title: Simulating Aqueous-Phase Isoprene-Epoxydiol (IEPOX) Secondary Organic Aerosol Production During the 2013 Southern Oxidant and Aerosol Study (SOAS).
abstract: The lack of statistically robust relationships between IEPOX (isoprene epoxydiol)-derived SOA (IEPOX SOA) and aerosol liquid water and pH observed during the 2013 Southern Oxidant and Aerosol Study (SOAS) emphasizes the importance of modeling the whole system to understand the controlling factors governing IEPOX SOA formation. We present a mechanistic modeling investigation predicting IEPOX SOA based on Community Multiscale Air Quality (CMAQ) model algorithms and a recently introduced photochemical box model, simpleGAMMA. We aim to (1) simulate IEPOX SOA tracers from the SOAS Look Rock ground site, (2) compare the two model formulations, (3) determine the limiting factors in IEPOX SOA formation, and (4) test the impact of a hypothetical sulfate reduction scenario on IEPOX SOA. The estimated IEPOX SOA mass variability is in similar agreement (r2∼ 0.6) with measurements. Correlations of the estimated and measured IEPOX SOA tracers with observed aerosol surface area (r2∼ 0.5-0.7), rate of particle-phase reaction (r2∼ 0.4-0.7), and sulfate (r2∼ 0.4-0.5) suggest an important role of sulfate in tracer formation via both physical and chemical mechanisms. A hypothetical 25% reduction of sulfate results in ∼70% reduction of IEPOX SOA formation, reaffirming the importance of aqueous phase chemistry in IEPOX SOA production.
authors.affiliation: National Exposure Research Laboratory, U,S, EPA , Research Triangle Park, North Carolina 27711, United States.|Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina , Chapel Hill, North Carolina 27599, United States.|Earth Observatory of Singapore, Nanyang Technological University , Singapore 639798, Singapore.
authors.forename: Sri Hapsari
authors.identifier: http://orcid.org/0000-0002-5715-9157
authors.initials: SH
authors.lastname: Budisulistiorini
authors.affiliation: School of Earth and Atmospheric Sciences, Georgia Institute of Technology , Atlanta, Georgia 30322, United States.|School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta , Georgia 30322, United States.|Institute of Chemical Engineering Sciences, Foundation for Research and Technology - Hellas , Patras GR-26504, Greece.|Institute of Environmental Research and Sustainable Development, National Observatory of Athens , Palea Penteli GR-15236, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Nenes
authors.affiliation: Department of Chemistry, University of California , Irvine, California 92617, United States.
authors.forename: Annmarie G
authors.identifier: http://orcid.org/0000-0002-8574-1507
authors.initials: AG
authors.lastname: Carlton
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina , Chapel Hill, North Carolina 27599, United States.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Surratt
authors.affiliation: Department of Chemical Engineering, Columbia University , New York, New York 10027, United States.
authors.forename: V Faye
authors.identifier: http://orcid.org/0000-0003-0379-6916
authors.initials: VF
authors.lastname: McNeill
authors.affiliation: National Exposure Research Laboratory, U,S, EPA , Research Triangle Park, North Carolina 27711, United States.
authors.forename: Havala O T
authors.identifier: http://orcid.org/0000-0002-2014-2140
authors.initials: HOT
authors.lastname: Pye
mesh_terms: D000336:Aerosols; D000393:Air Pollutants; D001272:Atmosphere; D016877:Oxidants; D013431:Sulfates; D014867:Water
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D016877:Oxidants; D013431:Sulfates; D014867:Water