Chamber Investigations of Secondary Organic Aerosol Formation
Author: David Rea Cocker
Publisher:
Published: 2001
Total Pages: 694
ISBN-13:
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Author: David Rea Cocker
Publisher:
Published: 2001
Total Pages: 694
ISBN-13:
DOWNLOAD EBOOKAuthor: Christine Lauren Loza
Publisher:
Published: 2014
Total Pages: 336
ISBN-13:
DOWNLOAD EBOOKAuthor: Arthur W. H. Chan
Publisher:
Published: 2010
Total Pages: 726
ISBN-13:
DOWNLOAD EBOOKAuthor: Xuan Zhang
Publisher:
Published: 2015
Total Pages: 562
ISBN-13:
DOWNLOAD EBOOKOur understanding of the processes and mechanisms by which secondary organic aerosol (SOA) is formed is derived from laboratory chamber studies. In the atmosphere, SOA formation is primarily driven by progressive photooxidation of SOA precursors, coupled with their gas-particle partitioning. In the chamber environment, SOA-forming vapors undergo multiple chemical and physical processes that involve production and removal via gas-phase reactions; partitioning onto suspended particles vs. particles deposited on the chamber wall; and direct deposition on the chamber wall. The main focus of this dissertation is to characterize the interactions of organic vapors with suspended particles and the chamber wall and explore how these intertwined processes in laboratory chambers govern SOA formation and evolution. A Functional Group Oxidation Model (FGOM) that represents SOA formation and evolution in terms of the competition between functionalization and fragmentation, the extent of oxygen atom addition, and the change of volatility, is developed. The FGOM contains a set of parameters that are to be determined by fitting of the model to laboratory chamber data. The sensitivity of the model prediction to variation of the adjustable parameters allows one to assess the relative importance of various pathways involved in SOA formation. A critical aspect of the environmental chamber is the presence of the wall, which can induce deposition of SOA-forming vapors and promote heterogeneous reactions. An experimental protocol and model framework are first developed to constrain the vapor-wall interactions. By optimal fitting the model predictions to the observed wall-induced decay profiles of 25 oxidized organic compounds, the dominant parameter governing the extent of wall deposition of a compound is identified, i.e., wall accommodation coefficient. By correlating this parameter with the molecular properties of a compound via its volatility, the wall-induced deposition rate of an organic compound can be predicted based on its carbon and oxygen numbers in the molecule. Heterogeneous transformation of delta-hydroxycarbonyl, a major first-generation product from long-chain alkane photochemistry, is observed on the surface of particles and walls. The uniqueness of this reaction scheme is the production of substituted dihydrofuran, which is highly reactive towards ozone, OH, and NO3, thereby opening a reaction pathway that is not usually accessible to alkanes. A spectrum of highly-oxygenated products with carboxylic acid, ester, and ether functional groups is produced from the substituted dihydrofuran chemistry, thereby affecting the average oxidation state of the alkane-derived SOA. The vapor wall loss correction is applied to several chamber-derived SOA systems generated from both anthropogenic and biogenic sources. Experimental and modeling approaches are employed to constrain the partitioning behavior of SOA-forming vapors onto suspended particles vs. chamber walls. It is demonstrated that deposition of SOA-forming vapors to the chamber wall during photooxidation experiments can lead to substantial and systematic underestimation of SOA. Therefore, it is likely that a lack of proper accounting for vapor wall losses that suppress chamber-derived SOA yields contribute substantially to the underprediction of ambient SOA concentrations in atmospheric models.
Author: Aristeidis Voliotis
Publisher:
Published: 2021
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Nga Lee Ng
Publisher:
Published: 2007
Total Pages: 972
ISBN-13:
DOWNLOAD EBOOKAuthor: Axel Metzger
Publisher:
Published: 2008
Total Pages: 140
ISBN-13:
DOWNLOAD EBOOKAuthor: Yingdi Liu
Publisher:
Published: 2011
Total Pages: 76
ISBN-13: 9781124940335
DOWNLOAD EBOOKThis thesis is only a part of my research work. For more information about my other work, including cavity ring down spectroscopy studies for peroxy radical, aerosol optical extinction, transparent thin and time of flight mass spectrometry studies for the initial steps of ozone and alkenes reaactions, please refer to my PhD thesis in Chemistry department, UC-Riverside.
Author: Shunsuke Nakao
Publisher:
Published: 2012
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAuthor: Ian Barnes
Publisher: Springer Science & Business Media
Published: 2006-01-13
Total Pages: 492
ISBN-13: 9781402042317
DOWNLOAD EBOOKThe 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.