated that the VOC exposure concentration have a greater impact than the IUR values on the risk assessment. This study highlights the characteristics of

  5. Drone-Based VOC Sampling System for Atmospheric Insights in the Amazon

    OpenAIRE

    Wang, Daniel

    2017-01-01

    Produced mainly through natural emission from vegetation (~1015 grams a year), volatile organic compounds (VOCs) in influence climate through their involvement in photochemistry, such as the production of ozone in the presence of NOx and light. Decades of stationary tower-based studies (~10s of meters) and aircraft flights (~10s of kilometers) have revealed extreme heterogeneity in VOC concentrations in time and space. However, the actual variation in forest cover occurs at ~1 km and less, a ...

  6. VOC emissions during outdoor ship painting and health-risk assessment

    Science.gov (United States)

    Malherbe, Laure; Mandin, Corinne

    Painting of ship external surfaces in building or repair shipyards generates significant emissions of volatile organic compounds (VOC) to the atmosphere. Such emissions have not been specifically regulated so far. The purpose of our study is therefore to evaluate the quantities and as far as possible the nature of the emitted VOC, to characterize the dispersion of these chemicals in the atmosphere and to assess the exposure and resulting health risks for surrounding populations. This study is focused on VOC emitted during outdoor work involving use of paints and solvents. VOC emissions are diffuse, since they come from the whole painted surfaces. A methodology for quantifying them is developed and tested, using information provided by ALSTOM—Chantiers de l'Atlantique and data found in paint technical sheets. Its reliability is checked against emission values established by ALSTOM or found in literature. Then, for two particular situations, construction on one hand, repair on the other hand, atmospheric dispersion of total VOC is simulated to assess the long-term impact (characterized by the plume extension and the annual mean concentrations) of these compounds. Finally, a health-risk assessment based on the estimates is carried out to evaluate the risks by inhalation for people living near the site. Considering the presumed composition of paints and the available reference toxicological values, total VOC are entirely assimilated to toluene. In both examples (construction and repair) and in the current state of knowledge, the calculated risk is not of health concern. Several ways for taking this study further are proposed: a more exhaustive collection of data relative to VOC and other substances contained in paints, on-site measurement of VOC in the ambient air, characterization of diffuse emissions related to other activities, such as purging or welding, and other pollutants, like particles.

  7. What effect does VOC sampling time have on derived OH reactivity?

    Directory of Open Access Journals (Sweden)

    H. Sonderfeld

    2016-05-01

    Full Text Available State-of-the-art techniques allow for rapid measurements of total OH reactivity. Unknown sinks of OH and oxidation processes in the atmosphere have been attributed to what has been termed “missing” OH reactivity. Often overlooked are the differences in timescales over which the diverse measurement techniques operate. Volatile organic compounds (VOCs acting as sinks of OH are often measured by gas chromatography (GC methods which provide low-frequency measurements on a timescale of hours, while sampling times are generally only a few minutes. Here, the effect of the sampling time and thus the contribution of unmeasured VOC variability on OH reactivity is investigated. Measurements of VOC mixing ratios by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS conducted during two field campaigns (ClearfLo and PARADE in an urban and a semi-rural environment were used to calculate OH reactivity. VOCs were selected to represent variability for different compound classes. Data were averaged over different time intervals to simulate lower time resolutions and were then compared to the mean hourly OH reactivity. The results show deviations in the range of 1 to 25 %. The observed impact of VOC variability is found to be greater for the semi-rural site.The selected compounds were scaled by the contribution of their compound class to the total OH reactivity from VOCs based on concurrent gas chromatography measurements conducted during the ClearfLo campaign. Prior to being scaled, the variable signal of aromatic compounds results in larger deviations in OH reactivity for short sampling intervals compared to oxygenated VOCs (OVOCs. However, once scaled with their lower share during the ClearfLo campaign, this effect was reduced. No seasonal effect on the OH reactivity distribution across different VOCs was observed at the urban site.

  8. [Estimation of VOC emission from forests in China based on the volume of tree species].

    Science.gov (United States)

    Zhang, Gang-feng; Xie, Shao-dong

    2009-10-15

    Applying the volume data of dominant trees from statistics on the national forest resources, volatile organic compounds (VOC) emissions of each main tree species in China were estimated based on the light-temperature model put forward by Guenther. China's VOC emission inventory for forest was established, and the space-time and age-class distributions of VOC emission were analyzed. The results show that the total VOC emissions from forests in China are 8565.76 Gg, of which isoprene is 5689.38 Gg (66.42%), monoterpenes is 1343.95 Gg (15.69%), and other VOC is 1532.43 Gg (17.89%). VOC emissions have significant species variation. Quercus is the main species responsible for emission, contributing 45.22% of the total, followed by Picea and Pinus massoniana with 6.34% and 5.22%, respectively. Southwest and Northeast China are the major emission regions. In specific, Yunnan, Sichuan, Heilongjiang, Jilin and Shaanxi are the top five provinces producing the most VOC emissions from forests, and their contributions to the total are 15.09%, 12.58%, 10.35%, 7.49% and 7.37%, respectively. Emissions from these five provinces occupy more than half (52.88%) of the national emissions. Besides, VOC emissions show remarkable seasonal variation. Emissions in summer are the largest, accounting for 56.66% of the annual. Forests of different ages have different emission contribution. Half-mature forests play a key role and contribute 38.84% of the total emission from forests.

  9. Methanol and other VOC fluxes from a Danish beech forest during late springtime

    DEFF Research Database (Denmark)

    Schade, Gunnar W.; Solomon, Sheena J.; Dellwik, Ebba

    2011-01-01

    In-canopy mixing ratio gradients and above-canopy fluxes of several volatile organic compounds (VOCs) were measured using a commercial proton transfer reaction mass spectrometer (PTR-MS) in a European beech (Fagus sylvatica) forest in Denmark. Fluxes of methanol were bidirectional: Emission...... results from tropical and pine forest ecosystems in that they did not show this beech ecosystem to be a strong sink for oxygenated VOCs (OVOCs). Instead, their gradients were flat and only small deposition velocities (...

  10. Quantitative assessment of industrial VOC emissions in China: Historical trend, spatial distribution, uncertainties, and projection

    Science.gov (United States)

    Zheng, Chenghang; Shen, Jiali; Zhang, Yongxin; Huang, Weiwei; Zhu, Xinbo; Wu, Xuecheng; Chen, Linghong; Gao, Xiang; Cen, Kefa

    2017-02-01

    The temporal trends of industrial volatile organic compound (VOC) emissions was comprehensively summarized for the 2011 to 2013 period, and the projections for 2020 to 2050 for China were set. The results demonstrate that industrial VOC emissions in China increased from 15.3 Tg in 2011 to 29.4 Tg in 2013 at an annual average growth rate of 38.3%. Guangdong (3.45 Tg), Shandong (2.85 Tg), and Jiangsu (2.62 Tg) were the three largest contributors collectively accounting for 30.4% of the national total emissions in 2013. The top three average industrial VOC emissions per square kilometer were Shanghai (247.2 ton/km2), Tianjin (62.8 ton/km2), and Beijing (38.4 ton/km2), which were 12-80 times of the average level in China. The data from the inventory indicate that the use of VOC-containing products, as well as the production and use of VOCs as raw materials, as well as for storage and transportation contributed 75.4%, 10.3%, 9.1%, and 5.2% of the total emissions, respectively. ArcGIS was used to display the remarkable spatial distribution variation by allocating the emission into 1 km × 1 km grid cells with a population as surrogate indexes. Combined with future economic development and population change, as well as implementation of policy and upgrade of control technologies, three scenarios (scenarios A, B, and C) were set to project industrial VOC emissions for the years 2020, 2030, and 2050, which present the industrial VOC emissions in different scenarios and the potential of reducing emissions. Finally, the result shows that the collaborative control policies considerably influenced industrial VOC emissions.

  11. Multi-label classification of Croatian legal documents using EuroVoc thesaurus

    OpenAIRE

    Šarić, Frane; Dalbelo Bašić, Bojana; Moens, Marie-Francine; Šnajder, Jan

    2014-01-01

    The automatic indexing of legal documents can improve access to legislation. In this paper we describe the work on EuroVoc indexing of Croatian legislative documents. We focus on the machine learning aspect of the problem. First, we describe the manually indexed Croatian legislative documents collection, which we make freely available. Secondly, we describe the multi-label classification experiments on this collection. A challenge of EuroVoc indexing is class sparsity, and we discuss some...

  12. Use of VOC sensors for air quality control of building ventilation systems

    OpenAIRE

    Großklos, M.

    2015-01-01

    Air quality control with VOC (volatile organic compound) sensors in residential buildings could increase user comfort by adapting to the actual contaminant level. Preliminary tests assessed the dynamics of VOC levels in single-family passive houses with a ventilation system. At normal and exceptional usages, sufficient signal variations were measured for air quality control. An air quality control was developed and tested in four single-family passive house dwellings to cont...

  13. VOC species and emission inventory from vehicles and their SOA formation potentials estimation in Shanghai, China

    OpenAIRE

    Huang, C.; Wang, H. L.; Li, L.; Wang, Q.; Lu, Q.; Gouw, J. A.; Zhou, M.; Jing, S. A.; Lu, J.; Chen, C. H.

    2015-01-01

    Volatile organic compound (VOC) species from vehicle exhausts and gas evaporation were investigated by chassis dynamometer and on-road measurements of nine gasoline vehicles, seven diesel vehicles, five motorcycles, and four gas evaporation samples. The secondary organic aerosol (SOA) mass yields of gasoline, diesel, motorcycle exhausts, and gas evaporation were estimated based on the mixing ratio of measured C2–C12 VOC species and inferred carbon number distributions. High aro...

  14. VOC species and emission inventory from vehicles and their SOA formation potentials estimation in Shanghai, China

    OpenAIRE

    C. Huang; H. L. Wang; L. Li; Q. Wang; Q. Lu; J. A. de Gouw; M. Zhou; S. A. Jing; J. Lu; C. H. Chen

    2015-01-01

    VOC species from vehicle exhaust and gas evaporation were investigated by chassis dynamometer and on-road measurements of 9 gasoline vehicles, 7 diesel vehicles, 5 motorcycles, and 4 gas evaporation samples. The SOA mass yields of gasoline, diesel, motorcycle exhausts, and gas evaporation were calculated based on the mixing ratio of individual VOC species. The SOA mass yields of gasoline and motorcycle exhaust were similar to the results of the published smo...

  15. Characterization of Odorous Compounds (VOC and Carbonyl Compounds in the Ambient Air of Yeosu and Gwangyang, Large Industrial Areas of South Korea

    Directory of Open Access Journals (Sweden)

    Young-Kyo Seo

    2014-01-01

    Full Text Available Odorous compounds play an important role in air pollution in industrial areas and the residential areas surrounding them. This study measured the odorous volatile organic compounds (VOC and carbonyl compounds at Yeosu and Gwangyang, two large industrial areas of South Korea, during four seasons of 2008-2009. Along with these two cities, the same odorous compounds were measured at Suncheon, which was selected as a control site. The concentrations of VOC and carbonyl compounds that were listed as odorous air pollutants by the Ministry of Environment of South Korea are discussed. Benzene and formaldehyde were included in the target analytes because of their carcinogenic nature. Most researchers only examined the concentration of odorous compounds in ambient air but the present study evaluated the odor intensity, which is a new parameter that will help better understand the precise odor perceived by people. This paper describes the seasonal variations and spatial distribution of the above-mentioned odorous compounds at the specified sites. Pearson correlation coefficients between the odorous compounds and other air pollutants, such as ozone, CO, SO2, NO2, and PM10, and meteorological conditions, such as temperature and wind speed, provide the source information of odorous VOC and carbonyl compounds.

  16. Characterization of odorous compounds (VOC and carbonyl compounds) in the ambient air of Yeosu and Gwangyang, large industrial areas of South Korea.

    Science.gov (United States)

    Seo, Young-Kyo; Suvarapu, Lakshmi Narayana; Baek, Sung-Ok

    2014-01-01

    Odorous compounds play an important role in air pollution in industrial areas and the residential areas surrounding them. This study measured the odorous volatile organic compounds (VOC) and carbonyl compounds at Yeosu and Gwangyang, two large industrial areas of South Korea, during four seasons of 2008-2009. Along with these two cities, the same odorous compounds were measured at Suncheon, which was selected as a control site. The concentrations of VOC and carbonyl compounds that were listed as odorous air pollutants by the Ministry of Environment of South Korea are discussed. Benzene and formaldehyde were included in the target analytes because of their carcinogenic nature. Most researchers only examined the concentration of odorous compounds in ambient air but the present study evaluated the odor intensity, which is a new parameter that will help better understand the precise odor perceived by people. This paper describes the seasonal variations and spatial distribution of the above-mentioned odorous compounds at the specified sites. Pearson correlation coefficients between the odorous compounds and other air pollutants, such as ozone, CO, SO2, NO2, and PM10, and meteorological conditions, such as temperature and wind speed, provide the source information of odorous VOC and carbonyl compounds.

  17. Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO{sub 2}) in a medium size city in Northern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Parra, M.A. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra. Irunlarrea 1, 31008, Pamplona, Navarra (Spain)], E-mail: mparravi@alumni.unav.es; Elustondo, D.; Bermejo, R.; Santamaria, J.M. [Laboratorio Integrado de Calidad Ambiental (LICA), Departamento de Quimica y Edafologia, Facultad de Ciencias, Universidad de Navarra. Irunlarrea 1, 31008, Pamplona, Navarra (Spain)

    2009-01-15

    Ambient concentrations of volatile organic compounds (VOC) and nitrogen dioxide (NO{sub 2}) were measured by means of passive sampling at 40 sampling points in a medium-size city in Northern Spain, from June 2006 to June 2007. VOC and NO{sub 2} samplers were analysed by thermal desorption followed by gas chromatography/mass-selective detector and by visible spectrophotometry, respectively. Mean concentrations of benzene, toluene, ethylbenzene, xylenes, propylbenzene, trimethylbenzenes, and NO{sub 2} were 2.84, 13.26, 2.15, 6.01, 0.59, 1.32 and 23.17 {mu}g m{sup -3} respectively, and found to be highly correlated. Their spatial distribution showed high differences in small distances and pointed to traffic as the main emission source of these compounds. The lowest levels of VOC and NO{sub 2} occurred during summer, owing to the increase in solar radiation and to lower traffic densities. Mean concentrations of benzene and NO{sub 2} exceeded the European limits at some of the monitored points.

  18. [Development of a membrane inlet-single photon ionization/chemical ionization-mass spectrometer for online analysis of VOCs in water].

    Science.gov (United States)

    Hua, Lei; Wu, Qing-Hao; Hou, Ke-Yong; Cui, Hua-Peng; Chen, Ping; Zhao, Wu-Duo; Xie, Yuan-Yuan; Li, Hai-Yang

    2011-12-01

    A home-made membrane inlet- single photon ionization/chemical ionization- time-of-flight mass spectrometer has been described. A vacuum ultraviolet (VUV) lamp with photon energy of 10.6 eV was used as the light source for single photon ionization (SPI). Chemical ionization (CI) was achieved through ion-molecule reactions with O2- reactant ions generated by photoelectron ionization. The two ionization modes could be rapidly switched by adjusting electric field in the ionization region within 2 s. Membrane inlet system used for rapid enrichment of volatile organic compounds (VOCs) in water was constructed by using a polydimethylsiloxane (PDMS) membrane with a thickness of 50 microm. A purge gas was added to accelerate desorption of analytes from the membrane surface. The purge gas could also help to prevent the pump oil back-streaming into the ionization region from the analyzer chamber and improve the signal to noise ratio (S/N). Achieved detection limits were 2 microg x L(-1) for methyl tert-butyl ether (MTBE) in SPI mode and 1 microg x L(-1) for chloroform in SPI-CI mode within 10 s analysis time, respectively. The instrument has been successfully applied to the rapid analysis of MTBE in simulated underground water nearby petrol station and VOCs in disinfected drinking water. The results indicate that the instrument has a great application prospect for online analysis of VOCs in water.

  19. The AIRMEX study - VOC measurements in public buildings and schools/kindergartens in eleven European cities: Statistical analysis of the data

    Science.gov (United States)

    Geiss, Otmar; Giannopoulos, Georgios; Tirendi, Salvatore; Barrero-Moreno, Josefa; Larsen, Bo R.; Kotzias, Dimitrios

    2011-07-01

    Indoor and outdoor air concentrations as well as personal exposure concentrations of volatile organic compounds (VOCs) have been measured during 2003-2008 in public buildings, schools, kindergartens and private homes in eleven cities over Europe covering geographic areas in north, central and south Europe during different seasons within the frame of the AIRMEX (European Indoor Air Monitoring and Exposure assessment) study. A database is presented containing the results for 23 VOCs based upon approximately 1000 samples taken from 182 different working environments (offices, classrooms, waiting halls) in public buildings, schools and kindergartens, from 103 private homeplaces and from adult volunteers (148 samples). The statistical analysis of the data demonstrated that sources in the indoor environment are prevailing for most of the investigated VOCs with indoor/outdoor (I/O) concentration ratios following the order: hexanal ≈ D-limonene ≫ formaldehyde > acetone > 1-butoxy-2-propanol > acetaldehyde > propanal > 1-butanol > n-undecane > methylcyclohexane > n-dodecane. For aromatic hydrocarbons the main impact was shown to be penetration from outdoor air as indicated by I/O ratios near one and is characterised by significantly higher indoor as well as outdoor concentrations in the south of Europe with respect to the north. For the terpenes, the lowest indoor concentrations were measured during the warm season, which may be explained by higher ventilation rates and reactions with ozone penetrated from outdoor air.

  20. VOC Reactivity and the Ozone Climate Penalty: Modeled Impacts of Updated Aromatic and Monoterpene Chemistry on the Ozone-temperature Connection

    Science.gov (United States)

    Porter, W. C.; Heald, C. L.; Safieddine, S.

    2016-12-01

    Rising temperatures associated with global warming can increase concentrations of tropospheric ozone (O3) in many regions worldwide, a correlation often described as the "ozone climate penalty". This effect is driven by a variety of underlying chemical, physical, and biological mechanisms, including temperature-dependent reaction rates, emissions of volatile organic compounds (VOCs) from trees and other plant life, and correlations with other meteorological variables. While many of the most important O3-producing VOCs, such as isoprene, are represented in typical chemical transport models such as GEOS-Chem, others - including aromatics from fires and human activity and monoterpenes from natural sources - are not always included in gas-phase chemistry. Here we examine the impact of increased VOC reactivity on the ozone climate penalty due to a more comprehensive treatment of aromatics and monoterpenes in the chemical transport model GEOS-Chem, finding regional impacts not only on daily O3 levels themselves, but also on the O3/temperature relationship. While many uncertainties related to the emissions and chemistry of these species remain, the impact of their inclusion on both current simulations and future projections indicates their importance towards the overall goal of more accurately modeled surface O3.

  1. A comparative study of fungal and bacterial biofiltration treating a VOC mixture.

    Science.gov (United States)

    Estrada, José M; Hernández, Sergio; Muñoz, Raúl; Revah, Sergio

    2013-04-15

    Bacterial biofilters usually exhibit a high microbial diversity and robustness, while fungal biofilters have been claimed to better withstand low moisture contents and pH values, and to be more efficient coping with hydrophobic volatile organic compounds (VOCs). However, there are only few systematic evaluations of both biofiltration technologies. The present study compared fungal and bacterial biofiltration for the treatment of a VOC mixture (propanal, methyl isobutyl ketone-MIBK, toluene and hexanol) under the same operating conditions. Overall, fungal biofiltration supported lower elimination capacities than its bacterial counterpart (27.7 ± 8.9 vs 40.2 ± 5.4 gCm(-3) reactor h(-1)), which exhibited a final pressure drop 60% higher than that of the bacterial biofilter due to mycelial growth. The VOC mineralization ratio was also higher in the bacterial bed (≈ 63% vs ≈ 43%). However, the substrate biodegradation preference order was similar for both biofilters (propanal>hexanol>MIBK>toluene) with propanal partially inhibiting the consumption of the rest of the VOCs. Both systems supported an excellent robustness versus 24h VOC starvation episodes. The implementation of a fungal/bacterial coupled system did not significantly improve the VOC removal performance compared to the individual biofilter performances. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Investigation on Using SBS and Active Carbon Filler to Reduce the VOC Emission from Bituminous Materials.

    Science.gov (United States)

    Cui, Peiqiang; Wu, Shaopeng; Li, Fuzhou; Xiao, Yue; Zhang, Honghua

    2014-08-26

    Bituminous materials are playing a vital role in pavement design and the roofing industry because of outstanding properties. Unfortunately, bituminous materials will release volatile organic compounds (VOC), making them non-environmentally friendly. Therefore, technologies that can be used to decrease the VOC emission are urgently required. In this research, the VOC emission and material behaviors were analyzed and compared to investigate the possibility of adding styrene butadiene styrene (SBS) and active carbon filler into bituminous materials to develop environmentally-friendly materials. Thermal gravimetric analysis-mass spectrometry (TG-MS) and ultraviolet-visible spectroscopy testing (UV-Vis) were employed to characterize the VOC emission process. Temperature sweep testing and frequency sweep testing were conducted to evaluate the rheological properties of bituminous materials. Research results indicated that the combined introduction of 4 wt% styrene butadiene styrene (SBS) and 4 wt% active carbon filler cannot only significantly lower the VOC emission speed and amount, but also improve the deformation resistance behavior at a higher temperature. SBS and active carbon filler can be used to reduce the VOC emission form bituminous materials.

  3. Plant volatile organic compounds (VOCs) in ozone (O3) polluted atmospheres: the ecological effects.

    Science.gov (United States)

    Pinto, Delia M; Blande, James D; Souza, Silvia R; Nerg, Anne-Marja; Holopainen, Jarmo K

    2010-01-01

    Tropospheric ozone (O3) is an important secondary air pollutant formed as a result of photochemical reactions between primary pollutants, such as nitrogen oxides (NOx), and volatile organic compounds (VOCs). O3 concentrations in the lower atmosphere (troposphere) are predicted to continue increasing as a result of anthropogenic activity, which will impact strongly on wild and cultivated plants. O3 affects photosynthesis and induces the development of visible foliar injuries, which are the result of genetically controlled programmed cell death. It also activates many plant defense responses, including the emission of phytogenic VOCs. Plant emitted VOCs play a role in many eco-physiological functions. Besides protecting the plant from abiotic stresses (high temperatures and oxidative stress) and biotic stressors (competing plants, micro- and macroorganisms), they drive multitrophic interactions between plants, herbivores and their natural enemies e.g., predators and parasitoids as well as interactions between plants (plant-to-plant communication). In addition, VOCs have an important role in atmospheric chemistry. They are O3 precursors, but at the same time are readily oxidized by O3, thus resulting in a series of new compounds that include secondary organic aerosols (SOAs). Here, we review the effects of O3 on plants and their VOC emissions. We also review the state of current knowledge on the effects of ozone on ecological interactions based on VOC signaling, and propose further research directions.

  4. Harm reduction services as a point-of-entry to and source of end-of-life care and support for homeless and marginally housed persons who use alcohol and/or illicit drugs: a qualitative analysis

    Directory of Open Access Journals (Sweden)

    McNeil Ryan

    2012-05-01

    Full Text Available Abstract Background Homeless and marginally housed persons who use alcohol and/or illicit drugs often have end-of-life care needs that go unmet due to barriers that they face to accessing end-of-life care services. Many homeless and marginally housed persons who use these substances must therefore rely upon alternate sources of end-of-life care and support. This article explores the role of harm reduction services in end-of-life care services delivery to homeless and marginally housed persons who use alcohol and/or illicit drugs. Methods A qualitative case study design was used to explore end-of-life care services delivery to homeless and marginally housed persons in six Canadian cities. A key objective was to explore the role of harm reduction services. 54 health and social services professionals participated in semi-structured qualitative interviews. All participants reported that they provided care and support to this population at end-of-life. Results Harm reduction services (e.g., syringe exchange programs, managed alcohol programs, etc. were identified as a critical point-of-entry to and source of end-of-life care and support for homeless and marginally housed persons who use alcohol and/or illicit drugs. Where possible, harm reduction services facilitated referrals to end-of-life care services for this population. Harm reduction services also provided end-of-life care and support when members of this population were unable or unwilling to access end-of-life care services, thereby improving quality-of-life and increasing self-determination regarding place-of-death. Conclusions While partnerships between harm reduction programs and end-of-life care services are identified as one way to improve access, it is noted that more comprehensive harm reduction services might be needed in end-of-life care settings if they are to engage this underserved population.

  5. A framework for modeling non-steady-state concentrations of semivolatile organic compounds indoors ― I: Emissions from diffusional sources and sorption by interior surfaces

    Science.gov (United States)

    Over the past two decades, more than 20 mass transfer models have been developed for the sources, sinks, and barriers for volatile and semivolatile organic compounds (VOCs and SVOCs) in the indoor environment. While these models have greatly improved our understanding of VOC and ...

  6. Quantification of indoor and outdoor volatile organic compounds (VOCs) in pubs and cafés in Pamplona, Spain

    Science.gov (United States)

    Parra, M. A.; Elustondo, D.; Bermejo, R.; Santamaría, J. M.

    Indoor and outdoor concentrations of volatile organic compounds (VOCs) were measured in 30 pubs and cafés (13 smoking, 13 non-smoking and 4 mixed atmospheres) in Pamplona city, Spain. The samples were obtained using a sampling pocket pump connected to stainless steel tubes filled with Tenax TA, and subsequently analysed by means of GC-MS coupled to a thermal desorption unit. The levels registered were found to be generally higher indoors. Smoking, cleaning products and the entrance of outdoor pollutants were identified as the main sources of these compounds, the later being especially relevant in non-smoking areas. BTEX concentrations were higher during the winter months and higher in smoking areas also.

  7. Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants

    Science.gov (United States)

    Bracho-Nunez, A.; Knothe, N. M.; Welter, S.; Staudt, M.; Costa, W. R.; Liberato, M. A. R.; Piedade, M. T. F.; Kesselmeier, J.

    2012-11-01

    As volatile organic compounds (VOCs) significantly affect atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects), emission inventories defining regional and global biogenic VOC emission strengths are important. The aim of this work was to achieve a description of VOC emissions from poorly described tropical vegetation to be compared with the quite well investigated and highly heterogeneous emissions from Mediterranean vegetation. For this task, common plant species of both ecosystems were investigated. Sixteen plant species from the Mediterranean area, which is known for its special diversity in VOC emitting plant species, were chosen. In contrast, little information is currently available regarding emissions of VOCs from tropical tree species at the leaf level. Twelve plant species from different environments of the Amazon basin, i.e. Terra firme, Várzea and Igapó, were screened for emission of VOCs at leaf level with a branch enclosure system. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was quantitatively the most dominant compound emitted followed by monoterpenes, methanol and acetone. Most of the Mediterranean species emitted a variety of monoterpenes, whereas only five tropical species were monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene > limonene > sabinene > β-pinene). Mediterranean plants showed additional emissions of sesquiterpenes, whereas in the case of plants from the Amazon region no sesquiterpenes were detected probably due to a lack of sensitivity in the measuring systems. On the other hand methanol emissions, an indicator of growth, were common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed heterogeneous emissions

  8. Characterisation and treatment of VOCs in process water from upgrading facilities for compressed biogas (CBG).

    Science.gov (United States)

    Nilsson Påledal, S; Arrhenius, K; Moestedt, J; Engelbrektsson, J; Stensen, K

    2016-02-01

    Compression and upgrading of biogas to vehicle fuel generates process water, which to varying degrees contains volatile organic compounds (VOCs) originating from the biogas. The compostion of this process water has not yet been studied and scientifically published and there is currently an uncertainty regarding content of VOCs and how the process water should be managed to minimise the impact on health and the environment. The aim of the study was to give an overview about general levels of VOCs in the process water. Characterisation of process water from amine and water scrubbers at plants digesting waste, sewage sludge or agricultural residues showed that both the average concentration and composition of particular VOCs varied depending on the substrate used at the biogas plant, but the divergence was high and the differences for total concentrations from the different substrate groups were only significant for samples from plants using waste compared to residues from agriculture. The characterisation also showed that the content of VOCs varied greatly between different sampling points for same main substrate and between sampling occasions at the same sampling point, indicating that site-specific conditions are important for the results which also indicates that a number of analyses at different times are required in order to make an more exact characterisation with low uncertainty. Inhibition of VOCs in the anaerobic digestion (AD) process was studied in biomethane potential tests, but no inhibition was observed during addition of synthetic process water at concentrations of 11.6 mg and 238 mg VOC/L. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Peat moss-derived biochars as effective sorbents for VOCs' removal in groundwater.

    Science.gov (United States)

    Kim, Jeonggwan; Lee, Sang Soo; Khim, Jeehyeong

    2017-08-05

    Peat moss-derived biochars were produced at the pyrolytic temperatures of 300, 500, and 700 °C and were tested for evaluating the removal efficiency of volatile organic compounds (VOCs) from waters. As the pyrolytic temperature increases, the carbon contents were increased from 66 to 84%, and the contents of hydrogen and oxygen were decreased from 4 to 1% and from 19 to 4%, respectively. The surface areas of the biochars were 2 m2 g-1 at the pyrolysis temperature of 300 °C and were increased to 200 and 300 m2 g-1 at 500 and 700 °C, respectively. Results of FTIR analysis showed that functional groups such as hydroxyl, nitro, and carboxyl groups were observed in the biochar produced at 300 °C; however, the functional groups were removed in the biochars produced at higher temperatures. Sorption kinetics and equilibrium experiments were conducted with selected six VOCs of benzene (BZN), toluene (TOL), ethylbenzene (EBZ), p-xylene (pXYL), trichloroethylene (TCE), and tetrachloroethylene (PCE), which are the most common VOCs found in contaminated groundwater of South Korea. Sorption equilibrium was attained in 6 h with the constants of first order kinetic rate of 0.5 h-1 for the VOCs tested. Freundlich isotherm well described the adsorption of VOCs to the biochars. Biochar produced at 500 °C showed the highest sorption capacity for all VOCs with an average K f of 7692 (±2265), although biochars produced at 300 °C (K f  = 3146 ± 629) and 700 °C (K f  = 2776 ± 2693) showed the similar sorption capacity. The biochars produced at 500 °C can be an excellent remover of VOCs in contaminated groundwater.

  10. Pollution characteristics of ambient volatile organic compounds (VOCs) in the southeast coastal cities of China.

    Science.gov (United States)

    Tong, Lei; Liao, Xu; Chen, Jinsheng; Xiao, Hang; Xu, Lingling; Zhang, Fuwang; Niu, Zhenchuan; Yu, Jianshuan

    2013-04-01

    With the rapid urbanization, the southeast coastal cities of China are facing increasing air pollution in the past decades. Large emissions of VOCs from vehicles and petrochemical factories have contributed greatly to the local air quality deterioration. Investigating the pollution characteristics of VOCs is of great significance to the environmental risk assessment and air quality improvement. Ambient VOC samples were collected simultaneously from nine coastal cities of southeast China using the Tedlar bags, and were subsequently preprocessed and analyzed using a cryogenic preconcentrator and a gas chromatography-mass spectrometry system, respectively. VOC compositions, spatial distributions, seasonal variations and ozone formation potentials (OPFs) were discussed. Results showed that methylene chloride, toluene, isopropyl alcohol and n-hexane were most abundant species, and oxygenated compounds, aromatics and halogenated hydrocarbons were most abundant chemical classes (62.5-95.6% of TVOCs). Both industrial and vehicular exhausts might contribute greatly to the VOC emissions. The VOC levels in the southeast coastal cities of China were sufficiently high (e.g., 6.5 μg m(-3) for benzene) to pose a health risk to local people. A more serious pollution state was found in the southern cities of the study region, while higher VOC levels were usually observed in winter. The B/T ratio (0.26 ± 0.09) was lower than the typical ratio (ca. 0.6) for roadside samples, while the B/E (1.6-7.6) and T/E (7.2-26.8) ratios were higher than other cities around the world, which indicated a unique emission profile in the study region. Besides, analysis on ozone formation potentials (OFPs) indicated that toluene was the most important species in ozone production with the accountabilities for total OFPs of 22.6 to 59.6%.

  11. Solving widespread low-concentration VOC air pollution problems: Gas-phase photocatalytic oxidation answers the needs of many small businesses

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, C; Turchi, C; Gratson, D

    1995-04-01

    Many small businesses are facing new regulations under the 1990 Amendments to the Clean Air Act. Regulators, as well as the businesses themselves, face new challenges to control small point-source air pollution emissions. An individual business-such as a dry cleaner, auto repair shop, bakery, coffee roaster, photo print shop, or chemical company-may be an insignificant source of air pollution, but collectively, the industry becomes a noticeable source. Often the businesses are not equipped to respond to new regulatory requirements because of limited resources, experience, and expertise. Also, existing control strategies may be inappropriate for these businesses, having been developed for major industries with high volumes, high pollutant concentrations, and substantial corporate resources. Gas-phase photocatalytic oxidation (PCO) is an option for eliminating low-concentration, low-flow-rate emissions of volatile organic compounds (VOCs) from small business point sources. The advantages PCO has over other treatment techniques are presented in this paper. This paper also describes how PCO can be applied to specific air pollution problems. We present our methodology for identifying pollution problems for which PCO is applicable and for reaching the technology`s potential end users. PCO is compared to other gas-phase VOC control technologies.

  12. Emission of volatile organic compounds from silage: Compounds, sources, and implications

    Science.gov (United States)

    Hafner, Sasha D.; Howard, Cody; Muck, Richard E.; Franco, Roberta B.; Montes, Felipe; Green, Peter G.; Mitloehner, Frank; Trabue, Steven L.; Rotz, C. Alan

    2013-10-01

    Silage, fermented cattle feed, has recently been identified as a significant source of volatile organic compounds (VOCs) to the atmosphere. A small number of studies have measured VOC emission from silage, but not enough is known about the processes involved to accurately quantify emission rates and identify practices that could reduce emissions. Through a literature review, we have focused on identifying the most important compounds emitted from corn silage (the most common type of silage in the US) and the sources of these compounds by quantifying their production and emission potential in silage and describing production pathways. We reviewed measurements of VOC emission from silage and assessed the importance of individual silage VOCs through a quantitative analysis of VOC concentrations within silage. Measurements of VOC emission from silage and VOCs present within silage indicated that alcohols generally make the largest contribution to emission from corn silage, in terms of mass emitted and potential ozone formation. Ethanol is the dominant alcohol in corn silage; excluding acids, it makes up more than half of the mean mass of VOCs present. Acids, primarily acetic acid, may be important when emission is high and all VOCs are nearly depleted by emission. Aldehydes and esters, which are more volatile than acids and alcohols, are important when exposure is short, limiting emission of more abundant but less volatile compounds. Variability in silage VOC concentrations is very high; for most alcohols and acids, tolerance intervals indicate that 25% of silages have concentrations a factor of two away from median values, and possibly much further. This observation suggests that management practices can significantly influence VOC concentrations. Variability also makes prediction of emissions difficult. The most important acids, alcohols, and aldehydes present in silage are probably produced by bacteria (and, in the case of ethanol, yeasts) during fermentation and

  13. Soil and groundwater VOCs contamination: How can electrical geophysical measurements help assess post-bioremediation state?

    Science.gov (United States)

    Kessouri, P.; Johnson, T. C.; Day-Lewis, F. D.; Slater, L. D.; Ntarlagiannis, D.; Johnson, C. D.

    2016-12-01

    The former Brandywine MD (Maryland, USA) Defense Reutilization and Marketing Office (DRMO) was designated a hazardous waste Superfund site in 1999. The site was used as a storage area for waste and excess government equipment generated by several U.S. Navy and U.S. Air Force installations, leading to soil and groundwater contamination by volatile organic compounds (VOCs). Active bioremediation through anaerobic reductive dehalogenation was used to treat the groundwater and the aquifer unconsolidated materials in 2008, with electrical geophysical measurements employed to track amendment injections. Eight years later, we used spectral induced polarization (SIP) and time domain induced polarization (TDIP) on 2D surface lines and borehole electrical arrays to assess the long term impact of active remediation on physicochemical properties of the subsurface. Within the aquifer, the treated zone is more electrically conductive, and the phase shift describing the polarization effects is higher than in the untreated zone. Bulk conductivity and phase shift are also locally elevated close to the treatment injection well, possibly due to biogeochemical transformations associated with prolonged bacterial activity. Observed SIP variations could be explained by the presence of biofilms coating the pore space and/or by-products of the chemical reactions catalyzed by the bacterial activity (e.g. iron sulfide precipitation). To investigate these possibilities, we conducted complementary well logging measurements (magnetic susceptibility [MS], nuclear magnetic resonance [NMR], gamma-ray) using 5 boreholes installed at both treated and untreated locations of the site. We also collected water and soil samples on which we conducted microbiological and chemical analyses, along with geophysical observations (SIP, MS and NMR), in the laboratory. These measurements provide further insights into the physicochemical transformations in the subsurface resulting from the treatment and highlight

  14. Work Truck Idling Reduction

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-03-01

    Hybrid utility trucks, with auxiliary power sources for on-board equipment, significantly reduce unnecessary idling resulting in fuel costs savings, less engine wear, and reduction in noise and emissions.

  15. Enhanced removal of VOCs from aquifers during air sparging using thickeners and surfactants: Bench-scale experiments.

    Science.gov (United States)

    Kim, Heonki; Ahn, Dayoung; Annable, Michael D

    2016-01-01

    The effects of controlled air flow paths during air sparging on the removal of volatile organic compounds were examined in this study using a two-dimensional bench-scale physical model. An aqueous solution of sodium carboxymethylcellulose (SCMC), which is a thickener, was used to increase the resistance of water to displacement by injected air in a region around the targeted zone. At the same time, an aqueous solution of sodium dodecylbenzene sulfonate (SDBS), which is a surfactant, was used to reduce the air entry pressure to enhance the air flow through the targeted region. Trichloroethene (TCE), dissolved in water, was used to represent an aqueous phase volatile organic compound (VOC). A binary mixture of perchloroethene (PCE) and n-hexane was also used as a nonaqeous phase liquid (NAPL). Controlled air flow through the source zone, achieved by emplacing a high viscosity aqueous solution into a region surrounding the TCE-impacted zone, resulted in increased TCE removal from 23.0% (control) to 38.2% during a 2.5h period. When the air flow was focused on the targeted source zone of aqueous phase TCE (by decreasing the surface tension within the source zone and its vicinity by 28 dyn/cm, no SCMC applied), the mass removal of TCE was enhanced to 41.3% during the same time period. With SCMC and SDBS applied simultaneously around and beneath a NAPL source zone, respectively, the NAPL components were found to be removed more effectively over a period of 8.2h than the sparging experiment with no additives applied; 84.6% of PCE and 94.0% of n-hexane were removed for the controlled air flow path experiments (with both SCMC and SDBS applied) compared to 52.7% (PCE) and 74.0% (n-hexane) removal for the control experiment (no additives applied). Based on the experimental observations made in this study, applying a viscous aqueous solution around the source zone and a surfactant solution in and near the source zone, the air flow was focused through the targeted contaminant

  16. Volatile Organic Compound (VOC) Emissions from Dairy Cows and Their Waste

    Science.gov (United States)

    Shaw, S.; Holzinger, R.; Mitloehner, F.; Goldstein, A.

    2005-12-01

    Biogenic VOCs are typically defined as those directly emitted from plants, but approximately 6% of global net primary production is consumed by cattle that carry out enteric fermentation and then emit VOCs that could also be considered biogenic. Current regulatory estimates suggest that dairy cattle in central California emit VOCs at rates comparable to those from passenger vehicles in the region, and thus contribute significantly to the extreme non-attainment of ozone standards there. We report PTR-MS measurements of ammonia and VOCs, and cavity-enhanced-absorption gas analyzer (Los Gatos Research, Inc.) measurements of CH4, emitted from dairy cattle in various stages of pregnancy/lactation and their waste. Experiments were conducted in chambers at UC Davis that simulate freestall cow housing conditions. CH4 fluxes ranged from 125-374 lb/cow/year. The compounds with the highest fluxes from '3 cows+waste' treatments were: ammonia (1-18), methanol (0-2.3), acetone+propanal (0.2-0.7), dimethylsulfide (0-0.4), and mass 109 (likely ID = p-cresol; 0-0.3) in lb/cow/year. Mass 60 (likely ID = trimethylamine) and acetic acid were also abundant. There were 10s of additional compounds with detectable, but small, emissions. A few compounds that were likely emitted (i.e. ethanol, formaldehyde, and dimethylamine) were not quantified by the PTR-MS. The total flux for all measured organic gases (TOG = CH4 + PTR-MS VOCs(including acetone+propanal)) averaged 246±45 lb/cow/year for '3 cows+waste' treatments, and was dominated by methane (>98%). TOG flux for 'waste only' treatments averaged 1.1±0.1 lb/cow/year, and was instead dominated by VOC (>84%). The PTR-MS VOCs as a percent of TOG (0.6±0.2%) emitted from '3 cows+waste' treatments in chamber conditions was a factor of 10 smaller than that currently estimated by the California Air Resources Board. In addition, the ozone forming potentials of the most abundant VOCs are only about 10% those of typical combustion or plant

  17. Biomass burning contribution to ambient volatile organic compounds (VOCs) in the Chengdu-Chongqing Region (CCR), China

    Science.gov (United States)

    Li, Lingyu; Chen, Yuan; Zeng, Limin; Shao, Min; Xie, Shaodong; Chen, Wentai; Lu, Sihua; Wu, Yusheng; Cao, Wei

    2014-12-01

    Ambient volatile organic compounds (VOCs) were measured intensively using an online gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID) at Ziyang in the Chengdu-Chongqing Region (CCR) from 6 December 2012 to 4 January 2013. Alkanes contributed the most (59%) to mixing ratios of measured non-methane hydrocarbons (NMHCs), while aromatics contributed the least (7%). Methanol was the most abundant oxygenated VOC (OVOC), contributing 42% to the total amount of OVOCs. Significantly elevated VOC levels occurred during three pollution events, but the chemical composition of VOCs did not differ between polluted and clean days. The OH loss rates of VOCs were calculated to estimate their chemical reactivity. Alkenes played a predominant role in VOC reactivity, among which ethylene and propene were the largest contributors; the contributions of formaldehyde and acetaldehyde were also considerable. Biomass burning had a significant influence on ambient VOCs during our study. We chose acetonitrile as a tracer and used enhancement ratio to estimate the contribution of biomass burning to ambient VOCs. Biomass burning contributed 9.4%-36.8% to the mixing ratios of selected VOC species, and contributed most (>30% each) to aromatics, formaldehyde, and acetaldehyde.

  18. A high sensitivity and wide dynamic range fiber-optic sensor for low-concentration VOC gas detection.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2014-12-05

    In this paper, we propose a volatile organic compound (VOC) gas sensing system with high sensitivity and a wide dynamic range that is based on the principle of the heterodyne frequency modulation method. According to this method, the time period of the sensing signal shift when Nile Red containing a VOC-sensitive membrane of a fiber-optic sensing element comes into contact with a VOC. This sensing membrane produces strong, fast and reversible signals when exposed to VOC gases. The response and recovery times of the proposed sensing system were less than 35 s, and good reproducibility and accuracy were obtained.

  19. A High Sensitivity and Wide Dynamic Range Fiber-Optic Sensor for Low-Concentration VOC Gas Detection

    Directory of Open Access Journals (Sweden)

    Md. Rajibur Rahaman Khan

    2014-12-01

    Full Text Available In this paper, we propose a volatile organic compound (VOC gas sensing system with high sensitivity and a wide dynamic range that is based on the principle of the heterodyne frequency modulation method. According to this method, the time period of the sensing signal shift when Nile Red containing a VOC-sensitive membrane of a fiber-optic sensing element comes into contact with a VOC. This sensing membrane produces strong, fast and reversible signals when exposed to VOC gases. The response and recovery times of the proposed sensing system were less than 35 s, and good reproducibility and accuracy were obtained.

  20. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation

    Science.gov (United States)

    Xiong, Jianyin; Yang, Tao; Tan, Jianwei; Li, Lan; Ge, Yunshan

    2015-01-01

    The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca) and temperature (T), which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C) were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630–2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks. PMID:26452146

  1. Adsorptive performance of chromium-containing ordered mesoporous silica on volatile organic compounds (VOCs

    Directory of Open Access Journals (Sweden)

    Jianwei Fan

    2017-09-01

    Full Text Available Volatile organic compounds (VOCs are the primary poisonous emissions into the atmosphere in natural gas exploitation and disposing process. The adsorption method has been widely applied in actual production because of its good features such as low cost, low energy consumption, flexible devices needed, etc. The commonly used adsorbents like activated carbon, silicon molecular sieves and so on are not only susceptible to plugging or spontaneous combustion but difficult to be recycled. In view of this, a new adsorbent (CrSBA15 was made by the co-assembly method to synthesize the ordered mesoporous silica materials with different amounts of chromium to eliminate VOCs. This new adsorbent was characterized by small-angle-X-ray scattering (SAXS, nitrogen adsorption/desorption, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Its adsorption performance to eliminate VOCs (toluene, benzene, cyclohexane and ethyl acetate used as typical pollutants was also tested systematically. Research results indicate that this new adsorbent of CrSBA-15(30, with the silicon/chromium ration being 30, owns the maximum micropore volume, and shows a higher adsorption performance in eliminating toluene, benzene, cyclohexane and ethyl acetate. Besides, it is cost-effective and much easier to be recycled than the activated carbon. In conclusion, CrSBA-15(30 is a good adsorbent to eliminate VOCs with broad application prospects. Keywords: Mesoporous materials, Silicon dioxide, Synthesis, Adsorption, Volatile organic compounds (VOCs, Recyclability, Energy saving

  2. Fingerprinting oils in water via their dissolved VOC pattern using mid-infrared sensors.

    Science.gov (United States)

    Schädle, Thomas; Pejcic, Bobby; Myers, Matthew; Mizaikoff, Boris

    2014-10-07

    An infrared attenuated total reflection (IR-ATR) method for detecting, differentiating, and quantifying hydrocarbons dissolved in water relevant for oil spills by evaluating the "fingerprint" of the volatile organic compounds (VOCs) associated with individual oil types in the mid-infrared spectral range (i.e., 800-600 cm(-1)) is presented. In this spectral regime, these hydrocarbons provide distinctive absorption features, which may be used to identify specific hydrocarbon patterns that are characteristic for different crude and refined oils. For analyzing the "VOC fingerprint" resulting from various oil samples, aqueous solutions containing the dissolved hydrocarbons from different crude oils (i.e., types "Barrow", "Goodwyn", and "Saladin") and refined oils (i.e., "Petrol" and "Diesel") were analyzed using a ZnSe ATR waveguide as the optical sensing element. To minimize interferences from the surrounding water matrix and for amplifying the VOC signatures by enrichment, a thin layer of poly(ethylene-co-propylene) was coated onto the ATR waveguide surface, thereby enabling the establishment of suitable calibration functions for the quantification of characteristic concentration patterns of the detected VOCs. Multivariate data analysis was then used for a prelininary classification of various oil-types via their VOC patterns.

  3. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation.

    Science.gov (United States)

    Xiong, Jianyin; Yang, Tao; Tan, Jianwei; Li, Lan; Ge, Yunshan

    2015-01-01

    The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca) and temperature (T), which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C) were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630-2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks.

  4. Characterization of VOC Emission from Materials in Vehicular Environment at Varied Temperatures: Correlation Development and Validation.

    Directory of Open Access Journals (Sweden)

    Jianyin Xiong

    Full Text Available The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca and temperature (T, which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630-2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks.

  5. Identification of abiotic and biotic reductive dechlorination in a chlorinated ethene plume after thermal source remediation by means of isotopic and molecular biology tools

    DEFF Research Database (Denmark)

    Badin, Alice; Broholm, Mette Martina; Jacobsen, Carsten S.

    2016-01-01

    was the predominant chlorinated ethene near the source area prior to thermal treatment. After thermal treatment, cDCE became predominant. The biotic contribution to these changes was supported by the presence of Dehalococcoides sp. DNA (Dhc) and Dhc targeted rRNA close to the source area. In contrast, dual C...... with molecular biology tools to evaluate which biogeochemical processes are taking place in an aquifer contaminated with chlorinated ethenes....

  6. Atmospheric H2S as sulphur source for Brassica oleracea : Consequences for the activity of the enzymes of the assimilatory sulphate reduction pathway

    NARCIS (Netherlands)

    Westerman, S; Stulen, I.; Suter, M; Brunold, C; De Kok, LJ

    Short-term exposure of Brassica oleracea L. (curly kale) to atmospheric H2S levels (0.2-0.8 muL .L-1), which an sufficient to meet the plants sulphur requirement, resulted in a decrease in the activity of adenosine 5'-phosphosulphate reductase (APR) in the shoot. The reduction in APR activity was

  7. Factors associated with sources, transport, and fate of volatile organic compounds and their mixtures in aquifers of the United States

    Science.gov (United States)

    Squillace, P.J.; Moran, M.J.

    2007-01-01

    Factors associated with sources, transport, and fate of volatile organic compounds (VOCs) in groundwater from aquifers throughout the United States were evaluated using statistical methods. Samples were collected from 1631 wells throughout the conterminous United States between 1996 and 2002 as part of the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey. Water samples from wells completed in aquifers used to supply drinking water were analyzed for more than 50 VOCs. Wells were primarily rural domestic water supplies (1184), followed by public water supplies (216); the remaining wells (231) supplied a variety of uses. The median well depth was 50 meters. Age-date information shows that about 60% of the samples had a fraction of water recharged after 1953. Chloroform, toluene, 1,2,4-trimethylbenzene, and perchloroethene were some of the frequently detected VOCs. Concentrations generally were less than 1 ??g/L. Source factors include, in order of importance, general land-use activity, septic/sewer density, and sites where large concentrations of VOCs are potentially released, such as leaking underground storage tanks. About 10% of all samples had VOC mixtures that were associated with concentrated sources; 20% were associated with dispersed sources. Important transport factors included well/screen depth, precipitation/groundwater recharge, air temperature, and various soil characteristics. Dissolved oxygen was strongly associated with VOCs and represents the fate of many VOCs in groundwater. Well type (domestic or public water supply) was also an important explanatory factor. Results of multiple analyses show the importance of (1) accounting for both dispersed and concentrated sources of VOCs, (2) measuring dissolved oxygen when sampling wells to help explain the fate of VOCs, and (3) limiting the type of wells sampled in monitoring networks to avoid unnecessary variance in the data, or controlling for this variance during data analysis.

  8. Urban stress-induced biogenic VOC emissions and SOA-forming potentials in Beijing

    Directory of Open Access Journals (Sweden)

    A. Ghirardo

    2016-03-01

    Full Text Available Trees can significantly impact the urban air chemistry by the uptake and emission of reactive biogenic volatile organic compounds (BVOCs, which are involved in ozone and particle formation. Here we present the emission potentials of "constitutive" (cBVOCs and "stress-induced" BVOCs (sBVOCs from the dominant broadleaf woody plant species in the megacity of Beijing. Based on the municipal tree census and cuvette BVOC measurements on leaf level, we built an inventory of BVOC emissions, and assessed the potential impact of BVOCs on secondary organic aerosol (SOA formation in 2005 and 2010, i.e., before and after realizing the large tree-planting program for the 2008 Olympic Games. We found that sBVOCs, such as fatty acid derivatives, benzenoids, and sesquiterpenes, constituted a significant fraction ( ∼  40 % of the total annual BVOC emissions, and we estimated that the overall annual BVOC budget may have doubled from  ∼  4.8  ×  109 g C year−1 in 2005 to  ∼  10.3  ×  109 g C year−1 in 2010 due to the increase in urban greening, while at the same time the emission of anthropogenic VOCs (AVOCs decreased by 24 %. Based on the BVOC emission assessment, we estimated the biological impact on SOA mass formation potential in Beijing. Constitutive and stress-induced BVOCs might produce similar amounts of secondary aerosol in Beijing. However, the main contributors of SOA-mass formations originated from anthropogenic sources (> 90 %. This study demonstrates the general importance to include sBVOCs when studying BVOC emissions. Although the main problems regarding air quality in Beijing still originate from anthropogenic activities, the present survey suggests that in urban plantation programs, the selection of low-emitting plant species has some potential beneficial effects on urban air quality.

  9. A Review of Photocatalysts Prepared by Sol-Gel Method for VOCs Removal

    Directory of Open Access Journals (Sweden)

    Ting Ke Tseng

    2010-05-01

    Full Text Available The sol-gel process is a wet-chemical technique (chemical solution deposition, which has been widely used in the fields of materials science, ceramic engineering, and especially in the preparation of photocatalysts. Volatile organic compounds (VOCs are prevalent components of indoor air pollution. Among the approaches to remove VOCs from indoor air, photocatalytic oxidation (PCO is regarded as a promising method. This paper is a review of the status of research on the sol-gel method for photocatalyst preparation and for the PCO purification of VOCs. The review and discussion will focus on the preparation and coating of various photocatalysts, operational parameters, and will provide an overview of general PCO models described in the literature.

  10. The weekend effect within and downwind of Sacramento ─ Part 1: Observations of ozone, nitrogen oxides, and VOC reactivity

    Directory of Open Access Journals (Sweden)

    A. H. Goldstein

    2007-10-01

    Full Text Available Day-of-week patterns in human activities can be used to examine the ways in which differences in primary emissions result in changes in the rates of photochemical reactions, and the production of secondary pollutants. Data from twelve California Air Resources Board monitoring sites in Sacramento, CA, and the downwind Mountain Counties air basin are analyzed to reveal day of week patterns in ozone and its precursors in the summers of 1998–2002. Measurements of non-methane hydrocarbons are available for the summers of 2001–2003 at three of these sites and NOx at six of these sites for the full time period. This routine monitoring data is complemented by data sets of ozone and nitrogen oxide concentrations obtained in the summers of 2001 and 2003 at three sites in the region and comprehensive measurements of VOC reactivity at two sites in 2001. Daytime concentrations of nitrogen oxides (NOx≡NO+NO2 are approximately 35% lower on weekends at all the sites, whereas the VOC reactivity changes by less than 10%. All six sites in the Sacramento Valley have higher 8-h maximum average ozone on the weekend and are more likely to exceed the national standard of 85 ppb on the weekend. In contrast, all the sites in the Mountain Counties are less likely to exceed the federal ozone standard on the weekend. Analysis of the day-of-week trends in odd oxygen show that the weekend effect of ozone within Sacramento is strongly influenced by NO sources close to the monitoring sites. This suggests that ozone measurements from monitoring sites close to highways, including two rural locations, may not be representative of the regional abundance, and lead to underestimates of long term exposure for humans and ecosystems.

  11. Effect of the addition of zero valent iron (Fe(0)) on the batch biological sulphate reduction using grass cellulose as carbon source.

    Science.gov (United States)

    Mulopo, Jean; Schaefer, L

    2013-12-01

    Mineral mining generates acidic, saline, metal-rich mine waters, often referred to as acid mine drainage (AMD). Treatment of AMD and recovering saleable products during the treatment process are a necessity since water is, especially in South Africa, a scarce commodity. The aim of the study presented here was to investigate the effect of zero valent iron (Fe(0)) on the biological removal of sulphate from AMD in batch reactors. The performance of the reactors was assessed by means of sulphate reduction, chemical oxygen demand (COD), volatile fatty acid (VFA) utilisation and volatile suspended solids (VSS) concentration. To this end, three batch reactors, A, B and C (volume 2.5 L), were operated similarly with the exception of the addition of grass cuttings and iron filings. Reactors A and B received twice as much grass (100 g) as C (50 g). Reactor A received no iron filings to act as a control, while reactors B and C received 50-g iron filings for the experimental duration. The results showed that Fe(0) appears to provide sustained sulphate removal when sufficient grass substrate is available. In reactors A and C, sulphate removal efficiency was higher when the COD concentration was lower due to utilisation. In reactor B, sulphate removal efficiency was accompanied by an accumulation of COD as hydrogen (H2) provided by the Fe(0) was utilised for sulphate reduction. Furthermore, these results showed the potential of Fe(0) to enhance the participation of microorganisms in sulphate reduction.

  12. Comparison of the decomposition VOC profile during winter and summer in a moist, mid-latitude (Cfb) climate.

    Science.gov (United States)

    Forbes, Shari L; Perrault, Katelynn A; Stefanuto, Pierre-Hugues; Nizio, Katie D; Focant, Jean-François

    2014-01-01

    The investigation of volatile organic compounds (VOCs) associated with decomposition is an emerging field in forensic taphonomy due to their importance in locating human remains using biological detectors such as insects and canines. A consistent decomposition VOC profile has not yet been elucidated due to the intrinsic impact of the environment on the decomposition process in different climatic zones. The study of decomposition VOCs has typically occurred during the warmer months to enable chemical profiling of all decomposition stages. The present study investigated the decomposition VOC profile in air during both warmer and cooler months in a moist, mid-latitude (Cfb) climate as decomposition occurs year-round in this environment. Pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their VOC profile was monitored during the winter and summer months. Corresponding control sites were also monitored to determine the natural VOC profile of the surrounding soil and vegetation. VOC samples were collected onto sorbent tubes and analyzed using comprehensive two-dimensional gas chromatography--time-of-flight mass spectrometry (GC × GC-TOFMS). The summer months were characterized by higher temperatures and solar radiation, greater rainfall accumulation, and comparable humidity when compared to the winter months. The rate of decomposition was faster and the number and abundance of VOCs was proportionally higher in summer. However, a similar trend was observed in winter and summer demonstrating a rapid increase in VOC abundance during active decay with a second increase in abundance occurring later in the decomposition process. Sulfur-containing compounds, alcohols and ketones represented the most abundant classes of compounds in both seasons, although almost all 10 compound classes identified contributed to discriminating the stages of decomposition throughout both seasons. The advantages of GC × GC-TOFMS were demonstrated

  13. Reduction of space charge effects in inductively coupled plasma mass spectrometry using a supplemental electron source inside the skimmer: ion transmission and mass spectral characteristics

    Science.gov (United States)

    Praphairaksit; Houk

    2000-06-01

    An electron source consisting of a heated filament has been added to the skimmer to suppress space charge effects in inductively coupled plasma mass spectrometry (ICPMS). Electrons from this source can reduce the space charge repulsion between the positive ions in the ion beam. As a result, ion transmission efficiency and analyte ion sensitivities are significantly improved across the full mass range. MO+/M+ abundance ratios are not affected, M2+/M+ abundance ratios increase only slightly, and no new background ions are created by this electron injection technique.

  14. VOCs in shallow groundwater in new residential/commercial areas of the United States

    Science.gov (United States)

    Squillace, P.J.; Moran, M.J.; Price, C.V.

    2004-01-01

    The quality of shallow groundwater in urban areas was investigated by sampling 518 monitoring wells between 1996 and 2002 as part of the National Water-Quality Assessment Program of the U.S. Geological Survey. Well networks were installed primarily in new residential/commercial areas less than about 30 years old (17 studies) and in small towns (2 studies) by randomly locating as many as 30 monitoring wells in each study area. The median well depth was 10 m. Based on samples with age-date information, almost all groundwater was recharged after 1950. Samples were analyzed for 53 volatile organic compounds (VOCs). Concentrations ranged from about 0.001 to 1000 ??g/L (median 0.04), with less than 1% of the samples exceeding a Maximum Contamination Level or Drinking Water Advisory established by the U.S. Environmental Protection Agency. Using uncensored concentration data, at least one VOC was detected in 88% of the samples, and at least two VOCs were detected in 69% of the samples. Chloroform, toluene, and perchloroethene were the three most frequently detected VOCs. Dissolved oxygen concentration, estimated recharge index, and land-use were significant variables in logistic regression models that explained the presence of the commonly detected VOCs. Dissolved oxygen concentration was the most important explanatory variable in logistic regression models for 6 of the 14 most frequently detected VOCs. Bromodichloromethane, chloroform, and 1,1,1-trichloroethane had a positive correlation with dissolved oxygen; in contrast, dichloroethane, benzene, and toluene had a negative correlation with dissolved oxygen.

  15. Quantile regression of indoor air concentrations of volatile organic compounds (VOC).

    Science.gov (United States)

    Schlink, Uwe; Thiem, Alexander; Kohajda, Tibor; Richter, Matthias; Strebel, Kathrin

    2010-08-15

    There are many factors determining the concentration of volatile organic compounds (VOCs) in indoor air. On the basis of 601 population-based measurements we develop an explicit exposure model that includes factors, such as renovation, furniture, flat size, smoking, and education level of the occupants. As a novel method for the evaluation of concentrations of indoor air pollutants we use quantile regression, which has the advantages of robustness against non-Gaussian distributions (and outliers) and can adjust for unbalanced frequencies of observations. The applied bi- and multivariate quantile regressions provide (1) the VOC burden that is representative for the population of Leipzig, Germany, and (2) an inter-comparison of the effects of the studied factors and their levels. As a result, we find strong evidence for factors of general impact on most VOC components, such as the season, flooring, the type of the room, and the size of the apartment. Other impact factors are very specific to the VOC components. For example, wooden flooring (parquet) and new furniture increase the concentration of terpenes as well as the modifying factors high education and sampling in the child's room. Smokers ventilate their flats in an extent that in general reduces the VOC concentrations, except for benzene (contained in tobacco smoke), which is still higher in smoking than in non-smoking flats. Very often dampness is associated with an increased VOC burden in indoor air. An investigation of mixtures emphasises a high burden of co-occurring terpenes in very small and very large apartments. Copyright 2009 Elsevier B.V. All rights reserved.

  16. Investigation of speciated VOC in gasoline vehicular exhaust under ECE and EUDC test cycles.

    Science.gov (United States)

    Wang, Jun; Jin, Liangmao; Gao, Junhua; Shi, Jianwu; Zhao, Yanlin; Liu, Shuangxi; Jin, Taosheng; Bai, Zhipeng; Wu, Chang-Yu

    2013-02-15

    The emission factors and compositions of volatile organic compounds (VOC) in exhaust gas from in-use gasoline passenger cars were characterized using a chassis dynamometer. Three passenger cars were tested at the ECE and the EUDC drive cycles to represent both urban and suburban driving scenarios. Exhaust gas was collected in Summa canisters and analyzed by gas chromatography-mass spectrometry (GC-MS). Common gaseous emissions (CH(4), NOx, CO, and CO(2)) were measured by an on-board monitoring system. The VOC emission factors of different cars ranged from 0.10 to 0.25 g km(-1) at the ECE cycle, and 0.01-0.02 g km(-1) at the EUDC cycle. A total of 57 individual VOC were detected in the exhaust gas, and the weight percentages were very consistent among the three cars. Ethylene (11.80 wt.%), toluene (11.27 wt.%), and benzene (8.83 wt.%) were the most abundant VOC in exhaust gas. Aromatics (38.32%) dominated the low speed conditions (ECE), while alkanes (37.34%) were the major compounds at the high speed condition (EUDC). The total amount of alkenes did not change much between those two cycles, while ethylene is abundant in the ECE and EUDC cycles. Ozone formation potential (OFP) was calculated to estimate the ozone yield from VOC emissions by gasoline cars and the results showed that OFP of VOC emission at the ECE cycle was about ten times higher than that at the EUDC cycle. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. On-road emission characteristics of VOCs from light-duty gasoline vehicles in Beijing, China

    Science.gov (United States)

    Cao, Xinyue; Yao, Zhiliang; Shen, Xianbao; Ye, Yu; Jiang, Xi

    2016-01-01

    This study is the third in a series of three papers aimed at characterizing the VOC emissions of vehicles in Beijing. In this study, 30 light-duty vehicles fueled with gasoline were evaluated using a portable emission measurement system (PEMS) as they were driven on a predesigned, fixed test route. All of the tested vehicles were rented from private vehicle owners and spanned regulatory compliance guidelines ranging from Pre-China I to China IV. Alkanes, alkenes, aromatics and some additional species in the exhaust were collected in Tedlar bags and analyzed using gas chromatography/mass spectrometry (GC-MS). Carbonyls were collected on 2,4-dinitrophenyhydrazine (DNPH) cartridges and analyzed using high-performance liquid chromatography (HPLC). Overall, 74 VOC species were detected from the tested vehicles, including 22 alkanes, 6 alkenes, 1 alkyne, 16 aromatics, 3 cyclanes, 10 halohydrocarbons, 12 carbonyls and 4 other compounds. Alkanes, aromatics and carbonyls were the dominant VOCs with weight percentages of approximately 36.4%, 33.1% and 17.4%, respectively. The average VOC emission factors and standard deviations of the Pre-China I, China I, China II, China III and China IV vehicles were 469.3 ± 200.1, 80.7 ± 46.1, 56.8 ± 37.4, 25.6 ± 11.7 and 14.9 ± 8.2 mg/km, respectively, which indicated that the VOC emissions significantly decreased under stricter vehicular emission standards. Driving cycles also influenced the VOC emissions from the tested vehicles. The average VOC emission factors based on the travel distances of the tested vehicles under urban driving cycles were greater than those under highway driving cycles. In addition, we calculated the ozone formation potential (OFP) using the maximum incremental reactivity (MIR) method. The results of this study will be helpful for understanding the true emission levels of light-duty gasoline vehicles and will provide information for controlling VOC emissions from vehicles in Beijing, China.

  18. An updated emission inventory of vehicular VOCs and IVOCs in China

    Science.gov (United States)

    Liu, Huan; Man, Hanyang; Cui, Hongyang; Wang, Yanjun; Deng, Fanyuan; Wang, Yue; Yang, Xiaofan; Xiao, Qian; Zhang, Qiang; Ding, Yan; He, Kebin

    2017-10-01

    Currently, the emission inventory of vehicular volatile organic compounds (VOCs) is one of those with the largest errors and uncertainties due to suboptimal estimation methods and the lack of first-hand basic data. In this study, an updated speciated emission inventory of VOCs and an estimation of intermediate-volatility organic compounds (IVOCs) from vehicles in China at the provincial level for the year of 2015 are developed based on a set of state-of-the-art methods and an abundance of local measurement data. Activity data for light-duty vehicles are derived from trajectories of more than 70 000 cars for 1 year. The annual mileage of trucks are calculated from reported data by more than 2 million trucks in China. The emission profiles are updated using measurement data. Vehicular tailpipe emissions (VTEs) and four types of vehicular evaporation emissions (VEEs), including refueling, hot soak, diurnal and running loss, are taken into account. Results show that the total vehicular VOC emissions in China are 4.21 Tg (with a 95 % confidence interval range from 2.90 to 6.54 Tg) and the IVOC emissions are 200.37 Gg in 2015. VTEs are still the predominant contributor, while VEEs are responsible for 39.20 % of VOC emissions. The control of VEEs is yet to be optimized in China. Among VTEs, passenger vehicles emissions have the largest share (49.86 %), followed by trucks (28.15 %) and motorcycles (21.99 %). Among VEEs, running loss is the largest contributor (81.05 %). For both VTEs and VEEs, Guangdong, Shandong and Jiangsu province are three of the highest, with a respective contribution of 10.66, 8.85 and 6.54 % to the total amounts of VOCs from vehicles. 97 VOC species are analyzed in this VOC emission inventory. i-Pentane, toluene and formaldehyde are found to be the most abundant species in China's vehicular VOC emissions. The estimated IVOCs are another inconvenient truth, concluding that precursor emissions for secondary organic aerosol (SOA) from vehicles are much

  19. An updated emission inventory of vehicular VOCs and IVOCs in China

    Directory of Open Access Journals (Sweden)

    H. Liu

    2017-10-01

    Full Text Available Currently, the emission inventory of vehicular volatile organic compounds (VOCs is one of those with the largest errors and uncertainties due to suboptimal estimation methods and the lack of first-hand basic data. In this study, an updated speciated emission inventory of VOCs and an estimation of intermediate-volatility organic compounds (IVOCs from vehicles in China at the provincial level for the year of 2015 are developed based on a set of state-of-the-art methods and an abundance of local measurement data. Activity data for light-duty vehicles are derived from trajectories of more than 70 000 cars for 1 year. The annual mileage of trucks are calculated from reported data by more than 2 million trucks in China. The emission profiles are updated using measurement data. Vehicular tailpipe emissions (VTEs and four types of vehicular evaporation emissions (VEEs, including refueling, hot soak, diurnal and running loss, are taken into account. Results show that the total vehicular VOC emissions in China are 4.21 Tg (with a 95 % confidence interval range from 2.90 to 6.54 Tg and the IVOC emissions are 200.37 Gg in 2015. VTEs are still the predominant contributor, while VEEs are responsible for 39.20 % of VOC emissions. The control of VEEs is yet to be optimized in China. Among VTEs, passenger vehicles emissions have the largest share (49.86 %, followed by trucks (28.15 % and motorcycles (21.99 %. Among VEEs, running loss is the largest contributor (81.05 %. For both VTEs and VEEs, Guangdong, Shandong and Jiangsu province are three of the highest, with a respective contribution of 10.66, 8.85 and 6.54 % to the total amounts of VOCs from vehicles. 97 VOC species are analyzed in this VOC emission inventory. i-Pentane, toluene and formaldehyde are found to be the most abundant species in China's vehicular VOC emissions. The estimated IVOCs are another inconvenient truth, concluding that precursor emissions for secondary organic

  20. Non-labeling multiplex surface enhanced Raman scattering (SERS) detection of volatile organic compounds (VOCs)

    DEFF Research Database (Denmark)

    Wong, Chi Lok; Dinish, U. S.; Schmidt, Michael Stenbæk

    2014-01-01

    -pillars. In this experiment, detections of acetone and ethanol vapor at different concentrations were demonstrated. The detection limits were found to be 0.0017 ng and 0.0037 ng for ethanol and acetone vapor molecules respectively. Our approach is a non-labeling method such that it does not require the incorporation of any...... of acetone and ethanol vapor was also successfully demonstrated. The vibrational fingerprints of molecular structures provide specific Raman peaks for different VOCs contents. To the best of our knowledge, this is the first multiplex VOCs detection using SERS. We believe that this work may lead to a portable...

  1. A generalized discontinuous PWM based neutral point voltage balancing method for three-level NPC voltage source inverter with switching losses reduction

    DEFF Research Database (Denmark)

    Li, Kai; Wei, Min; Xie, Chuan

    2017-01-01

    In order to control the neutral point voltage of inverter with discontinuous PWM (DPWM), this paper proposed a generalized discontinuous PWM (GDPWM) based neutral point voltage balancing method for three level neutral point clamped (NPC) voltage source inverter (VSI). Firstly, a triangle carrier ...

  2. Indigenous West African plants as novel sources of polysaccharide degrading enzymes: application in the reduction of the viscosity of cereal porridges

    NARCIS (Netherlands)

    Dicko, M.H.; Hilhorst, M.H.; Traore, A.S.

    2005-01-01

    Ethnobotanical and biochemical surveys revealed that some local plants from West Africa are novel sources of polysaccharide degrading enzymes such as amylases and glucanases. The study shows that these enzymes could be used for various biotechnological applications. In a crude extract of Curculigo

  3. Use of Oil Palm Waste as a Renewable Energy Source and Its Impact on Reduction of Air Pollution in Context of Malaysia

    Science.gov (United States)

    Begum, Shahida; P, Kumaran; M, Jayakumar

    2013-06-01

    One of the most efficient and effective solutions for sustainable energy supply to supplement the increasing energy demand and reducing environment pollution is renewable energy resources. Malaysia is currently the world's second largest producer and exporter of palm oil and 47% of the world's supply of palm oil is produced by this country. Nearly 80 million tonnes of Fresh Fruit Bunches (FFB) are processed annually in 406 palm oil mills and are generating approximately 54 million tonnes of palm oil mill effluent (POME), known to generate biogas consisting of methane - a Green House Gas (GHG) identifiable to cause global warming. This is 21 times more potent GHG than CO2. These two major oil palm wastes are a viable renewable energy (RE) source for production of electricity. If the two sources are used in harnessing the renewable energy potential the pollution intensity from usage of non-renewable sources can also be reduced significantly. This study focused on the pollution mitigation potential of biogas as biogas is a renewable energy. Utilization of this renewable source for the production of electricity is believed to reduce GHG emissions to the atmosphere.

  4. Leaf ontogeny dominates the seasonal exchange of volatile organic compounds (VOC) in a SRC-poplar plantation during an entire growing season

    Science.gov (United States)

    Brilli, Federico; Gioli, Beniamino; Fares, Silvano; Zenone, Terenzio; Zona, Donatella; Gielen, Bert; Loreto, Francesco; Janssens, Ivan; Ceulemans, Reinhart

    2015-04-01

    The declining cost of many renewable energy technologies and changes in the prices of fossil fuels have recently encouraged governments policies to subsidize the use of biomass as a sustainable source of energy. Deciduous poplars (Populus spp.) trees are often selected for biomass production in short rotation coppiced (SRC) for their high CO2 photosynthetic assimilation rates and their capacity to develop dense canopies with high values of leaf area index (LAI). So far, observations and projections of seasonal variations of many VOC fluxes has been limited to strong isoprenoids emitting evergreen ecosystems such tropical and Mediterranean forests as well as Citrus and oil palm plantation, all having constant values of LAI. We run a long-term field campaign where the exchange of VOC, together with CO2 and water vapor was monitored during an entire growing season (June - November, 2012) above a SRC-based poplar plantation. Our results confirmed that isoprene and methanol were the most abundant fluxes emitted, accounting for more than 90% of the total carbon released in form of VOC. However, Northern climates characterized by fresh summertime temperatures and recurring precipitations favored poplar growth while inhibiting the development of isoprene emission that resulted in only 0.7% of the net ecosystem carbon exchange (NEE). Besides, measurements of a multitude of VOC fluxes by PTR-TOF-MS showed bi-directional exchange of oxygenated-VOC (OVOC) such as: formaldehyde, acetaldehyde, acetone, isoprene oxidation products (iox, namely MVK, MAC and MEK) as well as ethanol and formic acid. The application of Self Organizing Maps to visualize the relationship between the full time-series of many VOC fluxes and the observed seasonal variations of environmental, physiological and structural parameters proved the most abundant isoprene ad methanol fluxes to occur mainly on the hottest days under mid-high light intensities when also NEE and evapotraspiration reached the highest

  5. One-electron reduction of N-chlorinated and N-brominated species is a source of radicals and bromine atom formation.

    Science.gov (United States)

    Pattison, David I; O'Reilly, Robert J; Skaff, Ojia; Radom, Leo; Anderson, Robert F; Davies, Michael J

    2011-03-21

    Hypochlorous (HOCl) and hypobromous (HOBr) acids are strong bactericidal oxidants that are generated by the human immune system but are implicated in the development of many human inflammatory diseases (e.g., atherosclerosis, asthma). These oxidants react readily with sulfur- and nitrogen-containing nucleophiles, with the latter generating N-halogenated species (e.g., chloramines/bromamines (RR'NX; X = Cl, Br)) as initial products. Redox-active metal ions and superoxide radicals (O(2)(•-)) can reduce N-halogenated species to nitrogen- and carbon-centered radicals. N-Halogenated species and O(2)(•-) are generated simultaneously at sites of inflammation, but the significance of their interactions remains unclear. In the present study, rate constants for the reduction of N-halogenated amines, amides, and imides to model potential biological substrates have been determined. Hydrated electrons reduce these species with k(2) > 10(9) M(-1) s(-1), whereas O(2)(•-) reduced only N-halogenated imides with complex kinetics indicative of chain reactions. For N-bromoimides, heterolytic cleavage of the N-Br bond yielded bromine atoms (Br(•)), whereas for other substrates, N-centered radicals and Cl(-)/Br(-) were produced. High-level quantum chemical procedures have been used to calculate gas-phase electron affinities and aqueous solution reduction potentials. The effects of substituents on the electron affinities of aminyl, amidyl, and imidyl radicals are rationalized on the basis of differential effects on the stabilities of the radicals and anions. The calculated reduction potentials are consistent with the experimental observations, with Br(•) production predicted for N-bromosuccinimide, while halide ion formation is predicted in all other cases. These data suggest that interaction of N-halogenated species with O(2)(•-) may produce deleterious N-centered radicals and Br(•).

  6. Reductive de-polymerization of kraft lignin for chemicals and fuels using formic acid as an in-situ hydrogen source.

    Science.gov (United States)

    Huang, Shanhua; Mahmood, Nubla; Tymchyshyn, Matthew; Yuan, Zhongshun; Xu, Chunbao Charles

    2014-11-01

    In this study, formic acid (FA) was employed as an in-situ hydrogen donor for the reductive de-polymerization of kraft lignin (KL). Under the optimum operating conditions, i.e., 300 °C, 1 h, 18.6 wt.% substrate concentration, 50/50 (v/v) water-ethanol medium with FA at a FA-to-lignin mass ratio of 0.7, KL (Mw∼10,000 g/mol) was effectively de-polymerized, producing de-polymerized lignin (DL, Mw 1270 g/mol) at a yield of ∼90 wt.% and polymerization of KL. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Impact of food intake on in vivo VOC concentrations in exhaled breath assessed in a caprine animal model.

    Science.gov (United States)

    Fischer, Sina; Bergmann, Andreas; Steffens, Markus; Trefz, Phillip; Ziller, Mario; Miekisch, Wolfram; Schubert, Jochen S; Köhler, Heike; Reinhold, Petra

    2015-12-15

    Physiological processes within the body may change emitted volatile organic compound (VOC) composition, and may therefore cause confounding biological background variability in breath gas analyses. To evaluate the effect of food intake on VOC concentration patterns in exhaled breath, this study assessed the variability of VOC concentrations due to food intake in a standardized caprine animal model. VOCs in (i) alveolar breath gas samples of nine clinically healthy goats and (ii) room air samples were collected and pre-concentrated before morning feeding and repeatedly after (+60 min, +150 min, +240 min) using needle trap microextraction (NTME). Analysis of VOCs was performed by gas chromatography and mass spectrometry (GC-MS). Only VOCs with significantly higher concentrations in breath gas samples compared to room air samples were taken into consideration. Six VOCs that belonged to the chemical classes of hydrocarbons and alcohols were identified presenting significantly different concentrations before and after feeding. Selected hydrocarbons showed a concentration pattern that was characterized by an initial increase 60 min after food intake, and a subsequent gradual decrease. Results emphasize consideration of physiological effects on exhaled VOC concentrations due to food intake with respect to standardized protocols of sample collection and critical evaluation of results.

  8. VOC identification and inter-comparison from laboratory biomass burning using PTR-MS and PIT-MS

    Science.gov (United States)

    C. Warneke; J. M. Roberts; P. Veres; J. Gilman; W. C. Kuster; I. Burling; R. Yokelson; J. A. de Gouw

    2011-01-01

    Volatile organic compounds (VOCs) emitted from fires of biomass commonly found in the southeast and southwest U.S. were investigated with PTR-MS and PIT-MS, which are capable of fast measurements of a large number of VOCs. Both instruments were calibrated with gas standards and mass dependent calibration curves are determined. The sensitivity of the PIT-MS linearly...

  9. Coins as gauge for growth: VOC- doits to probe Java’s deep monetisation, 1700-1800

    NARCIS (Netherlands)

    Feenstra, A.

    2013-01-01

    During the eighteenth century the VOC imported over a billion small copper coins (doits) to Java, which is a remarkable operation for the world’s largest enterprise at that time, since these coins were unfit to pay for the company’s wholesale trade. This paper argues that the VOC responded to Java’s

  10. The VOC filter regenerates thanks to the electrical current; Le filtre a COV se regenere grace au courant electrique

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, V.

    2005-05-01

    Designed by the Ecole des Mines of Nantes (France) in association with Sofrance filters manufacturing company, this new filter uses an activated carbon textile to adsorb the volatile organic compounds (VOCs). The regeneration of the filter is performed with an electrical current which heats the carbon fibers for the desorption of the VOCs by Joule effect. Short paper. (J.S.)

  11. CAPSTONE REPORT ON THE DEVELOPMENT OF A STANDARD TEST METHOD FOR VOC EMISSIONS FROM INTERIOR LATEX PAINT AND ALKYD PAINTS

    Science.gov (United States)

    The report gives details of a small-chamber test method developed by the EPA for characterizing volatile organic compound (VOC) emissions from interior latex and alkyd paints. Current knowledge about VOC, including hazardous air pollutant, emissions from interior paints generated...

  12. Development of a risk-based index for source water protection planning, which supports the reduction of pathogens from agricultural activity entering water resources.

    Science.gov (United States)

    Goss, Michael; Richards,