A kinetic mechanism for predicting secondary organic aerosol formation from toluene oxidation in the presence of NOx and natural sunlight

The formation, properties and impact of secondary organic aerosol: current and emerging issues

“…Glyoxal is formed during the photooxidation of biogenic and anthropogenic VOCs, is soluble in water (in form of the dihydrate) and can undergo hemiacetal/acetal formation. Therefore, several theoretical and experimental studies have been performed to evaluate the contribution of the C 2 -dialdehyde to SOA (Hastings et al, 2005;Kroll et al, 2005a;Liggio et al, 2005a, b;Loeffler et al, 2006;Offenberg et al, 2006;Carlton et al, 2007;Hu et al, 2007;Kua et al, 2008;Galloway et al, 2009;Nozière et al, 2009;Shapiro et al, 2009). Although all of these studies support the hypothesis that glyoxal oligomerization contributes to SOA, the MW (or MW distribution) of glyoxal oligomers has yet to be determined.…”

“…Nevertheless, for laboratory experiments several estimates have been made which indicate that, depending on the type of precursor, precursor concentrations and duration of the experiments, between 25 and 70% of the SOA mass can be made up of oligomeric products (Gao et al, 2004a, b;Kalberer et al, 2004;Dommen et al, 2006;Surratt et al, 2006;Hu et al, 2007;Müller et al, 2007). However, many of these estimates were made indirectly, e.g., based on a change of the volatility (increase of the remaining volume fraction after thermal treatment), and are therefore subject to a high level of uncertainty.…”

“…These schemes can account for multiple generations of oxidation and the progression of the volatility distribution as the generations unfold. Although no chemical transport model currently treats particle-phase reactions explicitly, these can be included as soon as a reasonable mechanism becomes available, and indeed some boxmodel simulations (for smog chambers) have begun exploring the importance of such reactions (Li et al, 2007;Capouet et al, 2008). More compact explicit model approaches (or surrogate schemes) have been designed for inclusion in 3-D atmospheric models, including CACM and derivatives (Griffin et al, 2002a(Griffin et al, , b, 2003(Griffin et al, , 2005Pun et al, 2002;Vutukuru et al, 2006;Chen et al, 2006Chen et al, , 2007, EMEP/Kam2(X) (Andersson-Sköld and Simpson, 2001;Simpson et al, 2007) and ORILAM-SOA (Tulet et al, 2006).…”

Early history and rationale for outdoor chamber work at the University of North Carolina

“…Sirakarn Leungsakul extended the a-pinene approach to D-limonene þ O 3 dark systems and NO x þ light systems. [57,58] This semi-explicit approach was then expanded to toluene by Di Hu et al, [59] and was later adapted in much simpler form by Kamens, Yang Zhou and Elias P. Rosen et al to toluene and xylene SOA systems, [60,61] with help from students Eric Chen, Rebecca Wilson and Katherine Galloway. The important discovery from the chamber experiments was that particle phase water could dramatically increase SOA formation from aromatics in the presence of background aerosols or ammonium sulfate seeds; the opposite was later observed for isoprene systems.…”

Mechanism reduction for the formation of secondary organic aerosol for integration into a 3-dimensional regional air quality model: <i>α</i>-pinene oxidation system

“…Several chemical mechanisms (Kamens et al, 1999;Colville and Griffin, 2004;Chen and Griffin, 2005;Leungsakul et al, 2005;Hu et al, 2007) have been proposed and evaluated against smog chamber studies for the SOA formation. Most of the comparisons focus on the model performance of the total SOA mass only.…”