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Quantification of particle-bound organic radicals in secondary organic aerosol
journal contribution
posted on 2019-06-18, 00:00 authored by Steven J Campbell, Svetlana StevanovicSvetlana Stevanovic, Branka Miljevic, Steven E Bottle, Zoran Ristovski, Markus KalbererThe chemical composition and evolution of secondary organic aerosol (SOA) in the atmosphere represents one of the largest uncertainties in our current understanding of air quality. Despite vast research, the toxicological mechanisms relating to adverse human health effects upon exposure to particulate matter are still poorly understood. Particle-bound reactive oxygen species (ROS) may substantially contribute to observed health effects by influencing aerosol oxidative potential (OP). The role of radicals in both the formation and aging of aerosol, as well as their contribution to aerosol OP, remains highly uncertain. The profluorescent spin trap BPEAnit (9,10-bis(phenylethynyl)anthracenenitroxide), previously utilized to study combustion-generated aerosol, has been applied to provide the first estimate of particle-bound radical concentrations in SOA. We demonstrate that SOA from different atmospherically important VOC precursors have different particle-bound radical concentrations, estimated for the ozonolysis of α-pinene (0.020 ± 0.0050 nmol/μg), limonene (0.0059 ± 0.0010 nmol/μg), and β-caryophyllene (0.0025 ± 0.00080 nmol/μg), highlighting the potential importance of OH-initiated formation of particle-bound organic radicals. Additionally, the lifetime of particle-bound radical species in α-pinene SOA was estimated, and a pseudo-first-order rate constant of k = 7.3 ± 1.7 × 10-3 s-1 was derived, implying a radical lifetime on the order of minutes.
History
Journal
Environmental science & technologyVolume
53Issue
12Pagination
6729 - 6737Publisher
American Chemical SocietyLocation
Washington, D.C.Publisher DOI
ISSN
0013-936XeISSN
1520-5851Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2019, American Chemical SocietyUsage metrics
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No categories selectedKeywords
secondary organic aerosol (SOA)chemical compositionair qualityadverse human healthreactive oxygen species (ROS)oxidative potential (OP)Science & TechnologyTechnologyLife Sciences & BiomedicineEngineering, EnvironmentalEnvironmental SciencesEngineeringEnvironmental Sciences & EcologyPERSISTENT FREE-RADICALSOXYGEN SPECIES ROSPROFLUORESCENT NITROXIDESTROPOSPHERIC DEGRADATIONDITHIOTHREITOL DTTPARTICULATE MATTERFINE PARTICLESAIR-POLLUTIONVOLATILITYEMISSIONS
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