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Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms Using the Aerosol Modeling Testbed

Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms Using the Aerosol Modeling Testbed PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Book Description
This work investigated the formation and evolution of organic aerosols (OA) arising from anthropogenic and biogenic sources in a framework that combined state-of-the-science process and regional modeling, and their evaluation against advanced and emerging field measurements. Although OA are the dominant constituents of submicron particles, our understanding of their atmospheric lifecycle is limited, and current models fail to describe the observed amounts and properties of chemically formed secondary organic aerosols (SOA), leaving large uncertainties on the effects of SOA on climate. Our work has provided novel modeling constraints on sources, formation, aging and removal of SOA by investigating in particular (i) the contribution of trash burning emissions to OA levels in a megacity, (ii) the contribution of glyoxal to SOA formation in aqueous particles in California during CARES/CalNex and over the continental U.S., (iii) SOA formation and regional growth over a pine forest in Colorado and its sensitivity to anthropogenic NOx levels during BEACHON, and the sensitivity of SOA to (iv) the sunlight exposure during its atmospheric lifetime, and to (v) changes in solubility and removal of organic vapors in the urban plume (MILAGRO, Mexico City), and over the continental U.S. We have also developed a parameterization of water solubility for condensable organic gases produced from major anthropogenic and biogenic precursors based on explicit chemical modeling, and made it available to the wider community. This work used for the first time constraints from the explicit model GECKO-A to improve SOA representation in 3D regional models such as WRF-Chem.

Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms Using the Aerosol Modeling Testbed

Evaluation of New and Proposed Organic Aerosol Sources and Mechanisms Using the Aerosol Modeling Testbed PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Book Description
This work investigated the formation and evolution of organic aerosols (OA) arising from anthropogenic and biogenic sources in a framework that combined state-of-the-science process and regional modeling, and their evaluation against advanced and emerging field measurements. Although OA are the dominant constituents of submicron particles, our understanding of their atmospheric lifecycle is limited, and current models fail to describe the observed amounts and properties of chemically formed secondary organic aerosols (SOA), leaving large uncertainties on the effects of SOA on climate. Our work has provided novel modeling constraints on sources, formation, aging and removal of SOA by investigating in particular (i) the contribution of trash burning emissions to OA levels in a megacity, (ii) the contribution of glyoxal to SOA formation in aqueous particles in California during CARES/CalNex and over the continental U.S., (iii) SOA formation and regional growth over a pine forest in Colorado and its sensitivity to anthropogenic NOx levels during BEACHON, and the sensitivity of SOA to (iv) the sunlight exposure during its atmospheric lifetime, and to (v) changes in solubility and removal of organic vapors in the urban plume (MILAGRO, Mexico City), and over the continental U.S. We have also developed a parameterization of water solubility for condensable organic gases produced from major anthropogenic and biogenic precursors based on explicit chemical modeling, and made it available to the wider community. This work used for the first time constraints from the explicit model GECKO-A to improve SOA representation in 3D regional models such as WRF-Chem.

Aerosols in Atmospheric Chemistry

Aerosols in Atmospheric Chemistry PDF Author: Yue Zhang
Publisher: American Chemical Society
ISBN: 0841299293
Category : Science
Languages : en
Pages : 176

Book Description
The uncertainties in the aerosol effects on radiative forcing limit our knowledge of climate change, presenting us with an important research challenge. Aerosols in Atmospheric Chemistry introduces basic concepts about the characterization, formation, and impacts of ambient aerosol particles as an introduction to graduate students new to the field. Each chapter also provides an up-to-date synopsis of the latest knowledge of aerosol particles in atmospheric chemistry.

Toxicity of Atmospheric Aerosols: Methodologies & Assays

Toxicity of Atmospheric Aerosols: Methodologies & Assays PDF Author: Fobang Liu
Publisher: American Chemical Society
ISBN: 0841299811
Category : Science
Languages : en
Pages : 182

Book Description
Atmospheric aerosols, or particulate matter (PM), are liquid or solid particles suspended in the air. Exposure to ambient PM is associated with multiple diseases and accounts for millions of premature deaths today. Although recognized as an important public health problem, PM’s toxicity and toxicological mechanisms are yet to be understood. Various methodologies and assays (i.e., procedures to determine the composition, quantity, or quality of a substance or a mixture) have been developed or employed to understand the components and characteristics of PM that best determine its toxicity. Efforts have also been spent to study the mechanisms of cellular signaling, stress, response, and physiological change, as well as complex multi-tissue effects upon PM exposure. These assays are diverse, spanning from in vitro acellular assays (i.e., chemical assays) to in vitro cellular and in vivo assays. Given that various methodologies and assays have been developed or employed, this digital primer aims to introduce the methodologies and fundamental principles used to study atmospheric aerosols’ toxicity and emerging new techniques. A comprehensive literature review of the scientific findings using these methodologies and assays is not the focus of this primer. The target audiences are senior undergraduates or beginning graduate students unfamiliar with aerosol science and toxicity measurements. An introductory overview of atmospheric aerosols and the motivations to study their toxicity before a detailed discussion of methodologies and assays in the toxicity research of atmospheric aerosols is provided. Beyond this, Toxicity of Atmospheric Aerosols: Methodologies & Assays serves as an assembly of the various methodologies and assays used in the toxicity research of atmospheric aerosols, saving readers time compared to searching from scattered resources.

Determination of Secondary Organic Aerosol Sources, Precursors, and Properties Using Novel Measurement and Modeling Techniques

Determination of Secondary Organic Aerosol Sources, Precursors, and Properties Using Novel Measurement and Modeling Techniques PDF Author: Giulia Stefenelli
Publisher:
ISBN:
Category :
Languages : en
Pages :

Book Description


Establishing Chemical Mechanisms and Estimating Phase State of Secondary Organic Aerosol From Atmospherically Relevant Organic Precursors

Establishing Chemical Mechanisms and Estimating Phase State of Secondary Organic Aerosol From Atmospherically Relevant Organic Precursors PDF Author: Shashank Jain
Publisher:
ISBN:
Category :
Languages : en
Pages : 352

Book Description
Organic aerosol (OA) is a ubiquitous component of atmospheric particulate that influences both human health and global climate. A large fraction of OA is secondary in nature (SOA), being produced by oxidation of volatile organic compounds (VOCs) emitted by biogenic and anthropogenic sources. Despite the integral role of SOA in atmospheric processes, there remains a limited scientific understanding of the chemical and physical changes induced in SOA as it ages in the atmosphere. This thesis describes work done to increase the knowledge of processes and properties of atmospherically relevant SOA. In the work presented in this thesis, I have worked on improving an existing innovative, soft ionization aerosol mass spectrometer and utilized it to establish chemical mechanisms for oxidation of atmospherically relevant organic precursors (i.e., Green Leaf Volatiles). I discovered that SOA formation from cis-3-hexen-1-ol is dominated by oligomer and higher molecular weight products, whereas the acetate functionality in cis-3-hexenylacetate inhibited oligomer formation, resulting in SOA that is dominated by low molecular weight products. One of the most important factors contributing to uncertainties in our estimations of SOA mass in the atmosphere, remains our basic assumption that atmospheric SOA is liquid-like, which we have found to be untrue. Hence, I developed a methodology to estimate the phase state of SOA and identified new parameters that can have significant influence on the phase state of atmospheric aerosol. This simplified method eliminates the need for a Scanning Mobility Particle Sizer (SMPS) and directly measures Bounce Factor (BF) of polydisperse SOA using only one multi-stage cascade Electrostatic Low Pressure Impactor (ELPI). The novel method allows for the real time determination of SOA phase state, permitting studies of the relationship between SOA phase, oxidative formation and chemical aging in the atmosphere. I demonstrated that SOA mass loading (CSOA) influences the phase state significantly. Results show that under nominally identical conditions, the maximum BF decreases by approximately 30% at higher CSOA and suggests that extrapolation of experiments not conducted at atmospherically relevant SOA levels to simulate the chemical properties may not yield results that are relevant to our natural environment. My work has provided a better understanding of the mechanisms of aerosol formation at atmospheric concentrations, which is necessary to understand its physical properties. This improved understanding is fundamental to accurately model aerosol formation in the atmosphere, and subsequently evaluate their large-scale effect on human health and environment.

Modeling Secondary Organic Aerosol Formation from Emissions of Combustion Sources

Modeling Secondary Organic Aerosol Formation from Emissions of Combustion Sources PDF Author: Shantanu Hemant Jathar
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

Book Description


Climate Intervention

Climate Intervention PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309314852
Category : Science
Languages : en
Pages : 276

Book Description
The growing problem of changing environmental conditions caused by climate destabilization is well recognized as one of the defining issues of our time. The root problem is greenhouse gas emissions, and the fundamental solution is curbing those emissions. Climate geoengineering has often been considered to be a "last-ditch" response to climate change, to be used only if climate change damage should produce extreme hardship. Although the likelihood of eventually needing to resort to these efforts grows with every year of inaction on emissions control, there is a lack of information on these ways of potentially intervening in the climate system. As one of a two-book report, this volume of Climate Intervention discusses albedo modification - changing the fraction of incoming solar radiation that reaches the surface. This approach would deliberately modify the energy budget of Earth to produce a cooling designed to compensate for some of the effects of warming associated with greenhouse gas increases. The prospect of large-scale albedo modification raises political and governance issues at national and global levels, as well as ethical concerns. Climate Intervention: Reflecting Sunlight to Cool Earth discusses some of the social, political, and legal issues surrounding these proposed techniques. It is far easier to modify Earth's albedo than to determine whether it should be done or what the consequences might be of such an action. One serious concern is that such an action could be unilaterally undertaken by a small nation or smaller entity for its own benefit without international sanction and regardless of international consequences. Transparency in discussing this subject is critical. In the spirit of that transparency, Climate Intervention: Reflecting Sunlight to Cool Earth was based on peer-reviewed literature and the judgments of the authoring committee; no new research was done as part of this study and all data and information used are from entirely open sources. By helping to bring light to this topic area, this book will help leaders to be far more knowledgeable about the consequences of albedo modification approaches before they face a decision whether or not to use them.

Mixed-Phase Clouds

Mixed-Phase Clouds PDF Author: Constantin Andronache
Publisher: Elsevier
ISBN: 012810550X
Category : Science
Languages : en
Pages : 302

Book Description
Mixed-Phase Clouds: Observations and Modeling presents advanced research topics on mixed-phase clouds. As the societal impacts of extreme weather and its forecasting grow, there is a continuous need to refine atmospheric observations, techniques and numerical models. Understanding the role of clouds in the atmosphere is increasingly vital for current applications, such as prediction and prevention of aircraft icing, weather modification, and the assessment of the effects of cloud phase partition in climate models. This book provides the essential information needed to address these problems with a focus on current observations, simulations and applications. Provides in-depth knowledge and simulation of mixed-phase clouds over many regions of Earth, explaining their role in weather and climate Features current research examples and case studies, including those on advanced research methods from authors with experience in both academia and the industry Discusses the latest advances in this subject area, providing the reader with access to best practices for remote sensing and numerical modeling

Assessment of Intraseasonal to Interannual Climate Prediction and Predictability

Assessment of Intraseasonal to Interannual Climate Prediction and Predictability PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 030915183X
Category : Science
Languages : en
Pages : 192

Book Description
More accurate forecasts of climate conditions over time periods of weeks to a few years could help people plan agricultural activities, mitigate drought, and manage energy resources, amongst other activities; however, current forecast systems have limited ability on these time- scales. Models for such climate forecasts must take into account complex interactions among the ocean, atmosphere, and land surface. Such processes can be difficult to represent realistically. To improve the quality of forecasts, this book makes recommendations about the development of the tools used in forecasting and about specific research goals for improving understanding of sources of predictability. To improve the accessibility of these forecasts to decision-makers and researchers, this book also suggests best practices to improve how forecasts are made and disseminated.

Nucleation of Water

Nucleation of Water PDF Author: Ari Laaksonen
Publisher: Elsevier
ISBN: 0128143223
Category : Science
Languages : en
Pages : 296

Book Description
Nucleation of Water: From Fundamental Science to Atmospheric and Additional Applications provides a comprehensive accounting of the current state-of-the-art regarding the nucleation of water. It covers vapor-liquid, liquid-vapor, liquid-ice and vapor-ice transitions and describes basic kinetic and thermodynamic concepts in a manner understandable to researchers working on specific applications. The main focus of the book lies in atmospheric phenomena, but it also describes engineering and biological applications. Bubble nucleation, although not of major atmospheric relevance, is included for completeness. This book presents a single, go-to resource that will help readers understand the breadth and depth of nucleation, both in theory and in real-world examples. Offers a single, comprehensive work on water nucleation, including cutting- edge research on ice, cloud and bubble nucleation Written primarily for atmospheric scientists, but it also presents the theories in such a way that researchers in other disciplines will find it useful Written by one of the world’s foremost experts on ice nucleation