Volatility of organic aerosol and its components in the megacity of Paris

Abstract

Abstract. Using a mass transfer model and the volatility basis set, we estimate the volatility distribution for the organic aerosol (OA) components during summer and winter in Paris, France as part of the collaborative project MEGAPOLI. The concentrations of the OA components as a function of temperature were measured combining data from a thermodenuder and an aerosol mass spectrometer (AMS) with Positive Matrix Factorization (PMF) analysis. The hydrocarbon-like organic aerosol (HOA) had similar volatility distributions for the summer and winter campaigns with half of the material in the saturation concentration bin of 10 µg m−3 and another 35–40 % consisting of low and extremely low volatility organic compounds (LVOCs with effective saturation concentrations C* of 10−3–0.1 µg m−3 and ELVOCs C* less or equal than 10−4 µg m−3, respectively). The winter cooking OA (COA) was more than an order of magnitude less volatile than the summer COA. The low-volatility oxygenated OA (LV-OOA) factor detected in the summer had the lowest volatility of all the derived factors and consisted almost exclusively of ELVOCs. The volatility for the semi-volatile oxygenated OA (SV-OOA) was significantly higher than that of the LV-OOA, containing both semi-volatile organic components (SVOCs with C* in the 1–100 µg m−3 range) and LVOCs. The oxygenated OA (OOA) factor in winter consisted of SVOCs (45 %), LVOCs (25 %) and ELVOCs (30 %). The volatility of marine OA (MOA) was higher than that of the other factors containing around 60 % SVOCs. The biomass burning OA (BBOA) factor contained components with a wide range of volatilities with significant contributions from both SVOCs (50 %) and LVOCs (30 %). Finally, combining the bulk average O : C ratios and volatility distributions of the various factors, our results are placed into the two-dimensional volatility basis set (2D-VBS) framework. The OA factors cover a broad spectrum of volatilities with no direct link between the average volatility and average O : C of the OA components.

Characterization of organic residues of size‐resolved fog droplets and their atmospheric implications

“…also section 3.2.3) [ Jimenez et al ., ]. However, the volatility and O/C relationship is very complex, and higher O/C does not always lead to lower volatility as reported in a few previous studies [ Tritscher et al ., ; Paciga et al ., ]. Volatility can be influenced by several other parameters like carbon number, molecular structures, and ambient conditions [ Kroll et al ., ; Tritscher et al ., ; Donahue et al ., ; Paciga et al ., ].…”

“…These findings indicate that in coarse droplet residues, the difference in volatility between remaining and evaporated organics cannot be explained by the O/C ratio and/or aging alone. This is not very surprising since several other factors apart from O/C can influence volatility of organics [ Tritscher et al ., ; Paciga et al ., ]. In addition, Altieri et al .…”

“…These findings indicate that in coarse droplet residues, the difference in volatility between remaining and evaporated organics cannot be explained by the O/C ratio and/or aging alone. This is not very surprising since several other factors apart from O/C can influence volatility of organics [Tritscher et al, 2011;Paciga et al, 2016]. In addition, Altieri et al [2008] have shown that higher molecular weight compounds and/or oligomers formed in cloud usually have lower O/C ratios than their monomeric parent compounds but are likely to be less volatile due to a higher number of carbon atoms [Jimenez et al, 2009].…”

Estimates of the organic aerosol volatility in a boreal forest using two independent methods

“…One of the key physicochemical properties of atmospheric organic compounds is their volatility, which determines their partitioning between the gas and particle phase (Pankow, 1994;Bilde et al, 2015). Atmospheric aerosol particles are mixtures of organic and inorganic compounds with different volatilities.…”

A technique for the measurement of organic aerosol hygroscopicity, oxidation level, and volatility distributions

“…The OA components could be separated into different groups using PMF with corresponding κ's, O : C ratios, and volatility distributions. This is similar to how Paciga et al (2016) used PMF on ambient OA in Paris and generated volatility distributions for each factor.…”