Hygroscopic behavior of individual NaNO3 particles
Item
Title (Dublin Core)
Hygroscopic behavior of individual NaNO3 particles
Description (Dublin Core)
Previous controversial studies on the hygroscopic behavior of NaNO<sub>3</sub> aerosols and our frequent observation of crystalline NaNO<sub>3</sub>-containing ambient aerosol particles prompted this extensive hygroscopic study on NaNO<sub>3</sub> aerosol particles. In this work, the hygroscopic behavior of individual NaNO<sub>3</sub> particles of 2.5–4.0 μm in diameter is investigated on a single-particle basis using an optical microscopy technique. Quite different hygroscopic behaviors between particles generated by the nebulization of NaNO<sub>3</sub> solution and powdery particles were observed; i.e., most of generated particles continuously grew and shrank during humidifying and dehydration processes, respectively, and yet all the individual powdery particles had reproducible deliquescence and efflorescence relative humidities (DRHs and ERHs). The different behaviors of the two NaNO<sub>3</sub> systems are due to the different nucleation mechanisms. Our hygroscopic studies of NaNO<sub>3</sub> particles generated from aqueous NaNO<sub>3</sub> solutions indicate that they nucleate via homogeneous nucleation, but the time scale for the nucleation to occur is too long to be atmospherically relevant. And thus no efflorescence of the particles has been observed in the laboratory measurements. However, when chemical species acting as heterogeneous nuclei are present, then efflorescence occurs which can explain the observation of ambient crystalline NaNO<sub>3</sub> particles. It is imperative to work with heterogeneous nucleation systems which are more relevant to the real world.
Creator (Dublin Core)
Lee, M.-J.
Jung, H.-J.
Eom, H.-J.
Maskey, S.
Kim, H. K.
Ro, C.-U.
Date (Dublin Core)
2018-08-11
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acpd-11-23203-2011
https://acp.copernicus.org/preprints/acp-2011-663/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
