University of Oulu

A. Casans, F. Rejano, J. Maldonado-Valderrama, J.A. Casquero-Vera, S. Ruiz-Peñuela, B.L. van Drooge, H. Lyamani, A. Cazorla, E. Andrews, Jack J. Lin, F. Mirza-Montoro, D. Pérez-Ramírez, F.J. Olmo, L. Alados-Arboledas, P. Cariñanos, G. Titos, Cloud condensation nuclei activation properties of Mediterranean pollen types considering organic chemical composition and surface tension effects, Atmospheric Environment, Volume 310, 2023, 119961, ISSN 1352-2310,

Cloud condensation nuclei activation properties of Mediterranean pollen types considering organic chemical composition and surface tension effects

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Author: Casans, A.1,2; Rejano, F.1,2; Maldonado-Valderrama, J.2,3;
Organizations: 1Andalusian Institute for Earth System Research IISTA, University of Granada, 18006, Granada, Spain
2Department of Applied Physics, University of Granada, 18071, Granada, Spain
3Unidad de Excelencia Internacional “Modeling Nature” (MNat), University of Granada, Spain
4Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
5Institute of Environmental Assessment and Water Research (IDAEA), CSIC, 08034, Barcelona, Spain
6Department of Applied Physics, University of Málaga, 29010, Málaga, Spain
7Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, 80309, United States
8Global Monitoring Laboratory, NOAA, Boulder, CO, 80305, United States
9Center for Atmospheric Research, University of Oulu, P.O. Box 4500, 90014, Oulu, Finland
10Institute of Geophysics, Faculty of Physics, University of Warsaw, 00-927, Warsaw, Poland
11Department of Botany, University of Granada, 18071, Granada, Spain
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.5 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-08-17


Wind-dispersed pollen grains emitted from vegetation are directly injected into the atmosphere being an important source of natural aerosols globally. These coarse particles of pollen can rupture into smaller particles, known as subpollen particles (SPPs), that may act as cloud condensation nuclei (CCN) and affect the climate. In this study, we characterize and investigate the ability of SPPs of 10 Mediterranean-climate pollen types to activate as CCN. A continuous flow CCN counter (CCNC) was used to measure the activation of size-selected (80, 100 and 200 nm dry mobility diameter) particles at different supersaturations (SS). Hygroscopicity parameter (κ) for each SPP type and size has been calculated using κ-Köhler theory. Organic chemical speciation and protein content has been determined to further characterize pollen solutions. Furthermore, the surface activity of SPPs has also been investigated by using pendant drop tensiometry. All studied SPP samples show critical supersaturation (SSCrit) values that are atmospherically relevant SS conditions. Hygroscopicity κ values are in the range characteristic of organic compounds (0.1–0.3). We found that organic speciation and protein content vary substantially among pollen types, with saccharides and fatty acids being the only organic compounds found in all pollen types. A clear relationship between SPP activation and its organic composition was not observed. This study also reveals that all SPPs investigated reduce the surface tension of water at high concentrations but at diluted concentrations (such as those of activation in the CCNC), the water surface tension value is a good approximation in Köhler theory. Overall, this analysis points out that pollen particles might be an important source of CCN in the atmosphere and should be considered in aerosol-cloud interactions processes.

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Series: Atmospheric environment
ISSN: 1352-2310
ISSN-E: 1873-2844
ISSN-L: 1352-2310
Volume: 310
Article number: 119961
DOI: 10.1016/j.atmosenv.2023.119961
Type of Publication: A1 Journal article – refereed
Field of Science: 1172 Environmental sciences
Funding: This work was supported by BioCloud project (RTI2018.101154.A.I00) funded by MCIN/AEI/10.13039/501100011033, FEDER “Una manera de hacer Europa” and NUCLEUS project (PID2021-128757OB-I00) funded by MCIN/AEI/10.13039/501100011033 and NextGenerationEU/PRTR. This work received support from the European Union's Horizon 2020 research and innovation program through projects ACTRIS.IMP (grant agreement No 871115) and ATMO_ACCESS (grant agreement No 101008004), by the Spanish Ministry of Science and Innovation through projects ELPIS (PID2020-120015RB-I00) and ACTRIS-España (CGL2017-90884REDT)). By the Junta de Andalucía Excellence, project ADPANE (P20-00136), AEROPRE (P-18-RT-3820) and by University of Granada Plan Propio through Visiting Scholars (PPVS2018-04), Singular Laboratory (LS2022-1) programs and Pre-Competitive Research Projects Pre-Greenmitigation3 (PP2022.PP34). Funding for open access charge, University of Granada/CBUA. Andrea Casans is funded by Spanish ministry of research and innovation under the predoctoral program FPI (PRE2019-090827) funded by MCIN/AEI/10.13039/501100011033, FSE “El FSE invierte en tu futuro”. Fernando Rejano is funded by Spanish ministry of universities through predoctoral grant FPU19/05340. Juan Andrés Casquero-Vera is funded by FJC2021-047873-I, MCIN/AEI/10.13039/501100011033 and NextGenerationEU/PRTR. Elisabeth Andrews is funded in part by NOAA cooperative agreements NA17OAR4320101.
Copyright information: © 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (