Skip to content

Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

by A. W H Chan, M. N. Chan, J. D. Surratt, P. S. Chhabra, C. L. Loza, J. D. Crounse, L. D. Yee, R. C. Flagan, P. O. Wennberg, J. H. Seinfeld show all authors
Atmospheric Chemistry and Physics ()
Get full text at journal

Abstract

Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene), the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA) via methacrolein (a C(4)-unsaturated aldehyde) under urban high-NO(x) conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN) as the important intermediate to isoprene and methacrolein SOA in this NO(x) regime. Here we show that as a result of this chemistry, NO(2) enhances SOA formation from methacrolein and two other alpha, beta-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NO(x) effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO(2)/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are alpha, beta-unsaturated and contain an additional methyl group on the alpha-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232) is insignificant, even under high-NO(2) conditions, as PAN (peroxy acyl nitrate, RC(O)OONO(2)) formation is structurally unfavorable. At atmospherically relevant NO(2)/NO ratios (3-8), the SOA yields from isoprene high-NO(x) photooxidation are 3 times greater than previously measured at lower NO(2)/NO ratios. At sufficiently high NO(2) concentrations, in systems of alpha, beta-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO(2) can exceed that from RO(2)+HO(2) reactions under the same inorganic seed conditions, making RO(2)+NO(2) an important channel for SOA formation.

Cite this document (BETA)

Authors on Mendeley

Readership Statistics

51 Readers on Mendeley
by Discipline
 
43% Environmental Science
 
27% Chemistry
 
20% Earth and Planetary Sciences
by Academic Status
 
33% Student > Ph. D. Student
 
29% Researcher
 
10% Professor
by Country
 
4% United States
 
2% United Kingdom
 
2% Belgium

Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Sign up & Download

Already have an account? Sign in