Atmospheric Transformation of Polycyclic Aromatic Compounds PDF Download

Author: Sujan Fernando
Publisher:
ISBN:
Category :
Languages : en
Pages : 276

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Author: Antonius Indarto
Publisher: Universal-Publishers
ISBN: 1599423340
Category :
Languages : en
Pages :

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Book Description
Polycyclic Aromatic Hydrocarbons (PAHs) and soot share the same origin (incomplete combustion or pyrolysis) and nature, namely structural and electronic features. The purpose of the research work discussed in this thesis is to offer a theoretical contribution to elucidate some aspects of PAH and soot particle formation. The interest in carrying out such a work lies on one hand in the ubiquitous presence of both species in the environment, on the other hand on the concern for their impact on both human health, specifically involving the respiratory system, and climate, in particular as regards global warming. Thus, a better knowledge on the formation mechanisms of PAHs and soot could then help the efforts to reduce their concentration in our atmosphere. Since the formation mechanisms still presents unclear aspects, the suggestions and indications which can be offered by a theoretical study come out to be complementary to the large amount of experimental data collected so far. In setting up models aimed to mimic what happens in real pyrolysis or combustion situations, we have exploited the fact that PAHs and soot share as a common trait the presence of condensed unsaturated cycles (whose aromatic character can be variable). Thus, though types of soot of different origin will exhibit, on a larger scale, a variety of structural traits, we have chosen an assortment of PAH-like models to study different processes, together with other smaller unsaturated closed and open shell species that are known to play a role in the synthesis course. A preliminary phase of the study was aimed to assess which computational level could be both dependable and affordable to investigate the growth of a PAH-like radical when it is adsorbed onto soot platelets (particle phase). Then the Bittner-Howard variant of the widely accepted Hydrogen Abstraction Acetylene Addition (HACA) growth mechanism has been explored by Density Functional Theory (DFT) at the level mentioned above, both in the gas and particle phases, and over a wide range of temperatures. A parallel mechanism, differing from HACA, based on polyynes and characterized by the proliferation of radical centers, has also been studied for a variety of models at a multiconfigurational theory level. To the end, we have explored several reaction pathways starting from the addition of the propargyl radical to butadiyne.

Author:
Publisher: National Academies Press
ISBN:
Category : Air
Languages : en
Pages : 482

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Author:
Publisher:
ISBN:
Category : Polycyclic aromatic hydrocarbons
Languages : en
Pages : 500

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Author: Narumol Jariyasopit
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 192

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The trans-Pacific atmospheric transport of particulate matter (PM)-bound polycyclic aromatic hydrocarbons (PAHs) to remote sites in western North America has been well documented and has triggered research questions regarding to atmospheric transformation of PM-bound PAHs and the potential impacts on human health from their inhalation exposure. In this dissertation, field measurements, theoretical studies, laboratory experiments, and mutagenicity studies were used to begin the address the questions as to whether PM-bound PAHs undergo atmospheric transformation into mutagenic nitro-PAHs (NPAHs) during trans-Pacific atmospheric transport. PM extracts were tested in the Salmonella mutagenicity assay, using Salmonella typhimurium strain TA98 (with and without metabolic activation), to determine the mutagenic activities in relation to the chemical composition of the extracts. The sampling of atmospheric PM with diameter

Author:
Publisher: World Health Organization
ISBN:
Category : House & Home
Languages : en
Pages : 488

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This book presents WHO guidelines for the protection of public health from risks due to a number of chemicals commonly present in indoor air. The substances considered in this review, i.e. benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons (especially benzo[a]pyrene), radon, trichloroethylene and tetrachloroethylene, have indoor sources, are known in respect of their hazardousness to health and are often found indoors in concentrations of health concern. The guidelines are targeted at public health professionals involved in preventing health risks of environmental exposures, as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. They provide a scientific basis for legally enforceable standards.

Author: Jing Chen
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Erich Clar
Publisher: John Wiley & Sons
ISBN:
Category : Science
Languages : en
Pages : 144

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 22

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Book Description

Author: Sponsored by The Health Effects Institute
Publisher: National Academies Press
ISBN: 0309037263
Category : Science
Languages : en
Pages : 703

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"The combination of scientific and institutional integrity represented by this book is unusual. It should be a model for future endeavors to help quantify environmental risk as a basis for good decisionmaking." â€"William D. Ruckelshaus, from the foreword. This volume, prepared under the auspices of the Health Effects Institute, an independent research organization created and funded jointly by the Environmental Protection Agency and the automobile industry, brings together experts on atmospheric exposure and on the biological effects of toxic substances to examine what is knownâ€"and not knownâ€"about the human health risks of automotive emissions.