Secondary organic aerosol production from pinanediol, a semi-volatile surrogate for first-generation oxidation products of monoterpenes

Abstract

Abstract. We have investigated the production of secondary organic aerosol (SOA) from pinanediol (PD), a precursor chosen as a semi-volatile surrogate for first-generation oxidation products of monoterpenes. Observations at the CLOUD facility at CERN have shown that oxidation of organic compounds such as PD can be an important contributor to newparticle formation. Here we focus on SOA mass yields and chemical composition from PD photo-oxidation in the CMU smog chamber. To determine the SOA mass yields from this semi-volatile precursor, we had to address partitioning of both the PD and its oxidation products to the chamber walls. After correcting for these losses, we found OA loading dependent SOA mass yields from PD oxidation that ranged between 0.1 and 0.9 for SOA concentrations between 0.02 and 20 µg m −3 , these mass yields are 2-3 times larger than typical of much more volatile monoterpenes. The average carbon oxidation state measured with an aerosol mass spectrometer was around −0.7. We modeled the chamber data using a dynamical two-dimensional volatility basis set and found that a significant fraction of the SOA comprises low-volatility organic compounds that could drive new-particle formation and growth, which is consistent with the CLOUD observations.

Molecular understanding of new-particle formation from α-pinene between −50 and +25 °C

“…However, experimentally derived volatilities from desorption thermograms measured with a FIGAERO (Filter Inlet for Gases and AEROsols) show a good agreement with the combination of semiempirical methods and theoretical model calculations (Lopez-Hilfiker et al, 2014;Schobesberger et al, 2018). This was recently verified in a complementary study of the α-pinene ozonolysis products examined here (Ye et al, 2019), in which the volatility distribution of molecules in the nucleated particles, measured with a FIGAERO inlet over a wide range of temperatures, is in good agreement with those estimated by Stolzenburg et al (2018).…”

“…be observed as temperature decreases. This decrease in O/C ratio with decreasing temperature was also observed in the particle phase by Kristensen et al (2017) and Ye et al (2019) and raises the question of the extent to which the reduction in oxidation also affects NPF.…”

“…It was shown that the steep exponential temperature dependence in the saturation vapor pressure, as described by the Clausius-Clapeyron relation, counters the reduction in the oxidation state in terms of their volatility distribution. Recent measurements of particle composition by Ye et al (2019) showed that this leads to sufficient condensation of even the low-oxygenated and moderately oxygenated organic products at low temperatures. The volatility of the oxidation products is relevant in order to characterize their ability to condense and participate in NPF.…”

Peroxy radical chemistry and the volatility basis set

“…Third, the large majority of organic oxidation products are likely to be oxygenated species with lower vapor pressure than the precursors that remain in the gas phase (traditional SVOCs). Later-generation chemistry of these products remains an important topic that cannot be forgotten (Donahue et al, 2005(Donahue et al, , 2012a; these subsequent steps have already been shown to be efficient sources of HOMs (Schobesberger et al, 2013;Ye et al, 2018).…”

Peroxy Radical Chemistry and the Volatility Basis Set

“…Third, the large majority of organic oxidation products are likely to be oxygenated species with lower vapor pressure than the precursor that remain in the gas phase ("traditional" SVOCs). Later-generation chemistry of these products remains an 5 important topic that can not be forgotten (Donahue et al, 2005(Donahue et al, , 2012a; these subsequent steps have already been shown to themselves be efficient sources of HOMs (Schobesberger et al, 2013;Ye et al, 2018).…”