Download or read book Characterization of the Light Absorbing Properties and Source Apportionment of Atmospheric Brown Carbon written by Nivedita Krishna Kumar and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Urban Aerosols and Their Impacts written by Jeffrey S. Gaffney and published by . This book was released on 2006 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Urban aerosols have been identified as important species of concern due to their potential health and environmental impacts. This symposium series book will describe the basic chemistry and physics determining the impacts of aerosol species and will highlight the research results from the measurements that were taken following the collapse of the World Trade Center (WTC) on 9/11/01. The WTC tragedy led to the release of millions of pounds of debris aside from the structural steel, part of which was widely dissipated as aerosols and particulates in the debris cloud over lower Manhattan. Additionally, continuing fires under the debris led to the release of fine combustion related aerosols for a considerable time period in this urban environment. Held during the week of the second anniversary of the WTC tragedy in NYC, the symposium book will describe various aspects of the event, aerosol and gas exposures, and the related impacts of these aerosols. The book contributions will highlight efforts work from atmospheric chemists, meteorologists, health workers, and biologists for a timely compilation of what is known and not known about the composition and transport of tropospheric aerosols in urban environs, particularly those from the WTC collapse. Particular interest is in the acute and chronic environmental effects of these aerosols as they impact human health. Chapters included in the book will also address aerosol lifetimes, aerosol transport and removal processes, acute and chronic health effects to fine aerosol and particulate exposures, and the environmental impacts of aerosols.
Download or read book Toward Improved Understanding of Black and Brown Carbon Radiative Impacts Over South Asia written by Apoorva Pandey and published by . This book was released on 2019 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols directly affect the Earth's radiative budget by absorbing and scattering solar radiation. Carbonaceous aerosols constitute 20-90% of the global aerosol mass burden and are recognized by the Intergovernmental Panel on Climate Change as important drivers of direct radiative forcing (DRF). Aerosol radiative impacts have been implicated in regional atmospheric warming in South Asia: changing Indian monsoon patterns, and accelerating melting of the Himalayan glaciers. There are systematic global discrepancies between estimates of aerosol absorption optical depths derived from observations and those from climate models. Over South Asia, models predict six times lower aerosol absorption than ground-based observations, leading to a low bias in modeled DRF. To resolve this bias, there is a need to (1) account for relevant emission source types, and associated emission rates, and (2) constrain aerosol optical properties: mass absorption cross-sections (MAC), single scattering albedo (SSA) and scattering directionality parameters (asymmetry parameter or upscatter fraction). To that end, two broad classes of light absorbing carbonaceous aerosols need to be separately dealt with: black carbon (BC) and brown carbon (BrC).BC is known to strongly absorb visible solar radiation and its optical properties have been characterized using both direct measurements and optical models. BC aerosols exhibit aggregate morphologies, with fractal dimensions of 1.8 and 2.6 for fresh and aged particles, respectively. As a simplification, current climate models usually approximate BC aerosols as volume-equivalent spheres and use analytical solutions (known as the Lorenz-Mie theory) of Maxwell's equations for estimating their optical properties. Recent modeling studies employed the numerically-exact superposition transition-matrix method to compute optical cross-sections of fractal aggregates of varying sizes and fractal dimensions. These studies highlight the effect of morphology on BC optical behavior soot but their findings (expressed in terms of fractal properties) cannot be used directly by aerosol experimentalists and climate modelers. Exploiting the theoretical bases of aerosol sizing techniques, I determined empirical relationships between numerically-exact optical properties of fractal BC particles and their equivalent diameters, that can be measured by common aerosol instrumentation. In a related study, I reported improved relationships between scattering directionality parameters of BC aggregates, and compared them with the canonical equations which did not allow for treatment of particle morphology.The second branch of my thesis is concerned with light absorbing organic carbon (OC). OC is conventionally modeled as purely light scattering in radiative transfer calculations. However, this approach has been challenged by mounting observational evidence of a class of OC aerosols exhibiting strong absorption in the near ultra-violet wavelengths and little to no absorption in the near-infrared region. This wavelength dependence of absorption leads to a brownish appearance, hence the name brown carbon. Absorption properties of BrC depend on fuel properties and combustion phase (flaming/smoldering): their observed values are source-specific, spanning an order of magnitude in literature. The focus of this part of my research is on the largest source of OC emissions in South Asia: household biomass cookstoves. I conducted a field study in a household in central India in December 2015 and developed a dataset of emission rates for commonly used biomass fuels from various regions of India, which showed that (1) laboratory cookstove tests underestimated particulate mass emission factors by 2-4 times and (2) cookstove aerosol emissions were dominated by thermally stable OC, which is linked with stronger light absorption than volatile OC.To constrain the MAC values for cookstove OC emissions, I performed optical (transmission and reflection) measurements on filter samples of aerosols collected during the field study. Filter optical measurements are associated with artifacts arising from the interaction of the filter medium with light. Through a laboratory study of a wide variety of combustion aerosols, I developed correction schemes for estimating aerosol-phase light absorption from filter-based measurements. This aided the estimation of absorption characteristics of cookstove particulate emissions and their OC components. We found that light absorbing OC contributes roughly as much as BC to total absorption cross-sections of cookstove emissions at 550 nm wavelength, enhancing their direct forcing efficiency. We proposed values for key absorption characteristics of cookstove OC emissions for use within climate impact assessment and mitigation efforts.
Download or read book Modern Molecular Photochemistry written by Nicholas J. Turro and published by University Science Books. This book was released on 1991 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last two decades the photochemistry of organic molecules has grown into an important and pervasive branch of organic chemistry. In Modern Molecular Photochemistry, the author brings students up to date with the advances in this field - the development of the theory of photoreactions, the utilization of photoreactions in synthetic sequences, and the advancement of powerful laser techniques to study the mechanisms of photoreactions.
Download or read book Carbonaceous Aerosol written by András Gelencsér and published by Springer Science & Business Media. This book was released on 2007-09-28 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concept of carbonaceous aerosol has only recently emerged from atmospheric pollution studies; even standard nomenclature and terminology are still unsettled. This monograph is the first to offer comprehensive coverage of the nature and atmospheric role of carbonaceous aerosol particles. Atmospheric chemists, physicists, meteorologists, and modellers will find this a thought-inspiring and sometimes provocative overview of all global phenomena affected by or related to carbonaceous aerosol.
Download or read book Characterizing the Climate Impacts of Brown Carbon written by Lynn M. Russell and published by . This book was released on 2019 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lamto written by Luc Abbadie and published by Springer Science & Business Media. This book was released on 2006-11-22 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesizing 40 years of ongoing ecological research, this book examines the structure, function, and dynamics of the Lamto humid savanna. From the history of the Lamto ecology station, to an overview of enivronmental conditions of the site, and examining the integrative view of energy and nutrient fluxes relative to the dynamics of the region's vegetation, this exacting work is as unique and treasured as Lamto itself.
Download or read book Glaciers of the Himalayas written by Muthukumara Mani and published by World Bank Publications. This book was released on 2021-07-16 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: Melting glaciers and the loss of seasonal snow pose significant risks to the stability of water resources in South Asia. The 55,000 glaciers in the Himalaya, Karakoram, and Hindu Kush (HKHK) mountain ranges store more freshwater than any region outside of the North and South Poles. Their ice reserves feed into three major river basins in South Asia—the Indus, Ganges, and Brahmaputra—that are home to 750 million people. One major regional driver of the accelerating glacier melt is climate change, which is altering the patterns of temperature and precipitation. A second driver may be deposits of anthropogenic black carbon (BC), which increase the glaciers’ absorption of solar radiation and raise air temperatures. BC is generated by human activity both inside and outside of South Asia, and policy actions taken by the South Asian countries themselves may meaningfully reduce it. Glaciers of the Himalayas: Climate Change, Black Carbon, and Regional Resilience investigates the extent to which the BC reduction policies of South Asian countries may affect glacier formation and melt within the context of a changing global climate. It assesses the relative impact of each source of black carbon on snow and glacier dynamics. The authors simulate how BC emissions interact with projected climate scenarios. They also estimate the extent to which these glacial processes affect water resources in downstream areas of these river basins and present scenarios until 2040. Their policy recommendations include the following: Full implementation of current BC emissions policies can significantly reduce BC deposition in the region; additional reductions can be realized by enacting and implementing new policies that are economically and technically feasible. Improving the efficiency of brick kilns could be key to managing BC, and modest up-front investments could pay off quickly. Cleaner cookstoves and cleaner fuels can help to reduce BC and improve local air quality. Improving institutions for basin-based water management and using price signals are essential elements of more efficient water management. Careful management of hydropower and storage resources will require developers to factor in changing water flows and consider planning for large storage projects to stabilize water availability. Regional cooperation and the exchange of information can be an effective transboundary solution, helping countries to manage glaciers and related natural assets collaboratively. New policies are needed to reverse trends like the melting of glaciers. Success will require an active, agile cooperation between researchers and policy makers. To support an open dialogue, the model developed and used in this book is an open-source, state-of-the-art model that is available for others to use and improve on.
Download or read book Optical and Physicochemical Properties of Atmospherically Processed Brown Carbon Using Novel First principle Instrumentation written by Benjamin Jeffrey Sumlin and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric processing of brown carbon (BrC) -- a class of spherical, internally-mixed, light-absorbing organic aerosol -- emitted from smoldering biomass combustion is an understudied phenomenon with implications for climate science, air quality models, and satellite retrieval algorithms. BrC aerosols have received significant attention as a strong contributor to atmospheric light absorption in the shorter visible wavelengths and a driver of UV photochemistry. Their complex refractive indices (m=n+ik), size distributions, and carbon oxidation states dictate their optical properties, atmospheric residence times, and chemical interactions, respectively. There is currently a gap in our understanding of these fundamental particle properties and their evolution with atmospheric processing. Long-range transport and oxidation by O3, OH, and other atmospheric oxidants, as well as exposure to UV light present significant challenges when parameterizing these complex processes.This dissertation is broadly divided into three parts. The first part is a series of laboratory studies and the development of novel mathematical tools to provide a foundational understanding of chemical, physical, and optical properties of BrC aerosol and their evolution upon simulated atmospheric aging. The properties of primary BrC were studied as functions of moisture content, fuel source depth, geographic origin, and fuel packing density. No clear functionality in moisture content, source depth, or geographic origin were observed, however, the fuel packing density was found to have a significant impact on the resulting BrC optical properties. Additionally, the morphology and internal structure of BrC was studied using a centrifugal particle mass analyzer, and the long-standing assumption that BrC is spherical and homogeneous was rigorously verified. This result justifies the application of a new Mie Theory inversion algorithm to obtain the aerosol complex refractive index from laboratory measurements, which serves as an important input parameter in climate models and atmospheric remote sensing. The second part identifies the need for compact, robust, high-sensitivity aerosol instrumentation suitable for laboratory or field studies, and communicates the design, construction, and revision of a new multiwavelength integrated photoacoustic-nephelometer (MIPN). This new instrument is a field-portable instrument that directly measures the aerosol absorption and scattering coefficients at four wavelengths. The final part of this dissertation brings closure to the insights gained in laboratory studies by applying the MIPN to a series of real-world wildfires during FIREX-AQ, a large multiagency field campaign that took place in 2019. Daytime (OH-driven) and nighttime (NO3-driven) oxidation was performed on biomass burning aerosol using a Potential Aerosol Mass reactor aboard the Aerodyne Mobile Laboratory as it sampled wildfire events in Arizona and Oregon. The knowledge gained during these studies will help inform more accurate climate models and satellite remote sensing algorithms to better attribute the effects of atmospherically-processed BrC to global radiative transfer and climate change.
Download or read book Particulate Carbon written by George T. Wolff and published by Springer. This book was released on 2012-04-06 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the papers and discussions from the symposium, "PARTICU LATE CARBON: Atmospheric Life Cycle," held at the General Motors Research Laboratories on October 13-14, 1980. This symposium, which focused on atmospheric particulate elemental carbon, or soot, was the twenty-fifth in this series sponsored by the General Motors Research Laboratories. The present symposium volume contains discussions of the following aspects of particulate elemental carbon (EC): the atmos pheric life cycle of EC including sources, sinks, and transport processes, the role of EC in atmospheric chemistry and optics, the possible role of EC in altering climate, and measurement techniques as well as ambient concentrations in urban, rural, and remote areas. Previous symposia have covered a wide range of scientific and engineering subjects. Topics are selected because they are new or represent rapidly changing fields and are of significant technical importance. It is ironic that the study of particulate elemental carbon or soot should meet the above criteria for selection because soot, especially from coal and wood combustion, has been a recognized air pollutant for centuries. However, since the 1950s, when intense efforts to study air pollution were initiated, to until a few years ago, the role of elemental carbon in the atmosphere was largely ignored. The major reason for this was the lack of a suitable measurement technique.
Download or read book Global Sources of Local Pollution written by National Research Council and published by National Academies Press. This book was released on 2010-02-15 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in air pollution monitoring and modeling capabilities have made it possible to show that air pollution can be transported long distances and that adverse impacts of emitted pollutants cannot be confined to one country or even one continent. Pollutants from traffic, cooking stoves, and factories emitted half a world away can make the air we inhale today more hazardous for our health. The relative importance of this "imported" pollution is likely to increase, as emissions in developing countries grow, and air quality standards in industrial countries are tightened. Global Sources of Local Pollution examines the impact of the long-range transport of four key air pollutants (ozone, particulate matter, mercury, and persistent organic pollutants) on air quality and pollutant deposition in the United States. It also explores the environmental impacts of U.S. emissions on other parts of the world. The book recommends that the United States work with the international community to develop an integrated system for determining pollution sources and impacts and to design effective response strategies. This book will be useful to international, federal, state, and local policy makers responsible for understanding and managing air pollution and its impacts on human health and well-being.
Download or read book Chemical Characterization and Optical Properties of Brown Carbon Aerosol written by Feng Jiang and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Aerosols written by Claudio Tomasi and published by John Wiley & Sons. This book was released on 2017-03-20 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ein Blick auf die morphologischen, physikalischen und chemischen Eigenschaften von Aerosolen aus den unterschiedlichsten natürlichen und anthropogenen Quellen trägt zum besseren Verständnis der Rolle bei, die Aerosolpartikel bei der Streuung und Absorption kurz- und langwelliger Strahlung spielen. Dieses Fachbuch bietet Informationen, die sonst schwer zu finden sind, und vermittelt ausführlich die Kenntnisse, die erforderlich sind, um die mikrophysikalischen, chemischen und Strahlungsparameter zu charakterisieren, die bei der Wechselwirkung von Sonnen- und Erdstrahlen so überaus wichtig sind. Besonderes Augenmerk liegt auf den indirekten Auswirkungen von Aerosolen auf das Klima im Rahmen des komplexen Systems aus Aerosolen, Wolken und der Atmosphäre. Auch geht es vorrangig um die Wirkungen natürlicher und anthropogener Aerosole auf die Luftqualität und die Umwelt, auf die menschliche Gesundheit und unser kulturelles Erbe. Mit einem durchgängig lösungsorientierten Ansatz werden nicht nur die Probleme und Gefahren dieser Aerosole behandelt, sondern auch praktikable Lösungswege aufgezeigt.
Download or read book Models for the Aerosols of the Lower Atmosphere and the Effects of Humidity Variations on Their Optical Properties written by Eric P. Shettle and published by . This book was released on 1979 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol models have been developed for the lower atmosphere. These models are representative of conditions found in rural, urban, and maritime air masses. The changes in the aerosol properties with variations in the relative humidity are discussed. To describe the aerosol optical properties in the extreme of 100 percent relative humidity, several fog models are presented. For each model the coefficients for extinction, scattering, and absorption, the angular scattering distribution, and other optical parameters have been computed for wavelengths between 0.2 and 40 microns. These aerosol models are presented together with a review of their experimental basis. The optical properties of these models are discussed and some comparisons of the model with experimental measurements are presented.
Download or read book Multiphase Environmental Chemistry in the Atmosphere written by Sherri W. Hunt and published by ACS Symposium. This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights new cross-disciplinary advances in aerosol chemistry that involve more than one phase, for example, unique chemical processes occurring on gas-solid and liquid-solid interfaces.
Download or read book Climate Change Signals and Response written by Chandra Venkataraman and published by Springer. This book was released on 2018-07-06 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a synthesis of research findings, in terms of strategic knowledge outcomes regarding emergence of recent regional climate signals, implications for impacts assessment, and mitigation and adaptation response, relevant in the Indian context. The first part discusses evidence of climate change and its underlying scientific processes across India, chiefly focusing on impacts that are already visible and attributable to anthropogenic activities. The latter part deals with the responses to climate change, highlighting the mitigation and adaptation strategies in various sectors and communities. The book presents a concise interpretation, distilling practical recommendations and policy prescriptions at national and sub-national levels. It serves as a reference point for understanding scientific advances and persisting uncertainty, future vulnerability and response capacity of interlinked human and natural systems, pertaining to India. It is an excellent resource for policy makers and industry watchers in addition to the research fraternity.
Download or read book Investigative Strategies for Lead Source Attribution at Superfund Sites Associated with Mining Activities written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2017-12-01 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Superfund program of the US Environmental Protection Agency (EPA) was created in the 1980s to address human-health and environmental risks posed by abandoned or uncontrolled hazardous-waste sites. Identification of Superfund sites and their remediation is an expensive multistep process. As part of this process, EPA attempts to identify parties that are responsible for the contamination and thus financially responsible for remediation. Identification of potentially responsible parties is complicated because Superfund sites can have a long history of use and involve contaminants that can have many sources. Such is often the case for mining sites that involve metal contamination; metals occur naturally in the environment, they can be contaminants in the wastes generated at or released from the sites, and they can be used in consumer products, which can degrade and release the metals back to the environment. This report examines the extent to which various sources contribute to environmental lead contamination at Superfund sites that are near lead-mining areas and focuses on sources that contribute to lead contamination at sites near the Southeast Missouri Lead Mining District. It recommends potential improvements in approaches used for assessing sources of lead contamination at or near Superfund sites.
