ORCID Profile
0000-0003-4513-4187
Current Organisation
University of North Carolina at Chapel Hill
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Publisher: American Chemical Society (ACS)
Date: 21-01-2019
DOI: 10.26434/CHEMRXIV.7597397.V1
Abstract: Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), a key isoprene oxidation product, with inorganic sulfate aerosol yields substantial amounts of secondary organic aerosol (SOA) through the formation of organosulfur. The extent and implications of inorganic-to-organic sulfate conversion, however, are unknown. Herein, we reveal that extensive consumption of inorganic sulfate occurs, which increases with the IEPOX-to-inorganic sulfate ratio (IEPOX:Sulf inorg ), as determined by laboratory and field measurements. We further demonstrate that organosulfur greatly modifies critical aerosol properties, such as acidity, morphology, viscosity, and phase state. These new mechanistic insights reveal that changes in SO 2 emissions, especially in isoprene-dominated environments, will significantly alter biogenic SOA physicochemical properties. Consequently, IEPOX:Sulf inorg will play a central role in understanding historical climate and determining future impacts of biogenic SOA on global climate and air quality.
Publisher: American Geophysical Union (AGU)
Date: 11-2005
DOI: 10.1029/2005GL023799
Publisher: American Chemical Society (ACS)
Date: 09-2016
Abstract: Atmospheric oxidation of isoprene under low-NOx conditions leads to the formation of isoprene hydroxyhydroperoxides (ISOPOOH). Subsequent oxidation of ISOPOOH largely produces isoprene epoxydiols (IEPOX), which are known secondary organic aerosol (SOA) precursors. Although SOA from IEPOX has been previously examined, systematic studies of SOA characterization through a non-IEPOX route from 1,2-ISOPOOH oxidation are lacking. In the present work, SOA formation from the oxidation of authentic 1,2-ISOPOOH under low-NOx conditions was systematically examined with varying aerosol compositions and relative humidity. High yields of highly oxidized compounds, including multifunctional organosulfates (OSs) and hydroperoxides, were chemically characterized in both laboratory-generated SOA and fine aerosol s les collected from the southeastern U.S. IEPOX-derived SOA constituents were observed in all experiments, but their concentrations were only enhanced in the presence of acidified sulfate aerosol, consistent with prior work. High-resolution aerosol mass spectrometry (HR-AMS) reveals that 1,2-ISOPOOH-derived SOA formed through non-IEPOX routes exhibits a notable mass spectrum with a characteristic fragment ion at m/z 91. This laboratory-generated mass spectrum is strongly correlated with a factor recently resolved by positive matrix factorization (PMF) of aerosol mass spectrometer data collected in areas dominated by isoprene emissions, suggesting that the non-IEPOX pathway could contribute to ambient SOA measured in the Southeastern United States.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8EM00308D
Abstract: A developed non-thermal analytical method effectively resolves and quantifies major IEPOX-SOA components in PM 2.5 .
Publisher: Elsevier BV
Date: 03-2017
Publisher: American Chemical Society (ACS)
Date: 23-01-2003
DOI: 10.1021/ES020622F
Abstract: A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter s les collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter s les collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected s les from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient s les, four source s les, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke s le were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient s les and a coal fly ash s le showed moderate sensitivity to temperature program, while a carbon black s le and a s le of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.
Publisher: American Chemical Society (ACS)
Date: 07-06-2019
Location: United States of America
No related grants have been discovered for Barbara Turpin.