TY - JOUR. T1 - Biological aspects of constructing volatile organic compound emission inventories. AU - Monson, Russell K.. AU - Lerdau, Manuel T.. AU - Sharkey, Thomas D.. AU - Schimel, David S.. AU - Fall, Ray. PY - 1995/11. Y1 - 1995/11. N2 - The: emission of volatile organic compounds (VOCs) from vegetation is subject to numerous biological controls. Past inventories have relied heavily on empirical models which are limited in their ability to simulate the response of organisms to short- and long-term changes in their growth environment. In this review we consider the principal biochemical, physiological and ecological controls over VOC emission with specific reference to how such controls can be included in ecosystem-level inventories. A distinction is made between longer-term biological controls over basal VOC emission rates (rates determined under a standard set of environmental conditions) and instantaneous biological and environmental controls over instantaneous VOC emission rates ...
... -. Siting of the new wastewater treatment plant (WWTP) for the Massachusetts Water Resources Authority (MWRA) in Boston was based on an assumption of mitigation of total reduced sulfur (TRS) and volatile organic compound (VOC) emissions. Collection and treatment of exhaust streams from potential emission sources was recommended. Best Available Control Technology (BACT) for VOC control was conservatively suggested to consist of wet scrubbing followed by carbon adsorption based on initial sampling performed in 1988 during facilities planning, which estimated uncontrolled VOC emissions in excess of 1000 tons per year. This concept was carried forward to the design phase in 1990, concurrent with an extensive air emissions testing and pilot treatment program at the MWRAs existing primary treatment plant. Results of the pilot program, however, indicated source VOC concentrations well below what was expected as a
VOC emissions from melamine films and finish foils. The paper presents results of investigations on VOC emissions from melamine films and finish foils, i.e. materials used to refine surface of wood-based materials. Compound adsorption was carried out on the Tenax TA solid sorbent. Volatile organic compounds were analysed with the assistance of gas chromatography coupled with mass spectrometry and thermal desorption (GC/MS/TD). It was concluded, on the basis of the obtained research results, that the tested finishing materials were characterised by relatively low levels of noxious emissions ...
VOC emission profile is an important parameter to describe the building materials and consumer products for their impact on indoor air quality (IAQ). Emission profiles are dependent on the test conditions. It is therefore very important to standardize testing conditions in order to compare emission factors and decay constants reported by various testing laboratories. Standard chamber test conditions (Chamber temperature of 23 C, relative humidity of 50 %, air change rate of 1 ACH, and specimen loading ratio of 0.4 m{sup 2}/m{sup 3}) have been proposed for using small environment chamber (0.05 m{sup 3}) by an international consortium research program led by the Institute for Research in Construction, NRCC. VOC emissions (excluding formaldehyde) from three building materials, a particleboard, a carpet with rubber backing and a vinyl floor tile were measured under above defined test conditions. Samples of the chamber air were collected using multi-sorbent tubes during the chamber tests, and ...
Emission inventories defining regional and global biogenic volatile organic compounds (VOC) emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects). The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. 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 the most dominant compound emitted followed by monoterpenes, methanol and ...
P1.27 Studies of Volatile Organic Compounds in Ambient Air in New York City. Mohamed Bangura, Medgar Evers College, City University of New York, Brooklyn, NY; and J. Dick. Volatile organic compounds (VOCs) including benzene and its derivatives contribute significantly to the pollution of urban air; at low altitudes, VOCs also enhance ozone production. Monitoring VOC in urban air has important health implications, especially since asthma and other lung diseases in inner city communities are above the national average. In addition, weather variables such as wind speed, atmospheric pressure, temperature and humidity affect dispersal patterns and concentrations. Present methods for the determination of VOCs in ambient air are expensive and complex, simpler methods are required. Tetraglyme (tetraethylene glycol dimethyl ether) is used to scrub a variety of VOCs in ambient air. The chilled tetraglyme traps VOCs as the air is bubbled through it. The VOCs are dispersed in water, which is analyzed by ...
Article What is a Volatile Organic Compound (VOC)?. What is a Volatile Organic Compound (VOC)? Our products are known for monitoring many different gases, but if you look closely at the description of some of them, you will see that it mentions the ...
Uncorrected OCR) Abstract of thesis entitled. DEVELOPMENT OF PIEZOELECTRIC CRYST AL DETECTORS FOR SENSING BACTERIA IN WATER AND DETERMINING VOLATILE ORGANIC COMPOUNDS IN AIR. Submitted by. WongYukYan. for the Degree of Master of Philosophy at The University of Hong Kong. in January 2000. The applicability of piezoelectric (P/Z) crystal sensors as detectors for determining volatile organic compounds (VOCs) in air, and sensing bacteria in water, has been investigated in the present study. The detectors developed provide a simple and sensitive on-site method for determining total organic vapours in air for occupational health protection, and provide a specific and economic method for determining Salmonella in water for food poisoning. cases.. For VOC determination in workplace air, a light and portable P/Z crystal detector has been developed. To reduce the interference of high humidity on the monitoring of organic vapours, the moisture content in the air. sampled was removed by two different drying ...
Free Online Library: Laboratory evaluation of volatile organic compounds emissions from coated and uncoated oriented strandboard. by Forest Products Journal; Business Forest products industry Emissions (Pollution) Case studies Oriented strand board Volatile organic compounds Influence
The current standard is developed for the purpose of implementation of Environmental Protection Law of the Peoples Republic of China and Law of the Peoples Republic of China on Prevention and Control of Environmental Pollution by Solid Waste, protecting the environment, ensuring human health and standardizing the methods for determination of volatile organic compounds in solid waste. The current standard specifies the headspace-gas chromatography method for determination of volatile organic compounds in solid waste. The current standard is released for the first time. ...
The current standard is developed for the purpose of implementation of Environmental Protection Law of the Peoples Republic of China and Law of the Peoples Republic of China on Prevention and Control of Environmental Pollution by Solid Waste, protecting the environment, ensuring human health and standardizing the methods for determination of volatile organic compounds in solid waste. The current standard specifies the headspace-gas chromatography method for determination of volatile organic compounds in solid waste. The current standard is released for the first time.. ...
Biogenic emissions of the volatile organic compounds isoprene and monoterpenes (BVOCs) can contribute to tropospheric ozone and secondary particle formation and have indirect effects on climate change. While there are few studies of BVOC emissions from European towns and cities, several studies in North America indicate that the urban tree canopy may be a significant source of BVOC compounds, contributing to ozone and particle formation in the urban air-shed. Here, BVOC emissions from the U.K. West Midlands (UKWM) metropolitan area were estimated and compared with anthropogenic VOC emission estimates, and with BVOC emission estimates for other urban and U.K. regions. Monoterpene and isoprene emission potential estimates for the UKWM urban land-use classes spanned as much as two orders of magnitude, from 17-104 g·km-2·h-1 and from 42-1570 g·km-2·h-1, respectively. Isoprene emission potential estimates for the UKWM urban land classes (42-530 g·km-2·h-1) were of the same order of magnitude as ...
The purposes of this project were to develop and validate a sampling and analysis methodology for determination of volatile organic compound (VOC) concentrations in health care settings and to model results for incorporation into a job-exposure matrix. This project was part of a larger epidemiologic study to assess exposures to asthmagenic cleaning and disinfecting products among healthcare worker
An analytical method has been established for the quantitative determination of 48 gaseous volatile organic compounds (VOCs) that were detected in the outdoor environment in Western Singapore by Thermal Desorption Gas Chromatography Mass Spectrometry (TD-GCMS). Tenax/Carbopack X multi-sorbent tubes were evaluated for active sampling performance and the method was validated using VOC standard solutions. The procedure exhibited repeatability with relative standard deviation (%RSD) values ≤ 10%, linearity with R2 values ≥ 0.99 for concentrations from 0.02 to 500 ng, VOC standards breakthrough ≤ 5% , tube desorption efficiencies ~100% and the majority of recoveries were between 61% to 120%. 30 mL/min flow rate coupled with sampling volumes of 1 L and 5 L gave the best results for sampling breakthrough and reproducibility during air sampling. Most of the target analytes exhibited acceptable breakthrough ≤ 5%, reproducibility ≤ 20% and method detection limits below 0.5 ppbv. The analyte ...
The concentrations of formaldehyde, individual volatile organic compounds (VOCs) and total VOCs (TVOC) were measured in four new manufactured houses on three occasions over nine months following construction. Ventilation rates were also measured. A mass-balance model was used to calculate area-specific emission rates of the target analytes. Formaldehyde concentrations were all less than a guideline value of 50 ppb. One-half of the 58 target VOCs had median concentrations at or below 1 ppb. The most abundant VOCs were terpene hydrocarbons, ethylene glycol, hexanal, 2-butanone and acetic acid. Concentrations of hexanal, other aldehydes and acetic acid often exceeded their odor thresholds. The median TVOC concentration was 1.6 mg m-3. In general, there were no large decreases in the emission rates of individual VOCs or TVOC over the course of the study. The data suggested that wood products were a dominant source of VOCs in all houses.. ...
Air sampling, using sorbents, thermal desorption and gas chromatography, is a versatile method for identifying and quantifying trace levels of volatile organic compounds (VOCs). Thermal desorption can provide high sensitivity, appropropriate choices of sorbents and method parameters can accommodate a wide range of
Formaldehyde Tester I Application Formaldehyde Tester I Application Formaldehyde mattress mattress tester is mainly applied to formaldehyde, VOC emission test
Formaldehyde (HCHO) columns measured from space provide constraints on emissions of volatile organic compounds (VOCs). Quantitative interpretation requires characterization of errors in HCHO column retrievals and relating these columns to VOC emissions. Retrieval error is mainly in the air mass factor (AMF) which relates fitted backscattered radiances to vertical columns and requires external information on HCHO, aerosols, and clouds. Here we use aircraft data collected over North America and the Atlantic to determine the local relationships between HCHO columns and VOC emissions, calculate AMFs for HCHO retrievals, assess the errors in deriving AMFs with a chemical transport model (GEOS-Chem), and draw conclusions regarding space-based mapping of VOC emissions. We show that isoprene drives observed HCHO column variability over North America; HCHO column data from space can thus be used effectively as a proxy for isoprene emission. From observed HCHO and isoprene profiles we find an HCHO molar ...
Oxygenated volatile organic compounds ((O)VOCs) contribute to ozone formation, affect the oxidising capacity of the troposphere and are sources of growth, and in some cases formation, of aerosols. It is therefore important to identify and quantify sources of (O)VOCs in the troposphere. In the late 1990s a unique technique for quantification of organic trace gas species, proton transfer reaction mass spectrometry (PTR-MS) was developed. PTR-MS potentially offers rapid response and high sensitivity without the need for sample preconcentration. Concentrations can be derived from the PTR-MS either by calibration or can be calculated from measured ion count rates and kinetic considerations. In this work, the methodology of PTR-MS application is critically assessed. The uncertainties and inaccuracies associated with each parameter employed in the calculation of concentrations are reviewed. This includes a critical appraisal of models for the calculation of the collisional rate constant currently ...
The biogenic volatile organic compounds (VOCs) in the ambient air of the Hobart Air Shed and in the emissions from selected Tasmanian native trees and understorey shrubs were measured. The emission rates were then related to the plants essential oils content, which had been extracted by hydro-distillation. The VOCs in the ambient air of native forests have not previously been studied in Australia. This study used multi-adsorbent cartridge adsorption/thermal desorption and Gas Chromatography-Mass Spectrometry. The type, quantity, source and variation of the VOCs were investigated. The concentration of VOCs in the atmosphere surrounding vegetation in the Hobart Air Shed was determined. In all, 129 compounds of eight classes were detected. Ofthese, 11 compounds were National Pollutant Inventory substances and 32 were considered biogenic; however, this estimate is conservative. The concentration of total VOCs in these ambient air measurements varied between 4.43 x 10- 10 g L- 1 and 3.04 x 10-9 g ...
Volatile organic compounds (VOCs) and indoor air quality, what VOCs are and where they come from, health concerns, how to avoid VOCs, and proper ventilation tips.
Abstract Volatile organic compounds (VOCs) are trace substances found in exhaled breath. In the past years numerous studies have underlined the close connection between VOCs and various diseases. Several VOCs classes have been identified, such as: hydrocarbons, sulfur containing VOCs, amino containing VOCs or oxygen containing VOCs. The specific focus of the present review is to address the topic of VOCs fingerprint in several specific diseases such as: lung disease, heart disease, breast disease, Cohns disease, ulcerative colitis, gastro-enteric affections, schizophrenia and in vitro cell cultures…. ...
Predators and parasitoids are important natural enemies of herbivorous insects. By reducing the abundance of herbivores, they can help protect plants from damage. Parasitoids in particular can use herbivore-induced plant volatiles (HIPVs) as host-searching cues [1, 2]. Such volatile-mediated tritrophic interactions have a considerable potential to shape ecosystem dynamics [3], but it remains unclear to what extend the plant signals are emitted by the plant to specifically attract natural enemies of herbivores [4]. If HIPVs are indeed emitted by the plant to attract the third tropic level, specificity of the signals should be an important aspect of the interactions [5]. This is particularly relevant under natural conditions, where plants are often attacked by non-hosts or by multiple herbivores simultaneously. While specialist parasitoids can distinguish between plants attacked by hosts and plants attacked by non-hosts using HIPV cues [6], the impact of non-hosts feeding on the same plant as the ...
Altech provides accurate and fast measurements of VOC (Volatile Organic Compounds). We offer complete VOC CEMS or discrete analyzers.
In this study, single-lung ventilation was used to detect differences in the volatile organic compound (VOCs) profiles between lung tissues in healthy and affected lungs. In addition, changes that occurred after lung cancer resection in both the VOCs profiles of exhaled breath from ipsilateral and contralateral lungs and the VOCs profiles of exhaled breath and blood sample headspaces were also determined. Eighteen patients with non-small cell carcinoma were enrolled. Alveolar breath samples were taken separately from healthy and diseased lungs before and after the tumor resection. Solid phase microextraction-gas chromatography/mass spectrometry was used to assess the exhaled VOCs of the study participants. The VOCs exhibited significant differences between the contralateral and ipsilateral lungs before surgery, the contralateral and ipsilateral lungs after surgery, the ipsilateral lungs before and after surgery, and the blood samples from before and after surgery; 12, 19, 12 and 5 characteristic ...
Volatile organic compounds are chemicals used to manufacture and maintain building materials, interior furnishing, cleaning products and personal care products. "Volatile" means that these chemicals evaporate or can easily get into the air at room temperature. "Organic" means these chemicals are carbon based. The term "chemical emissions" refers to VOCs as they evaporate into the air from products.. Studies by the EPA and other researchers from the New York Department of Health, have found that VOCs are common in indoor environments and that their levels may be two to a thousand times higher than outdoors. There may be anywhere from 50 to hundreds of individual VOCs in the indoor air at any one time. Some may produce objectionable odors at very low levels, but many have no noticeable smell.. ...
Analyses for Volatile Organic Compound Monitoring were conducted under procedures using concepts of EPA Method TO-15 "Determination of Volatile Organic Compounds (VOCs) in Air Collected in Specially-Prepared Canisters and Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS)" (1999).Special quality assurance requirements for these activities were detailed in the "Quality Assurance Project Plan for Volatile Organic Compound Monitoring", prepared by WTS. CEMRC personnel wrote procedures for this project under the CEMRC Quality Assurance Plan, which were verified, validated, and placed in the CEMRC Document Control Program. Procedures were composed to include QA requirements from EPA Method TO-15 and all WIPP documents relevant to the Confirmatory Monitoring Program. See Table 4-2 for a list of CEMRC Procedures for Confirmatory Monitoring.. In November 2006, a WIPP permit modification incorporated an expansion of sampling in the Volatile Organic Compounds Monitoring Program. Originally, the ...
An air-conditioned coach is an important form of transportation in modern motorized society; as a result, there is an increasing concern of in-vehicle air pollution. In this study, we aimed to identify and quantify the levels of volatile organic compounds (VOCs) and carbonyl compounds (CCs) in air samples collected from the cabins of newly produced, medium- and large-size coaches. Among the identified VOCs and CCs, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acrolein/acetone, and isovaleraldehyde were relatively abundant in the cabins. Time was found to affect the emissions of the contaminants in the coaches. Except for benzaldehyde, valeraldehyde and benzene, the highest in-vehicle concentrations of VOCs and CCs were observed on the 15th day after coming off the assembly line, and the concentrations exhibited an approximately inverted U-shaped pattern as a function of time. Interestingly, this study also showed that the interior temperature of the coaches significantly affected the VOCs
Volatile Compounds Profile of Sous-Vide Cooked Pork Cheeks as Affected by Cooking Conditions Vacuum Packaging, Temperature and Time. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
The FLIR GF320 is an IR camera for optical gas imaging. It visualizes and pinpoints leaks of Volatile Organic Compounds (VOCs), without the need to shut down the operation. This portable camera can greatly improve operator safety, by detecting emissions at a safe distance.
Volatile organic compounds (VOCs) emitted into headspace over discrete electronic components including resistors, capacitors, diodes, transistors, and transformers were i..
Applied Technical Services wants to help keep clients compliant with industry regulations and consumer products safe from Volatile Organic Compounds. With our newly acquired Thermal Desorption unit, we can test all kinds of parts for VOCs according to VDA 278.
The spatiotemporal variability of ambient volatile organic compounds (VOCs) in Tehran, Iran, is not well understood. Here we present the design, methods, and results of the Tehran Study of Exposure Prediction for Environmental Health Research (Tehran SEPEHR) on ambient concentrations of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene (BTEX), and total BTEX. To date, this is…
A nonrandom group of 40 volunteers participated in a study to determine the level of correlation between three methods of sampling for volatile organic compounds (VOC): organic vapor badges, charcoal tubes, and blood VOC levels. Each of 40 volunteers provided blood samples for analysis. Nineteen subjects wore organic vapor badges for at least 5 hours, and 24 subjects provided personal breathing zo
The use of volatile organic compounds VOCs to detect mold growth in damp buildings depends on a comprehensive knowledge of the biosynthetic pathways available to indoor molds as well as their biological variation. Recent reports concerning VOCs formed during the growth of molds from damp buildings on laboratory substrates indicate considerable...
Chlorinated volatile organic compounds (CVOCs) are toxic chemical entities emitted invariably from stationary thermal operations when a trace of chlorine is present. Replacing the high-temperature destruction operations of these compounds with catalytic oxidation has led to the formulation of various potent
Which Filtration Unit is Best for Persons with Chemical Injuries of the Respiratory Tract…How Should You Choose?. Breathe-Rite pharmacists receive many calls asking to help clarify the question "……which HEPA/Residential Filtration System is right for me?". Many times these questions are easily answered over the phone. Generally we can direct individuals to our blog site, where comparisons are set side-by-side.. There are times, however, in which our patients have a more specific damage to the lung or an illness which requires special, individual attention.. In the past months we have been addressing these chemical injuries with more frequency. These are occurrences where chemical or physical damage has been done to the lungs. This may occur when there has been exposure to asbestos, or Volatile Organic Compounds and in some cases associated particulates. We include the gases or fumes given off from resins, paints, epoxys, sealers, and the various ethers used in modern plastics and ...
Read "A minimally-invasive method for profiling volatile organic compounds within postmortem internal gas reservoirs, International Journal of Legal Medicine" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
By means of a new method Aarhus University scientists have demonstrated that there is a relation between the quality of packaged wild rocket after harvest and the release of volatile organic compounds. In the long term this new method may be beneficial to the industry as well as consumers.
The DIY Network experts explain how volatile organic compounds, found in paint, caulk, cleaning supplies, carpet and wood, can be damaging to your health.
Wilson, Susan C. and Burnett, Victoria and Waterhouse, Keith S. and Jones, Kevin C. (1994) Volatile organic compounds in digested United Kingdom sewage sludges. Environmental Science and Technology, 28 (2). pp. 259-266. ISSN 0013-936X Full text not available from this repository ...
ABSTRACT: This data set reports concentrations of biogenic volatile organic compounds (BVOCs) collected from tethered balloon-sampling platforms above selected forest and pasture sites in the Brazilian Amazon in March 1998, February 1999, and February 2000. The air samples were collected from forested sites in Brazil: the Tapajos forest (Para) in the Tapajos/Xingu moist forest; Balbina (Amazonas) in the Uatuma moist forest; and Jaru (Rondonia) in the Purus/Madeira moist forest. Two other sites were also located in Rondonia: at a forest reserve (Rebio Jaru) and a pasture (Fazenda Nossa Senhora Aparecida). The BVOCs measured included isoprene, alpha and beta pinene, camphene, sabinene, myrcene, limonene, and other monoterpenes. Approximately 24 to 40 soundings, including as many as four VOC samples collected simultaneously at various altitudes, were made at each site. There is one comma-delimited data file with this data set.. daac.ornl.gov ...
This webinar discusses how to analyze volatile organic compounds and semi-volatile organic compounds in a single air analysis. The focus of the discussion is on two main applications, Soil Gas and Manufacturer Gas Plant Sites, using the technique of Automated Thermal Desorption.
Rice has been fermented to enhance its application in some foods. Although various microbes are involved in rice fermentation, their roles in the formation of volatile compounds, which are important to the characteristics of fermented rice, are not clear. In this study, diverse approaches, such as partial least squares-discriminant analysis (PLS-DA), metabolic pathway-based volatile compound formations, and correlation analysis between volatile compounds and microbes were applied to compare metabolic characteristics according to each microbe and determine microbe-specific metabolites in fermented rice inoculated by molds, yeasts, and lactic acid bacteria. Metabolic changes were relatively more activated in fermented rice inoculated by molds compared to other microbes. Volatile compound profiles were significantly changed depending on each microbe as well as the group of microbes. Regarding some metabolic pathways, such as carbohydrates, amino acids, and fatty acids, it could be observed that ...
Ascocoryne sarcoides is an endophytic filamentous fungus isolated from Northern Patagonia that can produce petroleum-like fuel compounds directly from cellulose (Strobel et al., 2008). The aim of this project was to study volatile organic compound production by A. sarcoides. The project is different from many other cellulosic biofuel projects that explore alcohol production from pre-treated biomass fermentation. It focuses on the ability of A. sarcoides to convert cellulose and related simple sugars to fuel-related hydrocarbons. The influence of environmental conditions on the growth characteristics and compounds produced from normal metabolic processes was explored. Quantification of volatile production from growth on glucose showed the major compounds were ethanol and acetaldehyde, with the remainder of volatiles near 2 ppm from a continuously aerated culture. These volatiles included compounds of fuel-interest such as benzaldehyde, nonanal, 1-octen-3-ol and 1-butanol, 3-methyl-. Notable ...
Qualitative results are presented from analysis of volatile and semi-volatile organic compounds (VOCs/SVOCs) obtained through sampling of gaseous effluent and condensed particulates during a series of experimental house fires conducted in a real house. Particular emphasis is given to the 16 polycyclic aromatic hydrocarbons (PAHs) listed by the Environmental Protection Agency due to their potentially carcinogenic effects. The initial fuel packages were either cooking oil or a single sofa; these were burned both alone, and in furnished surroundings. Experiments were performed at different ventilation conditions. Qualitative Gas Chromatography-Mass Spectrometry (GC-MS) analysis found VOC/SVOC releases in the developing stages of the fires, and benzo(a)pyrene - the most carcinogenic PAH - was found in at least one sampling interval in the majority of fires. A number of phosphorus fire retardants were detected, in both the gaseous effluent and particulates, from fires where the initial fuel source ...
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Organic aerosol from the oxidation of biogenic organic compounds: a modelling study Outline The atmosphere and volatile organic compounds Organic aerosols: How formed? Why of importance? BOREAM Model for biogenic organic aerosol formation Model results: Comparisons with chamber experiments How well do we model aerosol from α- and β-pinene?
Poster (2017, October 20). Despite the growing interest for oxygenated volatile organic compounds (OVOC) over the last 15 years due to their role in the atmospheric chemistry, current knowledge about OVOC exchanges by grassland and ... [more ▼]. Despite the growing interest for oxygenated volatile organic compounds (OVOC) over the last 15 years due to their role in the atmospheric chemistry, current knowledge about OVOC exchanges by grassland and the environmental factors driving them remains lacunar. However, those ecosystems represent an important part of the total earth surface (13.37%). This study conducted on a grazed grassland therefore aims to quantify OVOC exchanges over full grazing seasons in order to understand the mechanisms behind these exchanges. It took place within the activities of the CROSTVOC project (CROp Stress VOC) and therefore gives an important attention to the stress induced fluxes. BVOC flux measurements were performed with a PTR-MS for the measurements of OVOC ...
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Have you ever noticed the strong odor that a new memory foam mattress has? This odor is due chemicals in your mattress. Breathing this in can be very harmful.
Heated Soil Vapor Extraction (HSVE) is a technology that has been used successfully to clean up subsurface soils at sites containing chlorinated solvents and petroleum hydrocarbons. The costs have been extremely high due to the large amount of energy required to volatilize high molecular weight polycyclic aromatic hydrocarbon (PAH) compounds present in the soil matrix. One remediation contractor states that hydrocarbons are oxidized in situ by achieving temperatures in the ,1000 F range near the heaters [1]. A critical question is whether the volatile portion of manufactured gas plant (MGP) hydrocarbons (VOCs) can be stripped out at lower temperatures such that the remaining contaminants will be unavailable for transport or subsequent dissolution into the groundwater. Soil remediation by heated soil vapor extraction system is a relatively new technology developed by Jay Jatkar Inc. (JJI) along with the University of Wisconsin-Milwaukee [2]. The areas around chemical companies or waste disposal ...
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The Air Monitoring Section operates the divisions statewide ambient air monitoring network for the measurement of EPA criteria pollutants- ozone, particulate matter, nitrogen oxides, carbon monoxide and sulfur dioxide, as well as meteorological parameters such as wind speed and direction, temperature, barometric pressure, precipitation and solar radiation. The air monitoring network includes sampling and analyses for numerous air toxics compounds including many volatile organic compounds such as benzene and 1,3-butdiene, carbonyl compounds such as formaldehyde and acetaldehyde, toxic metals such as lead and arsenic, and semi volatile organic compounds such as naphthalene and benzo (a) pyrene. Monitoring sites within the network are participants in EPA National Networks such as SLAMS (State and Local Air Monitoring Stations), NCORE (National Core Monitoring Stations), NATTS (National Air Toxics Trends Stations), IMPROVE (Interagency Monitoring of Protected Visual Environments) and CSN/STN ...
For the most part, achieving a clear understanding of the biology and biochemistry of roots has remained difficult due to the underground growth habit of the plants hidden half. This underground habit poses major technical difficulties for root study and has hindered biochemical research in particular. A recent reincarnation of a classic plant organ culture system, root culture, has proven extremely useful in reinvigorating research on root metabolism. The soil microorganism Agrobacterium rhizogenes causes the hairy root disease, which is characterized by the proliferation of adventitious roots at the infection site. Hairy roots are able to express root-specific biosynthetic pathways such as the synthesis of hyoscyamine, β-carbolines, and rosmarinic acid among other metabolites at levels equal to or greater than in the roots in planta (Flores et al., 1999; Bais et al., 2001, 2002a, 2002b; Vivanco et al., 2002). In addition to secondary metabolites, hairy roots can produce and secrete bioactive ...
Background We aimed to assess the content of electronic cigarette (EC) emissions for five groups of potentially toxic compounds that are known to be present in tobacco smoke: nicotine, particles,...
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Many of the functional biochemical tests I do regularly show evidence of toxic stress, which we can then be investigated by other means. For example, when measuring levels of superoxide dismutase, it is common to find the gene that codes for SODase is blocked. This can be investigated further by doing DNA adducts. DNA adducts looks at a whole range of chemicals that may be stuck onto DNA - this is an important thing to know because a chemical stuck onto DNA is potentially a pre-malignant condition. See DNA adducts Tests of Mitochondrial Function Profile often show blockage to translocator protein. This can be investigated further by looking at chemicals stuck on to translocator protein. See Translocator protein studies Fat biopsy for pesticides or Volatile Organic Compounds - this is an extremely useful way of looking at what may be stuck in ones fat and can pick up a whole range of pesticides and volatile organic compounds. It is a very easy test to do - just the fat contained in the bore of ...
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Leukemia is a group of cancers that usually begin in the bone marrow and result in high numbers of abnormal and dysfunctional white blood cells. Many studies were carried out to investigate...
Cleaning products are known to release VOCs - volatile organic compounds - into the air as you use them. Some VOCs are harmless, but many are quite harmful to our health. They are linked to asthma and cancer, for example. In a small study done by Environmental Defence, the VOC levels in homes after cleaning increased by 120% with conventional cleaners. Even "green" cleaners increased VOC concentrations, but only by 30%.. Now, you might be thinking, OK, what can I look for on a label to avoid these chemicals?. Heres the problem: cleaning products in Canada and the US do not have to disclose ingredients on the label. At all. Which means that some brands will disclose partial ingredients making you think its the whole story. But most conventional products dont list any (or they provide useless information like "non-ionizing surfactant" and "naturally-derived fragrance").. The other issue is that the VOCs can react to other chemicals in the air to form entirely different substances. Like ...
... Description. Membrane separation technology has been designed by U.S. Department of Energy (DOE) to treat vapor streams that contain dilute concentrations of volatile organic compounds (VOCs). The technology involves the preferential transport of organic vapors through a nonporous gas membrane. Membranes are typically made of a polymer, and are designed for each application. In the DOE system, the vapors are then condensed, and a liquid solvent is recovered.. Limitations and Concerns. Membranes have difficulty handling fluctuations in VOC concentrations. Separation technology is not cost effective when dealing with several different contaminants at once.. Applicability. The targeted contaminants for membrane separation technology are VOCs in vapor streams exiting treatment systems.. Technology Development Status. Membrane separation has commercial applications in process engineering. It is relatively new for use in the remediation field, and it is a pilot project.. Web ...
Ultra-sensitive, high-resolution, real-time trace gas analyzers based on Proton Transfer Reaction - Mass Spectrometry (PTR-MS) and proprietary SRI-MS technology: the IONICON PTR-TOFMS and PTR-QMS series. OEM time-of-flight mass spectrometers. LCU Trace Calibation Devices.
Ultra-sensitive, high-resolution, real-time trace gas analyzers based on Proton Transfer Reaction - Mass Spectrometry (PTR-MS) and proprietary SRI-MS technology: the IONICON PTR-TOFMS and PTR-QMS series. OEM time-of-flight mass spectrometers. LCU Trace Calibation Devices.
The US EPAs Compendium Method TO-14A, "Determination of Volatile Organic Compounds (VOCs) in Ambient Air Using Specially Prepared Canisters With Subsequent Analysis By Gas Chromatography" is used extensively by analysts for both ambient air studies and indoor air quality studies. SPECTRA TO-14A VOC standards are part of the HiQ specialty gases product range from Linde Gas. Our TO-14A calibration gas mixture is directly traceable analytically to NIST and consists of 39 components at concentrations of either one ppm or one hundred ppb in a balance of nitrogen. All SPECTRA TO-14A standards have one year guaranteed stability and shelf life. Linde can also supply a variety of VOC calibration standard subsets ...
The microbial and chemical signatures reported here provide evidence that surface-borne microorganisms present in the indoor environment play a role in indoor chemistry. There were clear quantitative and qualitative differences in the metabolic profiles between experimental samples and blanks. Microbial metabolism is just one potential source for many VOCs found in indoor environments [60], and it is possible that some of the sampled volatile molecules were derived from absorption and desorption on surface materials. Nevertheless, many of the same compounds seen in experimental samples are also identified when microbes are grown in isolation. For example, in our analysis of soluble compounds, roughly 25% of the compounds observed on the indoor experimental samples were also observed from cultures. Likewise, the SCFAs and MCFAs that were abundant on household surfaces are common VOCs emitted from microbes grown on a variety of substrates [60]. And most notably, VOC concentrations scale with ...
Coming to a conclusion, this wonderful, informative and very interesting book presents an excellent overview of small volatile organic compounds and their role in our life and environment. Really fascinating is the entirety of scientific disciplines which were addressed by this book. -Flavour and Fragrance Journal, 2011 … this book deserves to be a well-used reference in the library of any laboratory specialising in VOC. -Chemistry World, 2011 Volatile compounds are molecules with a relatively low molecular weight allowing for an efficient evaporation into the air. They are found in many areas of our everyday-life: they are responsible for the communication between species such as plants, insects or mammals; they serve as flavours or fragrances in many food products or perfumed consumer articles; and they play an important role in atmospheric chemistry. This book takes an interdisciplinary approach to volatile molecules. Review-style introductions to the main topics in volatile
IDT offers gas sensors for TVOC, VOC, hydrogen gas, flammable gas, and others. The high-performance MOx sensors address leak detection, indoor air quality, and other applications. Get more information.
An analytical TD-GC-MS method was developed and used for the assessment of volatile organic compounds (VOCs) released from the blood plasma of dogs with/without cancer. VOCs released from 40 samples of diseased blood and 10 control samples were compared in order to examine the difference between both sample groups that were showing qualitatively similar results independent from the diseases presence. However, mild disturbances in the spectra of dogs with cancer in comparison with the control group were observed, and six peaks (tentatively identified by comparison with mass spectral library as hexanal, octanal, toluene, 2-butanone, 1-octen-3-ol and pyrrole) revealed statistically significant differences between both sample groups, thereby suggesting that these compounds are potential biomarkers that can be used for cancer diagnosis based on the blood plasma TD-GC-MS analysis. Statistical comparison with the application of principal component analysis (PCA) provided accurate discrimination between the
Berkeley Analytical provides furniture testing services as per various standards to evaluate VOC emissions, formaldehyde & phthalates emissions in wood.
Almost everyone has at one time or another walked into a newly constructed or recently renovated home or office and comment about the new smell. While the odor is pleasant to some, and may invoke feelings of a clean and fresh indoor environment, quite often it actually means the person is being exposed to elevated levels of volatile organic compounds (VOCs)., , , , The U.S. Environmental Protection Agency (EPA) describes VOCs as organic chemical compounds with a composition that makes it po...
courses.lumenlearning.com/boundless-chemistry/... CachedFunctional Groups. Functional groups refer to specific atoms bonded in a certain arrangement that give a compound certain physical and chemical properties. Alcohols. Alcohols are functional groups characterized by the presence of an -OH group. Identify the general properties of the alcohol functional group. Ethers. Ethers are a class of organic compounds characterized by an oxygen atom connected to two alkyl or aryl groups. Define the term "ether" as it relates to organic compounds. Aldehydes and Ketones. Aldehydes and ketones are classes of organic compounds that contain a carbonyl (C=O) group. Identify the general properties of ketones and aldehydes. See all full list on courses.lumenlearning.com ...
Student Guided Notes and PowerPoint for Organic Compounds. 110 Slides, Built in Review Questions, and Great Video Links for each Organic Compound. This Bundle addresses Organic Compounds at its BEST! Great Graphics, Song Video Links, Narrative Video Clips, Graphic Organizers and MORE.
As an alternative, if you want convenience of using tap water, boiling humidifiers can be a better, more convenient choice since they leave minerals behind in the water (which is why the water will turn black after several runnings without cleaning). However, aside from the fact that this will heat your home (a fine side effect during the winter), another fun fact is that tap water also contains VOCs (volatile organic compounds) in it (as seen in a city water report, IE [2]). When you boil the water, these organic compounds are released into the air. VOCs, in high quantities, can crowd out the availability of oxygen and can make the room feel stuffy and make it more difficult to breath. This effect is made worse by the fact that humidifiers usually require the windows and doors to be closed for them to do their job. Personally, for a boiling humidifier, I find that targeting 35-45% humidity is a nice compromise between convenience, keeping my room from getting too dry, and keeping the VOC levels ...
At 15:04 00-02-14 -0500, you wrote: , , ,We are investigating Tertiary-Butyl Acetate as a replacement for current ,hand wipe & paint prep techniques such as MEK. Apparently, the EPA is ,looking into delisting it as a VOC, but I have not been able to find any ,technical data concerning this solvent. Were also exploring other possible ,substitutions as this could be a replacement for VOCs in paints thereby ,reducing our VOC emissions at the depots and field units. , ,I have exhausted all the common solvent databases from the EPA and the DOD, ,but have come up empty handed. If anyone has any information concerning ,this solvent, please reply. Thanks! , ,Tim Provens ,Environmental Engineer, USAF ,WPAFB, Ohio Tim, Try typing t-Butyl Acetate (or its CAS No.: 540-88-5) in the Chemfinder Web site at : http://chemfinder.camsoft.com/ Try also HSDB (Hazardous Substances Data Bank) at : http://sis.nlm.nih.gov/sis1/ Denis Begin, M.Sc. Research Assistant University of Montreal Dept. of Occupational and ...
Abstract Cigarette smoking harms nearly every organ of the body and causes many diseases. The analysis of exhaled breath for exogenous and endogenous volatile organic compounds VOCs can provide fundamental information on active smoking and insight into the health damage that smoke is creating. Various exhaled VOCs have been reported as typical of...
South Coast AQMD is conducting comprehensive air pollution measurements near refineries and surrounding communities as part of the AB 617 and Rule 1180 programs. The Community Emissions Reduction Plan for the Wilmington/Carson/West Long Beach community has a measure to reduce NOx, SOx, VOCs and other associated toxics emissions from refineries by 50 percent between 2020 and 2030. To assess this target, there is a need to quantify and characterize fugitive VOC emissions near and around refineries in 2020 as well as to assess progress in the future once a baseline has been established. As part of Rule 1180, staff will be operating and maintaining a network of community air monitoring stations throughout the Basin. These actions are to reallocate up to $500,000 to Science & Technology Advancements FYs 2019-20 and 2020-21 Budgets, execute a contract, and approve the addition and deletion of Rule 1180 positions to perform this work. (No Committee Review) ...
The draft regulation is an interpretation of the European Construction Products Regulation regarding VOC emissions from construction products into indoor air. It is the fourth such national regulation after those in Belgium, in France and in Germany.
Trace volatile organic compounds (VOCs) are ubiquitous in air, exhaled breath, cigarette smoke and aerosol of electronic cigarettes. Some VOCs in air and smoke are toxic and some VOCs in exhaled breath are related to biochemical processes of specific diseases.
The global pearlescent pigment market is expected to reach USD 547.8 million by 2022, according to a new report by Grand View Research, Inc. Growing demand for high performance, high brilliance paints on account of expanding automotive & construction industries in emerging markets is expected to remain a key driving factor for the global market.. Shift in trend towards reducing VOC emissions and growing awareness regarding sustainability is also expected to act as a vital determinant for market growth. Developed markets are anticipated to face obstacles in the form of stringent regulatory norms, hampering market growth over the forecast period.. Browse Detail Report With TOC @ http://www.hexareports.com/report/pearlescent-pigment-market/details. Titanium dioxide (TiO2) coated mica pigment was the leading product segment with demand share exceeding 35% in 2014. High consumption rates of these pigments across automotive, construction and printing ink industries is expected to drive this segment ...
Epsilon dry disconnect coulings are designed to prevent chemical spills & reduce VOC emissions, particularly in the process facility & during transfer. RFQ!
Epsilon dry disconnect coulings are designed to prevent chemical spills & reduce VOC emissions, particularly in the process facility & during transfer. RFQ!
Chemical compound - Spectroscopy of organic compounds: Until the mid-20th century, most organic compounds were distinguished from one another largely on the basis of simple physical and chemical properties. Knowledge of these properties, however, yields only superficial clues about a compounds molecular structure, and the determination of that structure was a complicated process (for large molecules at least) that involved careful analysis of several reaction pathways. Chemists had no way to see what molecules looked like, because molecules are so small that no device such as a microscope could be developed that would give a complete image of a molecular structure. One technique, X-ray crystallography, can give
A compendium of all the volatile organic compounds (VOCs) emanating from the human body (the volatolome) is for the first time reported. 1840 VOCs have been ...
Analysis of Organic Compounds is a practical approach towards accurate identification of formula of a compound, percentage composition of the elements present in it and the functional group(s). It involves 3 important techniques. The first one is the use of chemical tests to identify the functional groups. The second aspect is the use of high resolution mass spectrometry to identify the mass and bonding positions. The third one is the use of IR spectroscopy to confirm the functional groups and other bonding modes through "fingerprinting".. High level research also includes the use of NMR spectroscopy for analysis of organic compounds.. Key Points:. ...
Article Rejection of trace organic compounds by RO/NF. The objective of this study is to develop a mechanistic understanding of the rejection of trace organic compounds by high-pressure membranes, based on an integrated framework of compound properti...
Christensen, S., Nemchenko, A., Borrego, E., Murray, I., Sobhy, I., Bozak, L., Erb, M., Robert, C., Vaughn, K., Göbel, C., Tumlinson, J., Feussner, I., Turlings, T., Engelberth, J., Nansen, C., Meeley, R., Kolomiets, M. (2013). The maize lipoxygenase, ZmLOX10, mediates green leaf volatile, jasmonate, and herbivore-induced plant volatile production for defense against insect attack. The Plant Journal, 74(1), 59-73. doi:10.1111/tpj.12101. [EXT367] ...
Introduction: In living things, organic compounds are present. Most common food contains the most abundant organic compounds of lipids, carbohydrates, and proteins. Lipids are used to store energy. They include fats oils and waxes. They contain mostly ...
Phthalate-Free Flexible Compounds Offer Improved Performance, No Increase In Cost ATLANTA--(BUSINESS WIRE)--Jun. 3, 2013-- Axiall Corporation (NYSE: AXLL) today announced the introduction of Aspire™ flexible vinyl compounds, the markets first phthalate-free, bio-based compounds offering improved performance at a price that is equal to its traditional non-sustainable counterparts. The Aspire family of compounds offers a more sustainable alternative for a variety of consumer and industrial end-use products that can benefit from a non-phthalate solution. Key sustainability credentials include: Bio-Based Plasticizers - Derived from renewable resources (non-petroleum-based feedstock) Organic-Based Stabilizers - Free of heavy metals Low Volatile Organic Compounds (VOCs) - Passes GREENGUARD Indoor Air Quality Certification and GREENGUARD Gold Children & Schools Certification High Renewable Carbon Content - Meets USDA BioPreferred Program requirements with greater than 25 percent renewable content ...
Various volatile compounds present in ripening figs were attractive to Carpophilus hemipterus, C. mutilatus, C.freemani, and C. lugubris.Field tests demonstrated that traps baited with a mixture of...
There are more than 5 million chemicals today, and roughly 100,000 of them are frequently used. Many of these chemicals are ultimately released into the environment and may cause adverse effects to ecosystems and human health. The purity of drinking water, measuring indoor air quality, responding to natural or man-made disasters, or identifying emerging contaminants is the subject that we are all exposed to. Volatile organic compounds (VOC) exist in water, soil, air or food. ...
PhotoCatalytic Oxidation PCO :. Carbon based organic molecules contaminants are effectively broken down by AirSteril PCO technology. Millions of highly reactive compounds are created every second and transmitted out of the AirSteril unit and acts as highly efficient catalyst for destroying odour, mold, airborne and surface bacteria, viruses, volatile organic compounds VOC such as formaldehyde, sterilizes the air and all Exposed surfaces 24/7 ...
When a tree is being defoliated by an insect herbivore, it will emit gaseous volatiles. Do these volatiles attract predators of the insect? Significantly so, it seems.
​As crop plants breathe through the pores in their leaves, they release an assortment of volatile organic compounds (VOCs) into the air. A new smartphone-connected device analyzes those chemicals within a matter of minutes, detecting and identifying any diseases that may be indicated.
A fish tank is a sealed system. With the exception of perhaps oxygen and carbon dioxide, which can enter and leave the system at the surface of the water, anything you put into the tank stays in the tank and nothing can get in unless you put it in. Put food in and you have added energy and nitrogenous waste (from the protein in the food). So the fish will grow (and so may plants) and the waste will build up. In a natural system such as a river or lake, this waste is washed away and broken down (recycled and reused by other organisms). In a tank it cannot go anywhere and you have to establish and maintain the natural waste disposal mechanisms to deal with it.. Solid waste will build up in the gravel or sand and in the filter. Left alone a sludge would eventually build up and begin to rot, releasing toxic volatile organic compounds (VOCs). To prevent this is easy. Simply stir up the gravel at each partial water change (more on that later) or better still, buy a gravel cleaner that cleans the ...
Scientific evidence shows that the microbiome has an impact on the mind. In fact it is to the extent that scientists call it the "second brain". Yet it may even be more accurate to say that it is the seat of the mind. The vagus nerve from the gut communicates 90% from the gut to the brain and only 10% from the brain back to the gut. And there are more microbe cells in the body than human DNA cells. Perhaps the brain is just a power plant/communications routing system which is used by the microbiome ...
Read the featured application note to learn about new methods for generating ultrapure water that is free from volatile organic compounds and is suitable for sensitive applications such as purge-and-trap GC/MS.
The detection limit for volatile organic compounds and volatile agents is from low ppb to the low ppm range depending on the analytical procedure, e.g. adsorbent enrichment (low ppb range) or on-line monitoring (very low ppm range) from ambient air. Operation has been simplified minimising training burdens and skill fade. The rugged system has been specially designed to be multirole and can be easily mounted in both military and civilian vehicles. ...
Bacterial infection Critically ill patients in hospitals can be severely affected by infections, which slow down their recovery or, in extreme cases, cause death. A recent international study found that the mortality rate in intensive care units rose from 11 in non-infected patients to 25 in those who had been infected. The majority of the...