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.

Pyrolysis of Organic Molecules with Applications to Health and Environmental Issues, the 28th volume in the Techniques and Instrumentation in Analytical Chemistry series, gives a systematic and comprehensive description of pyrolysis of non-polymeric organic molecules. Pyrolysis is involved in many practical applications as well as in many common human activities, but harmful compounds can be generated in the process. The study of pyrolysis and of the formation of undesirable compounds as a result of pyrolytic processes is of considerable interest to chemists, chemical engineers, and toxicologists. - Pyrolysis results for compounds not previously studied or reported - Updated information from a large body of results published on pyrolysis of individual compounds or classes of compounds - Information on mechanisms and kinetics of numerous pyrolytic processes

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.

"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.

This book presents the most up-to-date research and information regarding the origin, chemistry, fate and health impacts of airborne particulate matter in urban areas, a topic which has received a great deal of attention in recent years due to documented relationships between exposure and health effects such as asthma. With internationally recognised researchers and academics presenting their work and key concepts and approaches from a variety of disciplines, including environmental and analytical chemistry, biology, toxicology, mineralogy and the geosciences, this book addresses the topic of urban airborne particulate matter in a comprehensive, multidisciplinary manner. Topics and research addressed in the book range from common methodological approaches used to sample and analyse the composition of airborne particulates to our knowledge regarding their potential to impact human health and the various policy approaches taken internationally to regulate particulate matter levels.

This book discusses different aspects of energy consumption and environmental pollution, describing in detail the various pollutants resulting from the utilization of natural resources and their control techniques. It discusses diagnostic techniques in a simple and easy-to-understand manner. It will be useful for engineers, agriculturists, environmentalists, ecologists and policy makers involved in area of pollutants from energy, environmental safety, and health sectors.

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.

Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:

Complete coverage of air pollution from its sources to its health and environmental impacts, for advanced students and researchers.

Process-Induced Food Toxicants combines the analytical, health, and risk management issues relating to all of the currently known processing-induced toxins that may be present in common foods. It considers the different processing methods used in the manufacture of foods, including thermal treatment, drying, fermentation, preservation, fat processing, and high hydrostatic pressure processing, and the potential contaminants for each method. The book discusses the analysis, formation, mitigation, health risks, and risk management of each hazardous compound. Also discussed are new technologies and the impact of processing on nutrients and allergens.