Download or read book Development of Novel Instrumentation and Methods to Investigate the Composition and Phase Partitioning of Semivolatile and Intermediately Volatile Organic Compounds in Atmospheric Organic Aerosol written by Claire Francis Fortenberry and published by . This book was released on 2020 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric particulate matter (PM) is ubiquitous in both indoor and outdoor air and is generally detrimental to human health. PM composed of particles with aerodynamic diameters less than 2.5 um (PM2.5) are related to adverse health outcomes including heart disease and respiratory disease. Fundamentally, particle physical properties such as size and hygroscopicity are dictated by chemical composition, which can be highly complex, particularly for organic aerosol (OA). In both outdoor and indoor air, OA is composed substantially of intermediately volatile and semivolatile organic compounds (I/SVOCs), which exist in both gas and particle phases under typical atmospheric conditions. The distribution of these compounds between the two phases can change rapidly depending on conditions like temperature, relative humidity, and concentrations of surrounding particles and gases. The chemical complexity and rapidly-changing dynamics of I/SVOCs in OA necessitates improved instrumentation to speciate complex mixtures of I/SVOCs in both gas and particle phases at fast time scales relative to phase partitioning dynamics.The Thermal desorption Aerosol Gas Chromatograph (TAG), which performs in-situ ambient collection and molecular-level speciation of organics at hourly time resolution, is uniquely suited to meet these challenges. The TAG system has been modified in various ways to collect and analyze different targeted molecules in both the gas and particle phases. In addition to speciated organics, the impactor-based collection and thermal desorption (ICTD) system developed for the original TAG features unique thermal decomposition data, which provides information on thermally labile organic and inorganic fragments. These data have been used in laboratory and field studies to evaluate different species not normally analyzable by gas chromatography. However, the ICTD cell is not suitable for gas-phase quantification.This dissertation addresses two major research themes: laboratory and field measurements to improve understanding of I/SVOCs in indoor and outdoor air, and development of improved I/SVOC measurement techniques. Within the first theme, atmospheric aging of I/SVOCs from biomass burning plumes was characterized in controlled laboratory studies with an oxidation flow reactor using molecular speciation and thermal decomposition data from the ICTD-TAG. I/SVOCs in indoor air were investigated under different natural ventilation (window opening) conditions using the ICTD-TAG in two field studies, and phase partitioning dynamics of indoor-measured I/SVOCs were examined in targeted experiments conducted in the field. Within the second theme, a denuder-based gas trap (GT) was developed and incorporated in parallel into the ICTD-TAG. Following initial GT testing in field studies, the design was modified and characterized through standard calibrations. Simple laboratory studies demonstrate that the GT-ICTD-TAG effectively measures changes in particle-phase fractions.
Download or read book Development and Testing of Sampling Methods for the Determination of Selected Semi Volatile Organic Components Distributed in Aerosols Between Gas and Particle Phase written by Dariusz Antkowiak and published by . This book was released on 2006 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Passive Samplers for Measuring Indoor Air Concentrations and Measurement of Physical and Chemical Properties of Semi Volatile Organic Compounds written by Joseph Ocheje Okeme and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Human exposure to semi-volatile organic compounds (SVOCs) including flame retardants (FRs) and plasticizers used in consumer products from indoor sources is a serious concern. These compounds are then advected to the outdoor environment which leads to regional and long-range transport and exposure to the ecosystem. This thesis aims to improve our understanding of exposure to selected SVOCs by developing tools, methods and providing data to facilitate exposure assessment particularly regarding indoor air. Three new passive air samplers (PAS), namely silicone rubber (polydimethylsiloxane, PDMS), styrene-divinylbenzene copolymer (XAD)-Pocket and XAD-PDMS were calibrated against an active air sampler and compared to the more popular polyurethane foam (PUF) PAS. Although the indoor sampling rates vary, we recommend from these studies a generic sampling rate of 1.7 m3 day-1dm-2 and 0.94 m3 day-1dm-2 for PDMS and PUF, respectively. The active air sampler was also used to assess the gas-particle distribution of the target compounds. The particle-phase partitioning fractions of SVOCs is a key determinant of their environmental behaviour and potential for exposure thus toxicity. A key finding here, is that some relatively volatile organophosphate ester FRs are present in the gas-phase where most published studies of active air sampling report them largely in the particle phase, indicating a sampling artifact. To improve chemical screening and modelling of the transport and fate, this thesis provides experimentally determined values of vapour pressures and octanol-air partition coefficients for over 50 SVOCs measured here using the well-established gas chromatography retention time method. Deployment of PDMS and PUF in residential homes gave comparable estimates of air concentrations for SVOCs in the gas-phase, although PUF was more able to capture compounds with higher fractions in the particulate phase. PDMS shows promise as a tool for estimating exposure to a wide range of SVOCs indoors, although its particle sampling efficiency warrants further work.
Download or read book Method Development For Concentration Measurements of SVOCs and Analysis of Ambient Samples written by Yasamin Hassani and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semi-volatile organic compounds (SVOCs) comprise a wide range of toxic pollutants in the atmosphere. Phenols, polycyclic aromatic hydrocarbons (PAHs) and n-alkanes are specific examples of SVOCs that are the focus of this project. SVOCs are compounds with intermediate vapour pressures and can exist in the atmosphere in both gas phase and in particulate matter (PM), which makes their quantification in the atmosphere challenging. Therefore, developing a well-characterized analytical technique for accurate concentration measurement of the selected classes of SVOCs is essential in order to gain more insight into their ambient yield and environmental fate. Recently, a new methodology that allows sampling and analysis of the total (gas phase and PM) concentration of SVOCs in the atmosphere has been developed and tested on a class of SVOCs, namely, nitrophenols (Busca, 2010; Moukhtar et al., 2011; Saccon et al., 2013). This method is based on a sorbent impregnated filter (SIF) technique using conventional high volume air samplers, extraction and analysis by GC-MS. In this project, the newly developed XAD-4TM SIF was modified, developed and tested to determine its suitability for ambient concentration measurements of other classes of SVOCs like PAHs and n-alkanes. The results of the method validation tests show that the XAD-4TM SIF technique can be used for quantitative measurements of PAHs and n-alkanes in the atmosphere. Atmospheric samples were collected in Toronto as well as in the Alberta Oil Sands region and analyzed using the modified analytical technique. Preliminary results obtained from the Oil Sands samples showed relatively high concentrations for the three classes of SVOCs, particularly in samples impacted by the plume suspected to originate from the Syncrude and/or Suncor mining and upgrading sites. The carbon preference index (CPI) values obtained for these Oil Sands samples also indicated a substantial anthropogenic impact, even for the samples that were not significantly influenced by nearby emissions from upgrading/refining facilities. The CPI values for some samples were also consistent with some biogenic impact. A comparison of the phase distribution measurements of the three classes of SVOCs demonstrated a systematic dependence between the phase partitioning and vapour pressure for all n-alkanes and most PAHs. However, most of the nitrophenols did not follow this pattern, consistent with findings reported by Facca (2013) and Saccon et al. (2013). Some PAHs with intermediate vapour pressures also did not follow the partitioning expected from their vapour pressure. This indicates that factors other than vapour pressure play a major role in the partitioning of these SVOCs in the atmosphere.
Download or read book Laboratory Study of Volatile Organic Compound Partitioning Vapor aqueous soil written by Alan Dole Hewitt and published by . This book was released on 1998 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of a Flow Through Sampler for Semi Volatile Organic Compounds in Air written by Hang Xiao and published by . This book was released on 2008 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the atmospheric fate and transport of semi-volatile organic compounds (SOCs) often requires the sampling of large volumes of air (>100 m3) in a relatively short period of time. Conventionally high-volume pumps are not suitable for remote areas without access to reliable network power. We have developed a flow through sampler for such situations. It consists of a horizontally-oriented flow-tube, that can collect gaseous and particle-bound SOCs from large volumes of air by turning into the wind and having the wind blow through a porous sampling medium such as polyurethane foam. Through both indoor and outdoor experiments, we quantified its air sampling rate (through battery operated anemometers inside and outside of the flow tube), its sampling efficiency (by theoretical plate number analysis of the break-though curves for PCBs, PAHs, OCPs and PBDEs), and its accuracy (by comparison of concentrations, time trends, temperature dependences and isomer ratios with those obtained by conventional high-volume sampling) under conditions of constant and variable meteorological conditions (wind speed, temperature). The flow-through sampler was deployed to monitor SOC concentrations at a remote Chinese research station located close to Nam Co Lake, Tibet. During the campaign, fifteen 1 month-long samples were taken, corresponding to sample volumes between 5,000 and 20,000 m3. Despite those large sample volumes, only HCB and HCHs experienced break-through, but application of frontal chromatograph theory allows the estimation of breakthrough-corrected air concentrations even for those relatively volatile SOCs. The pesticide levels at Nam Co are generally very low. Most pesticides had higher levels during summer, resulting in a strong temperature dependence. This is correlated with air mass origin across the Himalayas in the Gangetic plains of India and Bangladesh. The flow through sampler constitutes a feasible method for reliably and quantitatively collecting SOCs from large air volumes.
Download or read book A Diffusion Denuder for the Measurement of Semivolatile Organic Compounds in Ambient Air written by Mark Steven Krieger and published by . This book was released on 1993 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Application of a Flow through Sampler for Semi volatile Organic Compounds in Air written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: PhD.
Download or read book Cooperative Research and Development Agreement with Graseby Nutech Corporation written by and published by . This book was released on 1995 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improved Air Sampling Instrumentation and Methodologies for the Collection of Semivolatile Organic Compounds written by Jeffrey C. Wallace and published by . This book was released on 1995 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Methods for Analysis of Volatile Organic Compounds Present in the Liquid Phase Solid Phase and Adsorbed on Surfaces written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aerosol Science written by Ian Colbeck and published by John Wiley & Sons. This book was released on 2014-02-03 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: AEROSOL SCIENCE TECHNOLOGY AND APPLICATIONS Aerosols influence many areas of our daily life. They are at the core of environmental problems such as global warming, photochemical smog and poor air quality. They can also have diverse effects on human health, where exposure occurs in both outdoor and indoor environments. However, aerosols can have beneficial effects too; the delivery of drugs to the lungs, the delivery of fuels for combustion and the production of nanomaterials all rely on aerosols. Advances in particle measurement technologies have made it possible to take advantage of rapid changes in both particle size and concentration. Likewise, aerosols can now be produced in a controlled fashion. Reviewing many technological applications together with the current scientific status of aerosol modelling and measurements, this book includes: Satellite aerosol remote sensing The effects of aerosols on climate change Air pollution and health Pharmaceutical aerosols and pulmonary drug delivery Bioaerosols and hospital infections Particle emissions from vehicles The safety of emerging nanomaterials Radioactive aerosols: tracers of atmospheric processes With the importance of this topic brought to the public's attention after the eruption of the Icelandic volcano Eyjafjallajökull, this book provides a timely, concise and accessible overview of the many facets of aerosol science.
Download or read book A Method for Concentrating and Determining Trace Organic Compounds in the Atmosphere written by and published by . This book was released on 1972 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Determination of subpart-per-billion (sub-ppb) levels of volatile organic compounds in the atmosphere by flame ionization gas chromatography requires sample sizes of at least several hundred milliters of air. Cryogenic methods of concentrating trace compounds before analysis have the disadvantage of also concentrating large amounts of water, a serious problem in gas-liquid chromatography. A simple method was developed for sample collection and concentration using porous polymer adsorbants with the unique properties of high capacity for retention of organic compounds and minimal capacity for retention of water. This technique was used to determine sub-ppb levels of volatile organic compounds in a typical rural atmosphere. Probable sources of these organic compounds were vehicle exhaust, biological processes, natural gas leaks, and industrial chemicals.
Download or read book Quantitative Analysis of Volatile and Semivolatile Organic Compounds in Air with Solid Phase Microextraction written by Abir Khaled and published by . This book was released on 1999 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organic Indoor Air Pollutants written by Tunga Salthammer and published by John Wiley & Sons. This book was released on 2009-11-18 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the quality of indoor air ranking highly in our lives, this second, completely, revised edition now includes 12 completely new chapters addressing both chemical and analytical aspects of organic pollutants. Sources of indoor air pollutants, measurement and detection as well as evaluation are covered filling the gap in the literature caused by this topical subject. This book is divided into four clearly defined parts: measuring organic indoor pollutants, investigation concepts and quality guidelines, field studies, and emission studies. The authors cover physico-chemical fundamentals of organic pollutants, relevant definitions and terminology, emission sources, sampling techniques and instrumentation, exposure assessment as well as methods for control. Test methods and studies for various indoor environments are described, such as automobile interiors, museum environments, or rooms with air ventilation. Emission sources covered include household and consumer products as well as electronic devices and office equipment. The book is aimed at chemists, physicists, biologists, and medical doctors at universities and research facilities, in industry and environmental laboratories as well as regulative bodies.
Download or read book Development of Passive Air Samplers for Semivolatile Organic Compounds written by Michael E. Bartkow and published by . This book was released on 2004 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Volatile Analysis written by Hans F. Linskens and published by Springer Science & Business Media. This book was released on 1997-04-16 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book covers a vast array of methods for the analysis of volatile compounds exuded by plants. Some of these volatiles are of great commercial importance, including the aromas of wines and teas, and volatiles in fruits. Other volatiles such as essential oils can be useful for chemotaxonomic purposes, and a chapter on an emerging method, that of chemometric analysis of such data, is included. Isoprene and ammonia rarely find a place in analytical methods presented for plant materials, but methods for these volatiles are described in this book. The volatiles given off by flowers are also included, and in situ headspace analysis of these volatiles is described, a method of potential use for the study of insect-plant interactions.
