Download or read book Influence of Environmental Parameters on Secondary Organic Aerosol Formation written by Bethany A. Warren and published by . This book was released on 2008 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atmospheric Aerosols written by Rekha Kale and published by Scitus Academics LLC. This book was released on 2015-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric Aerosols is a vital problem in current environmental research due to its importance in atmospheric optics, energetics, radiative transfer studies, chemistry, climate, biology and public health. Aerosols can influence the energy balance of the terrestrial atmosphere, the hydrological cycle, atmospheric dynamics and monsoon circulations. Because of the heterogeneous aerosol field with large spatial and temporal variability and reduction in uncertainties in aerosol quantification is a challenging task in atmospheric sciences. Keeping this in view the present study aims to assess the impact of aerosols on coastal Indian station Visakhapatnam and the adjoining Bay of Bengal. An aerosol is a colloid of fine solid particles or liquid droplets, in air or another gas. Aerosols can be natural or not. Examples of natural aerosols are fog, forest exudates and geyser steam.

Download or read book Environmental Chemistry of Aerosols written by Ian Colbeck and published by John Wiley & Sons. This book was released on 2008-03-24 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles are ubiquitous in the Earth’s atmosphere and are central to many environmental issues such as climate change, stratospheric ozone depletion and air quality. In urban environments, aerosol particles can affect human health through their inhalation. Atmospheric aerosols originate from naturally occurring processes, such as volcanic emissions, sea spray and mineral dust emissions, or from anthropogenic activity such as industry and combustion processes. Aerosols present pathways for reactions, transport, and deposition that would not occur in the gas phase alone. Understanding the ways in which aerosols behave, evolve, and exert these effects requires knowledge of their formation and removal mechanism, transport processes, as well as their physical and chemical characteristics. Motivated by climate change and adverse health effects of traffic-related air pollution, aerosol research has intensified over the past couple of decades, and recent scientific advances offer an improved understanding of the mechanisms and factors controlling the chemistry of atmospheric aerosols. Environmental Chemistry of Aerosols brings together the current state of knowledge of aerosol chemistry, with chapters written by international leaders in the field. It will serve as an authoritative and practical reference for scientists studying the Earth’s atmosphere and as an educational and training resource for both postgraduate students and professional atmospheric scientists.

Download or read book Prim rliteratur 1817 1953 written by and published by . This book was released on 1960 with total page 191 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 Secondary Organic Aerosol Formation from Aromatic Hydrocarbons written by Chen Song and published by . This book was released on 2006 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Secondary Organic Aerosol Formation Indoors written by Chunyi Wang and published by . This book was released on 2019 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: People in developed countries spend about 90% of their time indoors, so controlling in-door air quality (IAQ) is of primary importance for not harming public health. Airborne particu-late matter (PM) is one of the most problematic pollutants indoors, since exposure to particles with aerodynamic diameters smaller than 2.5 Îơm (i.e, PM2.5) is associated with respiratory dis-eases, as well as morbidity and mortality outcomes. Organic aerosol components, so called organic aerosol (OA), generally comprise the ma-jor portion of indoor PM, owing to its large indoor emission. One important component of OA indoors is secondary organic aerosol (SOA), which are condensed phase particles composed of semi- and low-volatility compounds. Most research has focused on SOA generated by terpene ozonolysis occurring in the gas phase. This work, however, explores a lesser researched for-mation mechanism, which is the possibility of airborne SOA generated by ozone surface reac-tions with sorbed squalene (C30H50), which is a nonvolatile constituent of skin oil. As such, thirteen steady state chamber experiments were performed to measure the SOA formation en-tirely initiated by ozone reactions with squalene sorbed to glass at two RH conditions of 21% and 51%, in the absence of seed particles. SOA was initiated from these surface reactions, and all experiments but one exhibited nucleation and mass formation. Mass formation increased with ozone concentration at RH = 51% while nucleation was more obvious at RH = 21%. Additionally, most indoor OA, either emitted or generated (i.e., not only SOA), is at composed of semivolatile compounds (SVOCs) in a state of dynamic equilibrium between gas and particle phases. Filters might have a reduced efficiency on removing these kinds of particles since they coexist in gas and condensed aerosol phases. The preferential filtration of particle phase material of the OA system could disrupt the equilibrium, and the removed aerosols might be enhanced by desorption from surfaces and repartitioning from gas phase. To explore this phenomenon, three types of particles, including non-volatile ammonium sulfate ((NH4)2SO4) aerosol, incense aerosol (which might be partly semi-volatile), and SOA derived from ozone + d-limonene reactions (the majority of which are SVOCs), were characterized and compared in terms of their effective removal by a portable air cleaner. For this comparison, the metric of the Clean Air Delivery Rate, CADR (m3/h), was used, which is the volumetric flow of pollutant-free air produced by an air cleaner. Results demonstrated that the lowest effective CADR was for SOA, followed by the incense, and then the ammonium sulfate particles, indicating a repar-titioning processes reduced the filter efficiency. Then a model based on the principles of desorp-tion and repartition process was developed, to quantify the reduced CADR as a function of par-ticle concentration and distribution, in terms of parameter ATSP, which is the ratio of particle surface area to mass. Finally, the influence of the above two parameters on amount of CADR reduction was discussed. Using some details gleaned from the above two experimental studies, a thermodynamic equilibrium model was developed using the volatile basis set (VBS), to predict indoor organic aerosol concentrations and behavior. The model outcomes are the total organic mass indoors (gas + condensed phase), and the fraction of it that partitions to the aerosol phase, including that existing as SOA formed by ozone + d-limonene reactions. With this model, the total OA concentration was simulated at key locations in an indoor environment, such as in the occupied space and different positions in a building mechanical system. The impacts of different condi-tions were compared, including commercial against residential buildings, surface against gas reactions, and winter against summer, within a Monte Carlo framework. Indoor OA concentra-tion indoors were higher when reactions were involved, and gas phase reactions had much more influence on SOA than surface reactions. Finally, the result dataset was used to evaluate the influence of key factors on the indoor OA concentrations, using multiple linear regression sen-sitivity methods. The most important factor that enhanced indoor particles was d-limonene emission rate with average SRC of 0.73, while the negative related factors were filtration effi-ciency with SRC of -0.33 for commercial and surface deposition rate with SRC of -0.22 for resi-dential buildings. Beyond the three SOA studies discussed above, humidifiers used indoors might be strong PM emitters. So, as a supplementary piece, this work also investigated the influence of three humidifier types (ultrasonic, evaporative, and steam humidifiers), and water type used (tap water, de-ionized (DI) water or distilled water), on indoor aerosol number/mass concentra-tions by performing 16 experiments. Particle size distribution during emission periods and size-resolved emission rates were explored to compare the emission ability of humidifiers. Two lung deposition models were also applied to simulate the deposition percentage of particles breathed in on three lung regions (HA, TB, and AL), and total percentage on varying age groups. Results showed that two year-old group was most vulnerable, with number deposition fractions of 0.36, compared with 0.25 for adults. Furthermore, roughly 70% of the total emitted particles pene-trates into the AL region of the lung.

Download or read book Insights Into Predicting Secondary Organic Aerosol Formation from Anthropogenic Volatile Organic Compounds written by Lijie Li and published by . This book was released on 2016 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding secondary organic aerosol (SOA) formation is of critical importance to public health and global climate. SOA formation from anthropogenic volatile organic compounds (VOCs) is influenced by NO, precursor molecular structure, oxidation conditions and other factors. This dissertation explores the impact of NO effect and molecular structure for two categories of VOCs at urban atmosphere relevant conditions by utilizing the state of art 90 m3 UCR/CE-CERT chamber facilities.

Download or read book Environmental Simulation Chambers Application to Atmospheric Chemical Processes written by Ian Barnes and published by Springer Science & Business Media. This book was released on 2006-01-13 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives in the first instance descriptions of different types of so-called environment chambers or photoreactors used mainly for the simulation and/or investigation of important chemical processes occurring in the atmosphere. The types of reactor described include outdoor and indoor chambers, temperature regulated chambers and glass and Teflon foil chambers The practical use of chambers is demonstrated in contributions by leading scientists in the field of atmospheric chemistry using, in many cases, current results. The types of atmospherically relevant investigations described include the measurement of reactivities, the measurement of radicals, the measurement of photolysis frequencies and products, kinetic and product studies on the oxidation of different types of hydrocarbons by important oxidant species (OH, N03, 03), formation of secondary organic aerosol from hydrocarbon oxidation etc. A special section includes contributions from eastern European countries which highlight some of the environmental research being performed in these countries. An abridged version of a specially commissioned review by the JRC Ispra on the status of environmental research in eastern European countries is also included in this section.

Download or read book Chemical and Physical Characterization of Secondary Organic Aerosol Formation from Select Agricultural Emissions written by Quentin Gerald James Malloy and published by . This book was released on 2009 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Formation of Secondary Aerosols Under Photolysis written by Chris Canfield and published by . This book was released on 2002 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various studies have researched secondary aerosols to determine the source contributions and environmental parameters contributing to the aerosol and Particulate Matter (PM) 10 loading in the ambient air. The majority of studies abroad consider organic contributions to aerosol loading. Concentrations of ammonia, nitrogen dioxide, and sulfur dioxide present in the air have been confirmed to have an effect on the formation of secondary aerosols in the atmosphere. This thesis studies the effects of nitrogen dioxide, sulfur dioxide, ammonia, and humidity in the air on the formation of secondary aerosols in a photo reactor operating at 340 nm.

Download or read book Physiochemical Properties and Environmental Effects of Secondary Organic Aerosol written by Celia Noemi Cruz and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Properties of Secondary Organic Aerosol in the Ambient Atmosphere written by Christopher James Hennigan and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis characterizes properties of ambient secondary organic aerosol (SOA), an important and abundant component of particulate matter. The findings presented in this thesis are significant because they represent the results from ambient measurements, which are relatively scarce, and because they report on properties of SOA that, until now, were highly uncertain. The analyses utilized the fraction of particulate organic carbon that was soluble in water (WSOCp) to approximate SOA concentrations in two largely different urban environments, Mexico City and Atlanta. In Mexico City, measurements of atmospheric gases and fine particle chemistry were made at a site ~ 30 km down wind of the city center. Using box model analyses and a comparison to ammonium nitrate aerosol, a species whose thermodynamic properties are generally understood, the morning formation and mid-day evaporation of SOA are investigated. In Atlanta, simultaneous measurements of WSOCp and water-soluble organic carbon in the gas phase (WSOCg) were carried out for an entire summer to investigate the sources and partitioning of WSOC. The results suggest that both WSOCp and WSOCg were secondary and biogenic, except possibly in several strong biomass burning events. The gas/particle partitioning of WSOC in Atlanta was investigated through the parameter, Fp, which represented the fraction of WSOC in the particle phase. Factors that appear to influence WSOC partitioning in Atlanta include ambient relative humidity and the WSOCp mass concentration. There was also a relationship between the NOx concentration and Fp, though this was not likely related to the partitioning process. Temperature did not appear to impact Fp, though this may have been due to positive relationships WSOCp and WSOCg each exhibited with temperature. Neither the total Organic Carbon aerosol mass concentration nor the ozone concentration impacted WSOC partitioning.

Download or read book Handbook of Indoor Air Quality written by Yinping Zhang and published by Springer Nature. This book was released on 2022-11-23 with total page 2182 pages. Available in PDF, EPUB and Kindle. Book excerpt: People live in indoor environment about 90% of lifetime and an adult inhales about 15 kg air each day, over 75% of the human body’s daily mass intake (air, food, water). Therefore, indoor air quality (IAQ) is very important to human health. This book provides the basic knowledge of IAQ and highlights the research achievements in the past two decades. It covers the following 12 sections: introduction, indoor air chemicals, indoor air particles, measurement and evaluation, source/sink characteristics, indoor chemistry, human exposure to indoor pollutants, health effects and health risk assessment, IAQ and cognitive performance, standards and guidelines, IAQ control, and air quality in various indoor environments. It provides a combination of an introduction to various aspects on IAQ studies, the current state-of-knowledge, various advances and the perspective of IAQ studies. It will be very helpful for the researchers and technicians in the IAQ and the related fields. It is also useful for experts in other fields and general readers who want to obtain a basic understanding of and research advances in the field of IAQ. A group of experts in IAQ research have been recruited to write the chapters. Their research interests and experience cover the scope of the book. In addition, some experienced experts in IAQ field have been invited as advisors or reviewers to give their comments, suggestions and revisions on the handbook framework and the chapter details. Their contribution guarantees the quality of the book. We are very grateful to them. Last but not least, we express our heartfelt thanks to Prof. Spengler, Harvard University, for writing the foreword of the current Handbook of Indoor Air Quality both as a pioneer scientist who contributed greatly to indoor air science and as an Editor-in-chief of Handbook of Indoor Air Quality 2001, 1st ed. New York: McGraw-Hill. In addition to hard copies, the book is also published online and will be updated by the authors as needed to keep it aligned with current knowledge. These salient features can make the handbook fresh with the research development.

Download or read book The Influence of Formation Temperature on Secondary Organic Aerosol Volatility written by Katherine Smith and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The volatility of secondary organic aerosol (SOA) formed from the dark ozonolysis of [alpha]-pinene in a flow tube at temperatures ranging from 275 to 298 K has been characterized by thermally induced evaporation. The SOA was heated from the formation temperature (T[subscript f]) in a thermodenuder and the temperature-dependent volume loss was measured. The resulting thermograms for the SOA formed at the different temperatures were nearly identical when considered as a function of [delta]T (= T – T[subscript f]), rather than absolute temperature. A kinetic model of aerosol evaporation was used to derive T[subscript f]-specific effective volatility distributions for the SOA. The derived distributions indicate SOA formed at lower temperatures is composed of compounds having higher effective volatilities compared to that formed at higher temperatures. However, the increased abundance of compounds having higher effective volatilities at lower T[subscript f] cannot be explained solely due to increased partitioning into the particle phase due to a decrease in vapor pressures. Instead, much of the dependence on T[subscript f] likely results from T-dependent changes in the fraction of the particles that is monomers versus dimers (or higher order oligomers). The relatively short formation time (

Download or read book Effect of Environmental Conditions on Composition and Photochemistry of Secondary Organic Aerosols written by Mallory Lynn Hinks and published by . This book was released on 2017 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols represent one of the greatest uncertainties in predicting the Earth's future climate. Secondary organic aerosols (SOA) are particularly complicated because they are highly susceptible to change upon exposure to different conditions, such as varying temperatures and relative humidities (RHs), sunlight, and different atmospheric pollutants. The goal of this work was to increase our understanding of the contribution of SOA to the Earth's radiation budget by exploring how different environmental conditions can affect aerosol properties and processes.The first project investigated the effect of viscosity on photochemical kinetics of probe molecules embedded in laboratory-generated SOA. Temperature and RH of the system were varied independently to adjust the viscosity of the SOA and the samples were irradiated. At lower temperatures and humidities both systems exhibited lower photoreaction rates, suggesting that increased viscosity hinders the motion of the molecules in the SOA slowing down their photochemical reactions. This means that molecules trapped inside SOA in cold, dry parts of the atmosphere will photodegrade slower than in warm and humid areas.The next stage of this work was to study the effect of RH on the mass loading and composition of SOA formed from toluene photooxidation. When the RH was increased from 0% to 75%, the yield of toluene SOA made under low NOx conditions decreased by an order of magnitude. High resolution mass spectrometry revealed a significant reduction in the fraction of oligomers present in the SOA made under humid conditions compared to dry conditions. These results suggest that water vapor suppresses oligomer formation in low NOx toluene SOA, reducing aerosol yield. This means that concentrations of toluene SOA in the atmosphere will be dependent on the RH and NOx concentrations.The last stage of this work investigated the interaction between SOA and ammonia. SOA made from toluene, n-hexadecane, or limonene in a chamber was exposed to gaseous ammonia while the mass loading and composition was monitored. These experiments indicated that ammonia could be taken up into SOA, leaving less ammonia in the atmosphere to neutralize atmospheric acids. This leads to a reduction of inorganic aerosols in the atmosphere.

Download or read book Chemistry of the Upper and Lower Atmosphere written by Barbara J. Finlayson-Pitts and published by Elsevier. This book was released on 1999-11-17 with total page 993 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is the most comprehensive and up-to-date treatment of one of the hottest areas of chemical research. The treatment of fundamental kinetics and photochemistry will be highly useful to chemistry students and their instructors at the graduate level, as well as postdoctoral fellows entering this new, exciting, and well-funded field with a Ph.D. in a related discipline (e.g., analytical, organic, or physical chemistry, chemical physics, etc.). Chemistry of the Upper and Lower Atmosphere provides postgraduate researchers and teachers with a uniquely detailed, comprehensive, and authoritative resource. The text bridges the "gap" between the fundamental chemistry of the earth's atmosphere and "real world" examples of its application to the development of sound scientific risk assessments and associated risk management control strategies for both tropospheric and stratospheric pollutants. Serves as a graduate textbook and "must have" reference for all atmospheric scientists Provides more than 5000 references to the literature through the end of 1998 Presents tables of new actinic flux data for the troposphere and stratospher (0-40km) Summarizes kinetic and photochemical date for the troposphere and stratosphere Features problems at the end of most chapters to enhance the book's use in teaching Includes applications of the OZIPR box model with comprehensive chemistry for student use