Articles | Volume 26, issue 9
https://doi.org/10.5194/acp-26-6521-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-26-6521-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
15 May 2026
Research article |
| 15 May 2026
| 15 May 2026
Ventilation and low pollution enhancing new particle formation in Milan, Italy
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Manuel Bettineschi
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Silvia Melina
Department of Chemistry, University of Milan, 20133, Milan, Italy
now at: Ecogeo s.r.l., 24122, Bergamo, Italy
Diego Aliaga
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
now at: Department of Environmental Science, Stockholm University, 10691, Stockholm, Sweden
now at: Bolin Centre for Climate Research, Stockholm University, 10691, Stockholm, Sweden
Andrea Bergomi
Department of Chemistry, University of Milan, 20133, Milan, Italy
Beatrice Biffi
Air Quality Department, Regional Agency for Environmental Protection of Lombardy, 20124, Milan, Italy
Alessandro Bigi
Department of Engineering, University of Modena and Reggio Emilia, 41125, Modena, Italy
Giancarlo Ciarelli
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Cristina Colombi
Air Quality Department, Regional Agency for Environmental Protection of Lombardy, 20124, Milan, Italy
Paola Fermo
Department of Chemistry, University of Milan, 20133, Milan, Italy
Ivan Grigioni
Department of Chemistry, University of Milan, 20133, Milan, Italy
Veli-Matti Kerminen
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Markku Kulmala
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Janne Lampilahti
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Angela Marinoni
Institute of Atmospheric Sciences and Climate, National Research Council of Italy, 40129, Bologna, Italy
Celestine Oliewo
Department of Engineering, University of Modena and Reggio Emilia, 41125, Modena, Italy
Scuola Universitaria Superiore IUSS, 27100, Pavia, Italy
Juha Sulo
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
now at: School of Earth and Atmospheric Sciences, Queensland University of Technology, 4001, Brisbane, Australia
Gianluigi Valli
Department of Physics, University of Milan, 20133, Milan, Italy
Roberta Vecchi
Department of Physics, University of Milan, 20133, Milan, Italy
Tuukka Petäjä
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Katrianne Lehtipalo
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Atmospheric Composition Research, Finnish Meteorological Institute, 00101, Helsinki, Finland
Federico Bianchi
CORRESPONDING AUTHOR
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, 00014, Helsinki, Finland
Data sets
Data of "Ventilation and low pollution enhancing new particle formation in Milan, Italy" Myriam Agrò https://doi.org/10.5281/zenodo.18130252
Short summary
This study investigates new particle formation (NPF) in Milan, the most populated city in the Po Valley (Italy), using one year of particle number size distribution data (1.2–480 nm). NPF is enhanced under cleaner air conditions with lower pollution, reduced condensation sink, stronger ventilation, and stronger northwesterly winds (e.g., Foehn events). In contrast, longer air mass residence time in the Po Valley and higher air mass exposure to anthropogenic emissions suppress it.
This study investigates new particle formation (NPF) in Milan, the most populated city in the Po...
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