Gas/particle Partitioning of Semi-volatile Organic Compounds to Model Atmospheric Particulate Material PDF Download
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Author: John Morse Elliot Storey
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 268
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Book Description
Author: John Morse Elliot Storey
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 268
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Book Description
Author: Douglas A. Lane
Publisher: CRC Press
ISBN: 1000124789
Category : Technology & Engineering
Languages : en
Pages : 415
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Book Description
It is becoming increasingly important to understand how and why semivolatile atmospheric pollutants partition between gas phase and particulate matter in the atmosphere. In this text the world's leading researchers in the field explain the significance of gas/particle ratios; physical and chemical parameters determining how semivolatiles partition in the atmosphere; how gas/particle ratio measurements are made; what artefacts occur during sampling; and novel new techniques and instruments for obtaining artefact-free results. Intended to be a reference book and a guide for those who study the gas/particle ratios of semivolatile atmospheric compounds. This book will be of interest to beginners in the field as well as those who have been involved in the field for many years and would like, in a single reference text, a comprehensive compendium of what is known about the theory and practice of gas/particle phase measurements.
Author: Cikui Liang
Publisher:
ISBN:
Category : Aerosols
Languages : en
Pages : 324
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Book Description
Author: Wentai Luo
Publisher:
ISBN:
Category : Gases
Languages : en
Pages : 566
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Book Description
Author: Lidia Morawska
Publisher: John Wiley & Sons
ISBN: 3527609202
Category : Science
Languages : en
Pages : 467
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Book Description
Covering the fundamentals of air-borne particles and settled dust in the indoor environment, this handy reference investigates: * relevant definitions and terminology, * characteristics, * sources, * sampling techniques and instrumentation, * exposure assessment, * monitoring methods. The result is a useful and comprehensive overview for chemists, physicists and biologists, postgraduate students, medical practitioners, occupational health professionals, building owners and managers, building, construction and air-conditioning engineers, architects, environmental lawyers, government and regulatory professionals.
Author: Claire Francis Fortenberry
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 327
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Book Description
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.
Author: James F. Pankow
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
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Book Description
Author: Donald Mackay
Publisher: CRC Press
ISBN: 9781566706872
Category : Science
Languages : en
Pages : 1000
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Book Description
Transport and transformation processes are key for determining how humans and other organisms are exposed to chemicals. These processes are largely controlled by the chemicals’ physical-chemical properties. This new edition of the Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals is a comprehensive series in four volumes that serves as a reference source for environmentally relevant physical-chemical property data of numerous groups of chemical substances. The handbook contains physical-chemical property data from peer-reviewed journals and other valuable sources on over 1200 chemicals of environmental concern. The handbook contains new data on the temperature dependence of selected physical-chemical properties, which allows scientists and engineers to perform better chemical assessments for climatic conditions outside the 20–25-degree range for which property values are generally reported. This second edition of the Handbook of Physical-Chemical Properties and Environmental Fate for Organic Chemicals is an essential reference for university libraries, regulatory agencies, consultants, and industry professionals, particularly those concerned with chemical synthesis, emissions, fate, persistence, long-range transport, bioaccumulation, exposure, and biological effects of chemicals in the environment. This resource is also available on CD-ROM
Author: Donald Mackay
Publisher: CRC Press
ISBN: 1420032542
Category : Science
Languages : en
Pages : 274
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Book Description
Completely revised and updated, Multimedia Environmental Models: The Fugacity Approach, Second Edition continues to provide simple techniques for calculating how chemicals behave in the environment, where they accumulate, how long they persist, and how this leads to human exposure. The book develops, describes, and illustrates the framework and pro
Author: Srinandini Parthasarathy
Publisher:
ISBN:
Category :
Languages : en
Pages : 121
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Book Description
Humans spend most of their time indoors, in residences and commercial buildings. In this thesis, I evaluate exposures to volatile (VOCs) and semivolatile organic compounds (SVOCs) in indoor environments. I use a combination of literature review and evaluation, mechanistic modeling, and skin-wipe collection and analysis to develop an understanding of the role of indoor air as an exposure medium for inhalation and passive dermal uptake of pollutants. This dissertation explores three related research topics on indoor environments and human exposures. In Chapter 2, I conduct a comprehensive review of reported measurements of pollutants found in commercial buildings. I used the literature review to estimate concentration ranges that can be compared to health-based exposure limits as basis for hazard assessment. I use the regulatory exposure limits set by government agencies to calculate hazard indices as the ratio of observed concentrations to regulatory standards. I also compare the odor and pungency thresholds of individual pollutants to observed concentrations to evaluate their potential to exceed odor thresholds. The hazard evaluation identifies the potential for health impacts at concentrations commonly found in commercial buildings. This analysis focuses exclusively on VOCs and SVOCs in commercial buildings and identified a limited set of pollutants that pose health concerns. I also characterize the selected pollutants in terms of the chemical properties that,affect partitioning to various indoor surfaces, and subsequently their fate and transport in indoor environments. Based on chemical properties and indoor fate, I grouped the pollutants into five groups. I use an hierarchical k-means analysis based on octanol-air partitioning coefficient, octanol-water partitioning coefficient, air-water partitioning coefficient, and molecular weight. The pollutants in each group are expected to behave similarly in indoor environments. In Chapter 3, I evaluate the role of buildings operation parameters such as ventilation and filtration in limiting exposures to pollutants originating from indoor and outdoor sources. I use a simple well-mixed-air model of an indoor space to study the impact of ventilation on concentrations of ozone, nitrogen dioxide, carbon monoxide, and radon. I employ a chemical-thermodynamics-(fugacity)-based mass balance model in conjunction with a particle mass balance to study the fate and transport of particulate matter, VOCs, and SVOCs. The fugacity mass balance model accounts for chemical partitioning among air, air-borne particles, and indoor surfaces. I ran the fugacity model with indoor and outdoor source of VOCs and SVOCs and indoor and outdoor sources of particulate matter. I evaluate the consequent inhalation exposures these sources with two outcome metrics, intake fraction (iF) for indoor sources and indoor/outdoor concentration ratio for outdoor sources. The exposure to particulate matter of indoor and outdoor origin was evaluated using the outcome metrics iF and the indoor proportion of outdoor particles (iPOP). The model evaluation shows that ventilation is most effective at controlling exposures to VOCs that have an indoor source. Filtration is seen to be effective at controlling exposures to particulate matter and SVOCs that partition preferentially onto particulate matter. In Chapter 4, I explore the role of indoor air in delivering SVOCs to human occupants through passive dermal uptake. I collected wipe samples from thirteen subjects who were randomly chosen. For each subject, I collected three sequential wipe samples from the forehead and one sample from the palm. I analyzed the samples for a suite of SVOCs and skin lipids (squalene and sapienic acid) in an analytical laboratory using gas chromatography and liquid chromatography. All forehead wipe samples contained SVOCs indicating that air to skin transfer of pollutants for passive dermal uptake could be a significant exposure pathway for SVOCs. Because skin lipid concentrations decrease with depth the quantitation of skin lipid concentrations from each wipe allowed me to estimate the depth of sampling by each skin wipe. This is the first study to quantitatively evaluate the depth of sampling by skin wipes. I use the experimental results together with a theoretical model to explore the potential role of skin as a passive sampler for short-term personal exposures, indoors. For this I develop a metric called the equivalent time of exposure (ETE) to study the usefulness of sequential skin wipe samples as a passive sampler. I used partitioning coefficients from air to skin surface, combined with a dynamic skin mass transport model, to study the theoretical transport of pollutant through the stratum corneum. I compare the modeled concentrations to measured concentrations, at comparable depths. The ETE is the amount of time to which the subject would have to be exposed to a constant air concentration to attain the observed skin-wipe concentration depth profile in the stratum corneum. Based on the ETE, I find that skin wipe samples could be indicative of exposures up to 6 hours prior to wipe sampling, depending on the diffusion coefficient of the pollutant. The overarching goal of this research is to evaluate the role of indoor air in mediating the transfer to human receptors of pollutants released indoors or brought indoors from outdoor sources. The indoor air mass controls the fate and transport of pollutants in indoor spaces, and the rate of delivery of pollutants for inhalation and dermal uptake. The research highlights the important role of air-to-surface and air-to-particle partitioning in facilitating or mitigating source-receptor relationships. The work illustrates future research opportunities for tracking the complex web of indoor/outdoor pathways that bring pollutants into the human environment and into the blood and other viable tissues of the human population.
