Download or read book Aging of Biomass Burning Aerosols and Formation of Secondary Organic Aerosols Over West Africa written by Gerard Capes and published by . This book was released on 2009 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ageing of Biomass Burning Aerosols and Formation of Secondary Organic Aerosols Over West Africa written by Gerard Capes and published by . This book was released on 2009 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Towards a Comprehensive Analysis of the Impact Biomass Burning Aerosols Have on the West African Monsoon written by Osinachi Ajoku and published by . This book was released on 2020 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation is motivated by the lack of research depth on the influence biomass burning produced aerosols impose on West African monsoon dynamics during daily time scales. The impacts of such aerosols on atmospheric thermodynamics and cloud microphysics are investigated using a combination of satellite observations and global climate model simulations. Using observations, we find (1) suppression of precipitation rates over the Guinea coastline with elevated aerosol transport and (2) an increase in rates with decreased aerosol amounts. Decreases in the amount of shortwave radiation reaching the surface over land and ocean attributed to increases in low-level cloud coverage and the absorptive nature of biomass aerosols observed in nature on dirty conditions are matched with reductions in convective available potential energy (CAPE), vertical air mixing essential for deep-convection cloud cover. Increased aerosol content is also associated with decreases in cloud droplet effective radius, a defining feature of aerosol indirect effects. Guided by available observations, model experiments are designed for NCAR's CESM2 with meteorology being nudged to observations using MERRA2 reanalysis to visualize data not available through such observations. Simulations successfully reproduce aerosol transport and corresponding precipitation changes found in observations. However, this model is not in agreement with changes in low-level cloud fraction which leads to increases (decreases) in shortwave radiation reaching the surface (top of atmosphere) during dirty conditions. Our model simulations show that aerosol semidirect and indirect effects interact together to alter cloud formation processes and ultimately control the precipitation response. Throughout the equatorial Atlantic, smoke aerosols impact the structure of stratocumulus to cumulus transition (SCT) through an alteration of atmospheric stability and moisture availability. Boundary layer deepening and increasing sea surface temperatures put the location of this transition within the Gulf of Guinea. Increased low-level clouds occur over the Atlantic cold tongue where aerosol layers reside above low cloud tops, reflecting a negative aerosol semidirect effect. Coupled with significant changes in cloud top height and tropospheric stability further South, these aerosol effects combine to extend in space during increased aerosol loading episodes.
Download or read book Biomass Burning Aerosols from African Wildfires written by Huihui Wu and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Observations of Secondary Organic Aerosol Production and Soot Aging Under Atmospheric Conditions Using a Novel Environmental Aerosol Chamber written by Crystal Glen and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Secondary organic aerosols (SOA) comprise a substantial fraction of the total global aerosol budget. While laboratory studies involving smog chambers have advanced our understanding of the formation mechanisms responsible for SOA, our knowledge of the processes leading to SOA production under ambient gaseous and particulate concentrations as well as the impact these aerosol types have on climate is poorly understood. Although the majority of atmospheric aerosols scatter radiation either directly or indirectly by serving as cloud condensation nuclei, soot is thought to have a significant warming effect through absorption. Like inorganic salts, soot may undergo atmospheric transformation through the vapor condensation of non-volatile gaseous species which will alter both its chemical and physical properties. Typical smog chamber studies investigating the formation and growth of SOA as well as the soot aging process are temporally limited by the initial gaseous concentrations injected into the chamber environment. Furthermore, data interpretation from such experiments is generally restricted to the singular gaseous species under investigation. This dissertation discusses the use of a new aerosol chamber designed to study the formation and growth of SOA and soot aging under atmospherically relevant conditions. The Ambient Aerosol Chamber for Evolution Studies (AACES) was deployed at three field sites where size and hygroscopic growth factor (HGF) of ammonium sulfate seed particles was monitored over time to examine the formation and growth of SOA. Similar studies investigating the soot aging process were also conducted in Houston, TX. It is shown that during the ambient growth of ammonium sulfate seed particles, as particle size increases, hygroscopic growth factors decrease considerably resulting in a significant organic mass fraction in the particle phase concluding an experiment. Observations of soot aging show an increase in measured size, HGF, mass and single scattering albedo. Ambient growth rate comparisons with chamber growth yielded similar trends verifying the use of AACES to study aerosol aging. Based on the results from this study, it is recommended that AACES be employed in future studies involving the production and growth of SOA and soot aging under ambient conditions in order to bridge the gaps in our current scientific knowledge.
Download or read book Formation Ageing and Thermal Properties of Secondary Organic Aerosol Elektronisk Resurs written by and published by . This book was released on 2013 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carbonaceous Aerosol Study Using Advanced Particle Instrumentation written by Li Qi and published by . This book was released on 2010 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the evolution of carbonaceous aerosol in the atmosphere was conducted with special focus on primary biomass burning and secondary organic aerosol (SOA) processing. The work is broken down into two major components: the organic aerosol mass released from biomass burning and the evolution of SOA with special emphasis on formation routes. The biomass burning work explored the evolution of organic aerosol emissions as a function of modified combustion efficiency with correlations drawn between levoglucosan emissions and wood-type, combustion type (flaming, mixed, smoldering) using high resolution aerosol mass spectrometry. The SOA work includes insights into the mechanism for SOA formation from aromatics including the impacts of temperature and particle-aging. This work conclusively demonstrates that gas-particle partitioning theory combined with enthalpies of formation are insufficient to model the formation of SOA as a function of time; that the presence of secondary reactions, in both the particle and gas-phase continue to evolve the aerosol beyond that typically simulated in environmental chambers; and that current mechanisms for SOA formation from aromatics fail to explain isotopically labeled experiments while conclusively ruling out the importance of organic nitrate products.
Download or read book The Formation and Aging of Secondary Organic Aerosol from Alpha pinene Oxidation written by Kaytlin Henry and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantification of Absorption Due to Black and Brown Carbon from Biomass Burning and Parameterizations for Comparison to Climate Models Result written by Rudra Prasad Pokhrel and published by . This book was released on 2017 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation examines the optical properties of fresh and aged biomass burning aerosols, parameterization of these properties, and development of new instrumentation and calibration techniques to measure aerosol optical properties. Data sets were collected from the fourth Fire Lab at Missoula Experiment (FLAME-4) that took place from October 15 to November 16, 2012. Biomass collected from the various parts of the world were burned under controlled laboratory conditions and fresh emissions from different stages of burning were measured and analyzed. Optical properties of aged aerosol under different conditions was also explored. A photoacoustic absorption spectrometer (PAS) was built and integrated with a newly designed thermal denuder to improve upon observations made during Flame-4. A novel calibration technique for the PAS was developed. Single scattering albedo (SSA) and absorption Angstrom exponent (AAE) from 12 different fuels with 41 individual burns were estimated and parameterized with modified combustion efficiency (MCE) and the ratio of elemental carbon (EC) to organic carbon (OC) mass. The EC / OC ratio has better capability to parameterize SSA and AAE than MCE. The simple linear regression model proposed in this study accurately predicts SSA during the first few hours of plume aging with the ambient data from a biomass burning event. In addition, absorption due to brown carbon (BrC) can significantly lower the SSA at 405 nm resulting in a wavelength dependence of SSA. Furthermore, smoldering dominated burns have larger AAE values while flaming dominated burns have smaller AAE values indicating a large fraction of BrC is emitted during the smoldering stage of the burn. Enhancement in BC absorption (E[superscript]A[superscript]b[superscript]s) due to coating by absorbing and non-absorbing substances is estimated at 405 nm and 660 nm. Relatively smaller values of E[superscript]A[superscript]b[superscript]s at 660 nm compared to 405 nm suggests lensing is a less important contributor to biomass burning aerosol absorption at lower wavelengths. Multiple burns of the same fuel produced significantly different E[superscript]A[superscript]b[superscript]s values at 405 nm, but show good correlation with the EC/OC ratio indicating less dependency on fuel type and more dependency on burn conditions. In addition, absorption due to BrC can contribute up to 92 % of the total biomass burning aerosol absorption at 405 nm and up to 58 % of the total absorption at 532 nm. Indicating BrC absorption in biomass burning emissions is equally or more important than the absorption due to BC at short wavelengths. Furthermore, fractional absorption due to BrC shows reasonably good correlation with EC/OC ratio and AAE.Primary organic aerosol is found to be more volatile than secondary organic aerosol and it is found that the thermal denuder deployed in this study removes less organic aerosol if secondary organic aerosol is present. SSA at 532 nm remains constant during different conditions of aging while SSA at 405 nm increases under certain conditions suggesting the degradation of BrC. Decreases in AAE under the same experiment further support the proposed BrC degradation. The novel thermal denuder designed completely removes non-refractory material and can be used under higher flow rates (maximum of 5 LPM) than the most commercially available thermal denuders. The new calibration techniques proposed for the photoacousitc absorption spectrometer will reduce uncertainty during calibration compared to the conventional calibration methods.
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 Photolytic Aging of 4 nitrophenol written by Lydia Dolvin and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic aerosols in the atmosphere have a large impact on global climate and human health. Understanding the lifetimes and fates of these organics in the atmosphere is imperative for optimizing climate models and characterizing their contributions to net atmospheric warming. The warming and cooling properties of aerosols are related to their abilities to absorb or scatter light. Brown carbon is a type of organic aerosol that is of particular interest due to its ability to absorb light in the visible range. These absorption and scattering properties can change, however, if the aerosols are subjected to photolytic or chemical aging. These aging processes are limiting factors on an aerosol’s atmospheric lifetime. In the atmosphere aerosols exist in the dry and aqueous phase. Aqueous aerosols may be found in cloud-water systems, where photolytic and chemical aging can still take place. The literature reports characterizations of different secondary organic aerosol (SOA) component lifetimes in these cloud-water systems, but often does not investigate these lifetimes in “dirty” systems where more than one type of SOA molecule exists. This overlooks the potential for interactions between aerosols of different compositions and ages. In this work, we investigate the photolytic lifetimes of 4-nitrophenol under atmospheric cloud-water conditions. We characterize these lifetimes both alone and in a mixed system with a-pinene SOA by analyzing the kinetics of 4-nitrophenol photolysis. The presence of SOA seems to have an important impact on the photolytic lifetimes of 4-nitrophenol, with fresh SOA accelerating the rate of photo-decay and aged SOA slowing it. We hypothesize that OH radicals produced as photo-products contribute to the photo-decay of this brown carbon when in a system with other organic SOA.
Download or read book Manual on Codes written by World Meteorological Organization and published by . This book was released on 2001 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Multiphase Chemistry written by Hajime Akimoto and published by John Wiley & Sons. This book was released on 2020-03-27 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important guide that highlights the multiphase chemical processes for students and professionals who want to learn more about aerosol chemistry Atmospheric Multiphase Reaction Chemistry provides the information and knowledge of multiphase chemical processes and offers a review of the fundamentals on gas-liquid equilibrium, gas phase reactions, bulk aqueous phase reactions, and gas-particle interface reactions related to formation of secondary aerosols. The authors—noted experts on the topic—also describe new particle formation, and cloud condensation nuclei activity. In addition, the text includes descriptions of field observations on secondary aerosols and PM2.5. Atmospheric aerosols play a critical role in air quality and climate change. There is growing evidence that the multiphase reactions involving heterogeneous reactions on the air-particle interface and the reactions in the bulk liquid phase of wet aerosol and cloud/fog droplets are important processes forming secondary aerosols in addition to gas-phase oxidation reactions to form low-volatile compounds. Comprehensive in scope, the book offers an understanding of the topic by providing a historical overview of secondary aerosols, the fundamentals of multiphase reactions, gas-phase reactions of volatile organic compounds, aqueous phase and air-particle interface reactions of organic compound. This important text: Provides knowledge on multiphase chemical processes for graduate students and research scientists Includes fundamentals on gas-liquid equilibrium, gas phase reactions, bulk aqueous phase reactions, and gas-particle interface reactions related to formation of secondary aerosols Covers in detail reaction chemistry of secondary organic aerosols Written for students and research scientists in atmospheric chemistry and aerosol science of environmental engineering, Atmospheric Multiphase Reaction Chemistry offers an essential guide to the fundamentals of multiphase chemical processes.
Download or read book Atmospheric Aerosols written by Olivier Boucher and published by Springer. This book was released on 2015-05-18 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook aims to be a one stop shop for those interested in aerosols and their impact on the climate system. It starts with some fundamentals on atmospheric aerosols, atmospheric radiation and cloud physics, then goes into techniques used for in-situ and remote sensing measurements of aerosols, data assimilation, and discusses aerosol-radiation interactions, aerosol-cloud interactions and the multiple impacts of aerosols on the climate system. The book aims to engage those interested in aerosols and their impacts on the climate system: graduate and PhD students, but also post-doctorate fellows who are new to the field or would like to broaden their knowledge. The book includes exercises at the end of most chapters. Atmospheric aerosols are small (microscopic) particles in suspension in the atmosphere, which play multiple roles in the climate system. They interact with the energy budget through scattering and absorption of solar and terrestrial radiation. They also serve as cloud condensation and ice nuclei with impacts on the formation, evolution and properties of clouds. Finally aerosols also interact with some biogeochemical cycles. Anthropogenic emissions of aerosols are responsible for a cooling effect that has masked part of the warming due to the increased greenhouse effect since pre-industrial time. Natural aerosols also respond to climate changes as shown by observations of past climates and modelling of the future climate.
Download or read book Environmental External Costs of Transport written by Rainer Friedrich and published by Springer Science & Business Media. This book was released on 2001-09-25 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport causes a wide range of damage to human health, ecosytems and materials which are not reflected in the prices for transport. Thus, the damage caused by cars, planes, ships and trains should be known and transformed into monetary values, so called external costs. Within this book, a method to estimate the external costs stemming from the emissions of atmospheric pollutants of transport, including damage from greenhouse gases, fine particles, ozone, nitrous oxides, benzene and other carcinogenic substances, is described and applied to calculate the external costs of a huge number of current and future transport techniques operating in different locations all over Europe. A number of case studies demonstrate how the results can be used to aid policy decisions. The book is an important basis for assessing transport techniques, discussing transport taxes and charges and implementing ecopolitical instruments.
Download or read book Secondary Organic Aerosol Formation from Emissions from Combustion Sources written by Marissa A. Miracolo and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Scattering Reviews 8 written by Alexander A. Kokhanovsky and published by Springer Science & Business Media. This book was released on 2013-06-12 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light scattering review (vol 8) is aimed at the presentation of recent advances in radiative transfer and light scattering optics. The topics to be covered include: scattering of light by irregularly shaped particles suspended in atmosphere (dust, ice crystals), light scattering by particles much larger as compared the wavelength of incident radiation, atmospheric radiative forcing, astrophysical radiative transfer, radiative transfer and optical imaging in biological media, radiative transfer of polarized light, numerical aspects of radiative transfer.
