14 Dec 2022
14 Dec 2022

Measurement report: Molecular-level investigation of atmospheric cluster ions at the tropical high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes

Qiaozhi Zha1, Wei Huang1, Diego Aliaga1, Otso Peräkylä1, Liine Heikkinen2, Alkuin Maximilian Koenig3, Cheng Wu4, Joonas Enroth1, Yvette Gramlich2, Jing Cai1, Samara Carbone5, Armin Hansel6, Tuukka Petäjä1, Markku Kulmala1,7,8, Douglas Worsnop1,9, Victoria Sinclair1, Radovan Krejci2, Marcos Andrade10,11, Claudia Mohr2, and Federico Bianchi1 Qiaozhi Zha et al.
  • 1Institute for Atmospheric and Earth System Research /Physics, University of Helsinki, Helsinki, Finland
  • 2Department of Environmental Science & Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
  • 3Institut des Géosciences de l'Environnement, Univ Grenoble Alpes, CNRS, IRD, Grenoble INP, Grenoble, France
  • 4Department of Chemistry & Molecular Biology, University of Gothenburg, Sweden
  • 5Federal University of Uberlândia, Uberlândia, MG, Brazil
  • 6Institute for Ion and Applied Physics, University of Innsbruck, Innsbruck, Austria
  • 7Joint International Research Laboratory of Atmospheric and Earth System Sciences, Nanjing University, Nanjing, China
  • 8Aerosol and Haze Laboratory, Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, China
  • 9Aerodyne Research, Inc., Billerica, MA, USA
  • 10Laboratory for Atmospheric Physics, Institute for Physics Research, Universidad Mayor de San Andrés, La Paz, Bolivia
  • 11Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, MD, 25 USA

Abstract. Air ions are the key components for a series of atmospheric physicochemical interactions, such as ion-catalyzed reactions, ion-molecule reactions, and ion-induced new particle formation. They also control atmospheric electrical properties with effects on global climate. We performed molecular-level measurements of cluster ions at the high-altitude research station Chacaltaya (CHC; 5240 m a.s.l.), located in the Bolivian Andes, from January to May 2018 using an atmospheric pressure interface time-of-flight mass spectrometer. The negative ions mainly consisted of (H2SO4)0–3•HSO4, (HNO3)0–2•NO3, SO5, (NH3)1–6•(H2SO4)3–7•HSO4, malonic acid-derived, and CHO/CHON•(HSO4/NO3) cluster ions. Their temporal variability exhibited distinct diurnal and seasonal patterns due to the changes in the corresponding neutral species’ molecular properties (such as electron affinity and proton affinity) and concentrations resulting from the air masses arriving at CHC from different source regions. The positive ions were mainly composed of protonated amines and organic cluster ions, but exhibited no clear diurnal variation. H2SO4-NH3 cluster ions likely contributed to the new particle formation process, particularly during wet-to-dry transition period and dry season when CHC was more impacted by air masses originating from source regions with elevated SO2 emissions. Our study provides new insights into the chemical composition of atmospheric cluster ions and their role in new particle formation in the high-altitude mountain environment of the Bolivian Andes.

Qiaozhi Zha et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1182', Anonymous Referee #1, 04 Jan 2023
  • RC2: 'Comment on egusphere-2022-1182', Anonymous Referee #2, 20 Jan 2023

Qiaozhi Zha et al.

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Figure data of "Measurement report: Molecular-level investigation of atmospheric cluster ions at the tropical high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes" Qiaozhi Zha

Qiaozhi Zha et al.


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Short summary
We investigate the chemical composition of atmospheric cluster ions from Jan to May 2018 at high-altitude research station Chacaltaya (5240 m a.s.l.) in the Bolivian Andes. Combined with state-of-the-art mass spectrometers and air mass history analysis, the measured cluster ions exhibited distinct diurnal and seasonal patterns, some of which contributed to new particle formation. Our study will improve the understanding of atmospheric ions and their role in high-altitude new particle formation.