EGU22-788
https://doi.org/10.5194/egusphere-egu22-788
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Effects of heterogeneous reaction with NO2 on ice nucleation activities of feldspar and Arizona Test Dust

Lanxiadi Chen1, Chao Peng1, Jingchuan Chen2, Jie Chen2, Zhijun Wu2, and Mingjin Tang1
Lanxiadi Chen et al.
  • 1Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China
  • 2College of Environmental Sciences and Engineering, Peking University, Beijing, China

Mineral dust is an important type of ice nucleating particles in the troposphere; however, the effects of heterogeneous reactions on ice nucleation (IN) activities of mineral dust remain to be elucidated. A droplet-freezing apparatus (Guangzhou Institute of Geochemistry Ice Nucleation Apparatus, GIGINA) was developed in this work to measure IN activities of atmospheric particles in the immersion freezing mode, and its performance was validated by a series of experimental characterizations. This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust (ATD) particles before and after heterogeneous reaction with NO2 (10±0.5 ppmv) at 40% relative humidity. The fractional surface coverage of nitrate, θ(NO3-), increased to 3.1±0.2 for feldspar after reaction with NO2 for 6 h, and meanwhile the active site density per unit surface area (ns) at -20 oC was reduced from 92±5 to <1.0cm-2 by about two orders of magnitude; however, no changes in nitrate content or IN activities were observed for further increase in reaction time (up to 24 h). Both nitrate content and IN activities changed continuously with reaction time (up to 24 h) for ATD particles; after reaction with NO2 for 24 h, θ(NO3-) increased to 1.4±0.1 and ns at -20 oC was reduced from 20±4 to 9.7±1.9 cm-2 by a factor of ~2. Our work suggests that heterogeneous reaction with NO2 may significantly reduce IN activities of mineral dust in the immersion freezing mode.

How to cite: Chen, L., Peng, C., Chen, J., Chen, J., Wu, Z., and Tang, M.: Effects of heterogeneous reaction with NO2 on ice nucleation activities of feldspar and Arizona Test Dust, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-788, https://doi.org/10.5194/egusphere-egu22-788, 2022.