title: Epoxide as a precursor to secondary organic aerosol formation from isoprene photooxidation in the presence of nitrogen oxides.
abstract: Isoprene is a substantial contributor to the global secondary organic aerosol (SOA) burden, with implications for public health and the climate system. The mechanism by which isoprene-derived SOA is formed and the influence of environmental conditions, however, remain unclear. We present evidence from controlled smog chamber experiments and field measurements that in the presence of high levels of nitrogen oxides (NO(x) = NO + NO2) typical of urban atmospheres, 2-methyloxirane-2-carboxylic acid (methacrylic acid epoxide, MAE) is a precursor to known isoprene-derived SOA tracers, and ultimately to SOA. We propose that MAE arises from decomposition of the OH adduct of methacryloylperoxynitrate (MPAN). This hypothesis is supported by the similarity of SOA constituents derived from MAE to those from photooxidation of isoprene, methacrolein, and MPAN under high-NOx conditions. Strong support is further derived from computational chemistry calculations and Community Multiscale Air Quality model simulations, yielding predictions consistent with field observations. Field measurements taken in Chapel Hill, North Carolina, considered along with the modeling results indicate the atmospheric significance and relevance of MAE chemistry across the United States, especially in urban areas heavily impacted by isoprene emissions. Identification of MAE implies a major role of atmospheric epoxides in forming SOA from isoprene photooxidation. Updating current atmospheric modeling frameworks with MAE chemistry could improve the way that SOA has been attributed to isoprene based on ambient tracer measurements, and lead to SOA parameterizations that better capture the dependency of yield on NO(x).
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
authors.forename: Ying-Hsuan
authors.initials: YH
authors.lastname: Lin
authors.forename: Haofei
authors.initials: H
authors.lastname: Zhang
authors.forename: Havala O T
authors.initials: HO
authors.lastname: Pye
authors.forename: Zhenfa
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Marth
authors.forename: Sarah
authors.initials: S
authors.lastname: Park
authors.forename: Maiko
authors.initials: M
authors.lastname: Arashiro
authors.forename: Tianqu
authors.initials: T
authors.lastname: Cui
authors.forename: Sri Hapsari
authors.initials: SH
authors.lastname: Budisulistiorini
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Sexton
authors.forename: William
authors.initials: W
authors.lastname: Vizuete
authors.forename: Ying
authors.initials: Y
authors.lastname: Xie
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Luecken
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Piletic
authors.forename: Edward O
authors.initials: EO
authors.lastname: Edney
authors.forename: Libero J
authors.initials: LJ
authors.lastname: Bartolotti
authors.forename: Avram
authors.initials: A
authors.lastname: Gold
authors.forename: Jason D
authors.initials: JD
authors.lastname: Surratt
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere / Q000032:analysis*; D002070:Butadienes / Q000737:chemistry* / Q000528:radiation effects; D003198:Computer Simulation; D004852:Epoxy Compounds / Q000737:chemistry*; D045782:Hemiterpenes / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D008689:Methacrylates / Q000737:chemistry; D008956:Models, Chemical; D009589:Nitrogen Oxides / Q000737:chemistry*; D009657:North Carolina; D010084:Oxidation-Reduction; D010420:Pentanes / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D002070:Butadienes; D004852:Epoxy Compounds; D045782:Hemiterpenes; D008689:Methacrylates; D009589:Nitrogen Oxides; D010420:Pentanes; C005059:isoprene; C008384:methacrylic acid
references.citation: Environ Sci Technol. 2006 Mar 15;40(6):1869-77
references.pmid: 16570610
references.citation: J Chem Phys. 2005 Dec 8;123(22):224101
references.pmid: 16375464
references.citation: Atmos Chem Phys Discuss. 2012;12(2):5065-5105
references.pmid: 23457430
references.citation: J Air Waste Manag Assoc. 2003 Dec;53(12):1460-71
references.pmid: 14700133
references.citation: Phys Chem Chem Phys. 2013 Apr 7;15(13):4744-53
references.pmid: 23435763
references.citation: J Chem Phys. 2010 Mar 21;132(11):114303
references.pmid: 20331293
references.citation: Phys Chem Chem Phys. 2009 Dec 14;11(46):11040-53
references.pmid: 19924340
references.citation: Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6640-5
references.pmid: 20080572
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 2;106(22):8835-40
references.pmid: 19451635
references.citation: Environ Sci Technol. 2010 May 1;44(9):3376-80
references.pmid: 20387864
references.citation: J Phys Chem A. 2006 Aug 10;110(31):9665-90
references.pmid: 16884200
references.citation: J Phys Chem A. 2006 Sep 14;110(36):10528-44
references.pmid: 16956234
references.citation: Geosci Model Dev. 2017;10(4):1703-1732
references.pmid: 30147852
references.citation: J Phys Chem A. 2012 Jun 21;116(24):5763-8
references.pmid: 22452294
references.citation: Science. 2009 Aug 7;325(5941):730-3
references.pmid: 19661425
references.citation: Environ Sci Technol. 2010 Nov 15;44(22):8553-60
references.pmid: 20883028
references.citation: Environ Sci Technol. 2012 Jan 3;46(1):250-8
references.pmid: 22103348
references.citation: Science. 1988 Sep 16;241(4872):1473-5
references.pmid: 3420404
references.citation: J Comput Chem. 2003 Jun;24(8):990-6
references.pmid: 12720320
references.citation: Science. 2004 Feb 20;303(5661):1173-6
references.pmid: 14976309
references.citation: J Phys Chem A. 2005 Jul 14;109(27):6031-44
references.pmid: 16833939
references.citation: J Chem Theory Comput. 2009 May 12;5(5):1197-202
references.pmid: 26609710
references.citation: Environ Sci Technol. 2011 May 15;45(10):4438-45
references.pmid: 21520901