EGU21-6310, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-6310
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Nano-HTDMA for investigating hygroscopic properties of sub-10 nm aerosol nanoparticles

Ting Lei1,2, Nan Ma1,4,3, Juan Hong1,4, Thomas Tuch3, Xin Wang2, Zhibin Wang5, Mira Pöhlker2, Maofa Ge6, Weigang Wang6, Eugene Mikhailov7, Thorsten Hoffmann8, Ulrich Pöschl2, Hang Su2, Alfred Wiedensohler3, and Yafang Cheng1
Ting Lei et al.
  • 1Minerva Research Group, Max Planck Institute for Chemistry, Mainz, Germany (yafang.cheng@mpic.de, nan.ma@jnu.edu.cn, ting.lei@mpic.de)
  • 2Max-Plank-Institute for Chemistry, Multiphase Chemistry department, Mainz, Germany (u.poschl@mpic.de, h.su@mpic.de, m.pohlker@mpic.de, ting.lei@mpic.de)
  • 3Leibniz Institute for Tropospheric Research, Leipzig, Germany (thomas.tuch@tropos.de, ali@tropos.de, nan.ma@jnu.edu.cn)
  • 4Institute for Environmental and Climate Research, Jinan University, Guangzhou, China (nan.ma@jnu.edu.cn, juanhong0108@jnu.edu.cn)
  • 5Reserch Center for Air Pollution and Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China (wangzhibin@zju.edu.cn)
  • 6Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, P. R. China (gemaofa@iccas.ac.cn, wangwg@iccas.ac.cn)
  • 7St. Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, Russia (eugene.mikhailov@paloma.spbu.ru)
  • 8Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany (hoffmant@uni-mainz.de)

Interactions between water and nanoparticles are of great significance for atmospheric multiphase processes, physical chemistry, and materials science. Current knowledge of the hygroscopic and related physicochemical properties of nanoparticles, however, is insufficient due to limitations of the available measurement techniques. Here, we present the design and performance of a nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA) apparatus. To enable high accuracy and precision in hygroscopicity measurements of sub-10 nm aerosol nanoparticles, systematic and comprehensive calibration criteria of nano-HTDMA have been developed and applied, including sheath/aerosol flow rates, DMA voltage, relative humidity (RH) sensor, temperature sensor, and particle sizing. After calibration, the nano-HTDMA system has been shown to have an accurate sizing and a small sizing offsets between the two DMAs (<1.4%) for aerosol nanoparticles with diameters down to 6 nm. Moreover, to maintain the RH-uniformities that prevent the pre-deliquescence and non-prompt phase transition of nanoparticles within DMA2, the RH of sheath flow is kept as same as that of aerosol flow at inlet of DMA2, and the humidification system and the DMA2 system are placed in a well-insulated and air conditioner housing (±0.1K). Using nano-HTDMA system. We investigate the hygroscopic behavior of aerosol nanoparticles of two inorganic substances (e.g., ammonium sulfate and sodium sulfate). A strong size dependence of the hygroscopic growth factor is observed for ammonium sulfate and sodium sulfate nanoparticles with diameters down to 6 nm, respectively. For size dependence of phase transition, we find a weak size dependence of DRH and ERH of ammonium sulfate nanoparticles with diameters from 6 to 100 nm but a pronounced size dependence of DRH and ERH between 20 and  6 nm for sodium sulfate nanoparticles.

How to cite: Lei, T., Ma, N., Hong, J., Tuch, T., Wang, X., Wang, Z., Pöhlker, M., Ge, M., Wang, W., Mikhailov, E., Hoffmann, T., Pöschl, U., Su, H., Wiedensohler, A., and Cheng, Y.: Nano-HTDMA for investigating hygroscopic properties of sub-10 nm aerosol nanoparticles, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6310, https://doi.org/10.5194/egusphere-egu21-6310, 2021.

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