Glyoxal-methylglyoxal cross-reactions in secondary organic aerosol formation.
Glyoxal (G) and methylglyoxal (MG) are potentially important secondary organic aerosol (SOA) precursors. Previous studies of SOA formation by G and MG have focused on either species separately; however, G and MG typically coexist in the atmosphere. We studied the formation of secondary organic material in aqueous aerosol mimic mixtures containing G and MG with ammonium sulfate. We characterized the formation of light-absorbing products using UV-vis spectrophotometry. We found that absorption at 280 nm can be described well using models for the formation of light-absorbing products by G and MG in parallel. Pendant drop tensiometry measurements showed that surface tension depression by G and MG in these solutions can be modeled as a linear combination of the effects of G and MG alone. Product species were identified using chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol CIMS). Peaks consistent with G-MG cross-reaction products were observed, accounting for a significant fraction of detected product mass, but most peaks could be attributed to self-reaction. We conclude that cross-reactions contribute to SOA mass from uptake of G and MG, but they are not required to accurately model the effects of this process on aerosol surface tension or light absorption.
Schwier
Allison N
AN
Department of Chemical Engineering, Columbia University, New York, New York 10027, USA.
Sareen
Neha
N
Mitroo
Dhruv
D
Shapiro
Erica L
EL
McNeill
V Faye
VF
D000042:Absorption; D000336:Aerosols / Q000737:chemistry*; D007700:Kinetics; D008027:Light; D013058:Mass Spectrometry; D011765:Pyruvaldehyde / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013500:Surface Tension; D013997:Time Factors; D014867:Water / Q000737:chemistry
D000336:Aerosols; D014867:Water; D011765:Pyruvaldehyde