The cooling rate- and volatility-dependent glass-forming properties of organic aerosols measured by broadband dielectric spectroscopy

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DOI	Resolve DOI: https://doi.org/10.1021/acs.est.9b03317
Author	Search for: Zhang, Yue; Search for: Nichman, Leonid; Search for: Spencer, Peyton; Search for: Jung, Jason I.; Search for: Lee, Andrew; Search for: Heffernan, Brian K.; Search for: Gold, Avram; Search for: Zhang, Zhenfa; Search for: Chen, Yuzhi; Search for: Canagaratna, Manjula R.; Search for: Jayne, John T.; Search for: Worsnop, Douglas R.; Search for: Onasch, Timothy B.; Search for: Surratt, Jason D.; Search for: Chandler, David; Search for: Davidovits, Paul; Search for: Kolb, Charles E.
Format	Text, Article
Abstract	Glass transitions of secondary organic aerosols (SOA) from liquid/semisolid to solid phase states have important implications for aerosol reactivity, growth, and cloud formation properties. In the present study, glass transition temperatures (Tg) of isoprene SOA components, including isoprene hydroxy hydroperoxide (ISOPOOH), isoprene-derived epoxydiols (IEPOX), 2-methyltetrols, and 2-methyltetrol sulfates, were measured at atmospherically relevant cooling rates (2–10 K/min) by thin film broadband dielectric spectroscopy. The results indicate that 2-methyltetrol sulfates have the highest glass transition temperature, while ISOPOOH has the lowest glass transition temperature. By varying the cooling rate of the same compound from 2 to 10 K/min, the Tg of these compounds increased by 4–5 K. This temperature difference leads to a height difference of 400–800 m in the atmosphere for the corresponding updraft induced cooling rates, assuming a hygroscopicity value (κ) of 0.1 and relative humidity less than 95%. The Tg of the organic compounds was found to be strongly correlated with volatility, and a semiempirical formula between glass transition temperatures and volatility was derived. The Gordon–Taylor equation was applied to calculate the effect of relative humidity (RH) and water content at five mixing ratios on the Tg of organic aerosols. The model shows that Tg could drop by 15–40 K as the RH changes from <5 to 90%, whereas the mixing ratio of water in the particle increases from 0 to 0.5. These results underscore the importance of chemical composition, updraft rates, and water content (RH) in determining the phase states and hygroscopic properties of organic particles.
Publication date	2019-10-09
Publisher	American Chemical Society
In	Environmental Science & Technology 53, no. 21 (9 October 2019): 12366–12378.
Language	English
Peer reviewed	Yes
NRC publication	This is a non-NRC publication "Non-NRC publications" are publications authored by NRC employees prior to their employment by NRC.
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Record identifier	8eafc956-449e-412c-a826-d0f67ebbda2b
Record created	2019-10-22
Record modified	2021-04-26

Date modified:: 2024-04-19