Chamber studies of secondary organic aerosol growth by reactive uptake of simple carbonyl compounds

Abstract

[1] Recent experimental evidence indicates that heterogeneous chemical reactions play an important role in the gas-particle partitioning of organic compounds, contributing to the formation and growth of secondary organic aerosol in the atmosphere. Here we present laboratory chamber studies of the reactive uptake of simple carbonyl species (formaldehyde, octanal, trans,trans-2,4-hexadienal, glyoxal, methylglyoxal, 2,3-butanedione, 2,4-pentanedione, glutaraldehyde, and hydroxyacetone) onto inorganic aerosol. Gas-phase organic compounds and aqueous seed particles (ammonium sulfate or mixed ammonium sulfate/sulfuric acid) are introduced into the chamber, and particle growth and composition are monitored using a differential mobility analyzer and an Aerodyne Aerosol Mass Spectrometer. No growth is observed for most carbonyls studied, even at high concentrations (500 ppb to 5 ppm), in contrast with the results from previous studies. The single exception is glyoxal (CHOCHO), which partitions into the aqueous aerosol much more efficiently than its Henry's law constant would predict. No major enhancement in particle growth is observed for the acidic seed, suggesting that the large glyoxal uptake is not a result of particle acidity but rather of ionic strength of the seed. This increased partitioning into the particle phase still cannot explain the high levels of glyoxal measured in ambient aerosol, indicating that additional (possibly irreversible) pathways of glyoxal uptake may be important in the atmosphere.

Distributions and diurnal changes of low molecular weight organic acids and ^|^alpha;-dicarbonyls in suburban aerosols collected at Mangshan, North China

“…α-Dicarbonyls showed concentrations ranging from 3.5 to 289 ng m -3 , with an arithmetical average of 51.5 ng m -3 in daytime and 59.8 ng m -3 in nighttime. Glyoxal (Gly) and methylglyoxal (MeGly) are gas-phase oxidation products of numerous VOCs such as benzene, toluene, xylene (Volkamer et al, 2001), ethylene (Ervens et al, 2004), isoprene (Zimmermann and Poppe, 1996) and terpene (Fick et al, 2004), and could act as precursors of secondary organic aerosols via heterogeneous processes (Kroll et al, 2005;Liggio et al, 2005).…”

Modeling of HCHO and CHOCHO at a semi-rural site in southern China during the PRIDE-PRD2006 campaign

“…HCHO oligomerization is also proposed to contribute to the partitioning of gaseous HCHO to aerosol phase (Toda et al, 2014). But, during a chamber study, Kroll et al (2005) did not find any growth of both neutral ((NH 4 ) 2 SO 4 ) and acidic (NH 4 HSO 4 ) aerosols in the presence of gaseous HCHO, suggesting that the uptake of HCHO by aerosols is unlikely taking place. Although numerical simulations of HCHO, either by multi-dimensional models or box models, can in some cases reproduce HCHO observations (Wagner et al, 2001;Fried et al, 2003b;MacDonald et al, 2012), significant discrepancies between modeled and measured HCHO concentration have been frequently found (Choi et al, 2010;Fried et al, 2011, and references therein).…”

“…As first indicated by Volkamer et al (2007), if loss of CHOCHO on aerosol surfaces is not taken into account, models can substantially overestimate measured CHOCHO concentrations. Laboratory studies found that uptake of CHOCHO by aerosols is mainly through polymerization process and is related with the acidity and the ionic strength within the aqueous phase of aerosols (Jang and Kamens, 2001;Liggio et al, 2005;Kroll et al, 2005). Once CHOCHO is taken up by aerosols, it can contribute to the formation of secondary organic aerosols (Volkamer et al, 2007;Tan et al, 2009;Washenfelder et al, 2011).…”

Mechanism of the Reaction of OH with Alkynes in the Presence of Oxygen

“…[5][6][7] (HCO) 2 is the simplest -dicarbonyl and its atmospheric significance stems from its role in aerosol formation, [8][9][10] and use as a marker of biogenic emission. 11,12 In addition, (HCO) 2 photochemistry is a recognised source of HOx (OH and HO 2 ) radicals in the troposphere.…”