@article{saha_khlystov_yahya_zhang_xu_ng_grieshop_2017, title={Quantifying the volatility of organic aerosol in the southeastern US}, volume={17}, number={1}, journal={Atmospheric Chemistry and Physics}, author={Saha, P. K. and Khlystov, A. and Yahya, K. and Zhang, Y. and Xu, L. and Ng, N. L. and Grieshop, A. P.}, year={2017}, pages={501–520} }
 @article{saha_grieshop_2016, title={Exploring Divergent Volatility Properties from Yield and Thermodenuder Measurements of Secondary Organic Aerosol from alpha-Pinene Ozonolysis}, volume={50}, ISSN={["1520-5851"]}, DOI={10.1021/acs.est.6b00303}, abstractNote={There are large uncertainties in the parameters dictating the gas-particle partitioning of secondary organic aerosols (SOA), although this process has major influences on their atmospheric lifecycle. Here, we extract parameters that describe the partitioning of SOA from α-pinene ozonolysis using measurements from a dual-thermodenuder (TD) system that constrains both the equilibrium and the kinetic properties that dictate SOA phase partitioning. Parallel TDs that vary in temperature and residence time were used with an evaporation-kinetics model to extract parameter values. An evaporation coefficient of an order of 0.1 best describes the observed evaporation, suggesting equilibration time scales of atmospheric SOA on the order of minutes to hours. A total of 20-40% of SOA mass consists of low-volatility material (saturation concentration of <0.3 μg m(-3)) in the TD-derived SOA volatility distribution. While distinct from existing parametrizations from aerosol growth experiments, derived values are consistent with recent observations of slow room-temperature evaporation of SOA and contributions from extremely low volatility organic compounds formed during α-pinene ozonolysis. The volatility parameters thus determined suggest that SOA yields and enthalpies of evaporation are substantially higher, and products less volatile, than is currently assumed in atmospheric models. These results will help improve the representation of SOA in air-quality and climate models.}, number={11}, journal={ENVIRONMENTAL SCIENCE & TECHNOLOGY}, author={Saha, Provat K. and Grieshop, Andrew P.}, year={2016}, month={Jun}, pages={5740–5749} }
 @article{saha_khlystov_grieshop_2015, title={Determining Aerosol Volatility Parameters Using a "Dual Thermodenuder" System: Application to Laboratory-Generated Organic Aerosols}, volume={49}, ISSN={["1521-7388"]}, DOI={10.1080/02786826.2015.1056769}, abstractNote={Thermodenuders (TD) are a tool widely used for measuring aerosol volatility in the laboratory and field. Extracting the parameters that dictate organic aerosol volatility from TD data is challenging because gas-particle partitioning rarely reaches equilibrium inside a TD operating under atmospheric conditions, thus a wide variety of parameter sets can explain observed evaporation. Component volatilities (as represented by saturation vapor pressure, Csat), cannot be directly extracted due to uncertainties in potential limitations to mass transfer (represented by mass accommodation coefficient, α) and components’ enthalpies of evaporation (ΔHvap). To address these limitations, we have developed a “dual TD” experimental approach in which one line uses a temperature-stepping TD (TS-TD) with a relatively long residence time (RT) and the other operates isothermally at variable residence time (VRT-TD). Data from this approach are used in tandem with an optimizing evaporation kinetics model to extract the values of parameters dictating volatility (Csat, and associated values of ΔHvap and α). The system was evaluated using laboratory generated dicarboxylic acid aerosols (adipic acid and succinic acid). Excellent agreement with previously published evaporation data collected with other TD systems was observed. Parameter values reported in the literature for the tested acids vary widely, but our results are generally consistent with those from studies that allow for nonunity values of α. For example, our results suggest that α for these aerosols are of order 0.1, in agreement with results determined by Saleh et al. (2009, 2012). Modeling results suggest that the addition of VRT-TD data provides tighter constraint on feasible ΔHvap and α values. The dual TD approach presented here does not rely on equilibration in the TD and thus can be directly applied to extract volatility parameters for more complex laboratory and ambient organic aerosol systems. Copyright 2015 American Association for Aerosol Research}, number={8}, journal={AEROSOL SCIENCE AND TECHNOLOGY}, author={Saha, Provat K. and Khlystov, Andrey and Grieshop, Andrew P.}, year={2015}, month={Aug}, pages={620–632} }