Oxidized organic molecules in the tropical free troposphere over Amazonia

Qiaozhi Zha; Diego Aliaga; Radovan Krejci; Victoria A Sinclair; Cheng Wu; Giancarlo Ciarelli; Wiebke Scholz; Liine Heikkinen; Eva Partoll; Yvette Gramlich; Wei Huang; Markus Leiminger; Joonas Enroth; Otso Peräkylä; Runlong Cai; Xuemeng Chen; Alkuin Maximilian Koenig; Fernando Velarde; Isabel Moreno; Tuukka Petäjä; Paulo Artaxo; Paolo Laj; Armin Hansel; Samara Carbone; Markku Kulmala; Marcos Andrade; Douglas Worsnop; Claudia Mohr; Federico Bianchi

doi:10.1093/nsr/nwad138

Oxidized organic molecules in the tropical free troposphere over Amazonia

Natl Sci Rev. 2023 May 15;11(1):nwad138. doi: 10.1093/nsr/nwad138. eCollection 2024 Jan.

Authors

Qiaozhi Zha^{1

2}, Diego Aliaga¹, Radovan Krejci³, Victoria A Sinclair¹, Cheng Wu⁴, Giancarlo Ciarelli¹, Wiebke Scholz⁵, Liine Heikkinen^{1

3}, Eva Partoll⁵, Yvette Gramlich³, Wei Huang¹, Markus Leiminger^{5

6}, Joonas Enroth¹, Otso Peräkylä¹, Runlong Cai¹, Xuemeng Chen¹, Alkuin Maximilian Koenig⁷, Fernando Velarde⁷, Isabel Moreno⁷, Tuukka Petäjä¹, Paulo Artaxo⁸, Paolo Laj^{1

9}, Armin Hansel⁵, Samara Carbone¹⁰, Markku Kulmala^{1

2

11}, Marcos Andrade^{7

12}, Douglas Worsnop^{1

13}, Claudia Mohr^{14

15}, Federico Bianchi¹

Affiliations

¹ Institute for Atmospheric and Earth System Research / Physics, University of Helsinki, Helsinki00014, Finland.
² Joint International Research Laboratory of Atmospheric and Earth System Sciences, Nanjing University, Nanjing210023, China.
³ Department of Environmental Science & Bolin Centre for Climate Research, Stockholm University, Stockholm, SE-106 91, Sweden.
⁴ Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg 40530, Sweden.
⁵ Institute for Ion and Applied Physics, University of Innsbruck, Innsbruck 6020, Austria.
⁶ Ionicon Analytik GmbH, Innsbruck 6020, Austria.
⁷ Laboratory for Atmospheric Physics, Institute for Physics Research, Universidad Mayor de San Andrés, La Paz, Bolivia.
⁸ Institute of Physics, University of Sao Paulo, Sao Paulo 05508-900, Brazil.
⁹ Institute for Geosciences and Environmental Research (IGE), University of Grenoble Alpes, Grenoble38000, France.
¹⁰ Agrarian Sciences Institute, Federal University of Uberlândia, Uberlândia 38408-100, Brazil.
¹¹ Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing100029, China.
¹² Department of Atmospheric and Oceanic Sciences, University of Maryland, College Park, MD 20742, USA.
¹³ Aerodyne Research, Inc., Billerica, MA01821, USA.
¹⁴ Department of Environmental System Science, ETH Zürich, Zürich 8092, Switzerland.
¹⁵ Switzerland and Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen 5232, Switzerland.

Abstract

New particle formation (NPF) in the tropical free troposphere (FT) is a globally important source of cloud condensation nuclei, affecting cloud properties and climate. Oxidized organic molecules (OOMs) produced from biogenic volatile organic compounds are believed to contribute to aerosol formation in the tropical FT, but without direct chemical observations. We performed in situ molecular-level OOMs measurements at the Bolivian station Chacaltaya at 5240 m above sea level, on the western edge of Amazonia. For the first time, we demonstrate the presence of OOMs, mainly with 4-5 carbon atoms, in both gas-phase and particle-phase (in terms of mass contribution) measurements in tropical FT air from Amazonia. These observations, combined with air mass history analyses, indicate that the observed OOMs are linked to isoprene emitted from the rainforests hundreds of kilometers away. Based on particle-phase measurements, we find that these compounds can contribute to NPF, at least the growth of newly formed nanoparticles, in the tropical FT on a continental scale. Thus, our study is a fundamental and significant step in understanding the aerosol formation process in the tropical FT.

Keywords: Amazon; free troposphere; oxidized organic molecules; tropical aerosol formation.