From Molecules to Droplets: The Fog and Aerosol Interaction Research Italy (FAIRARI) 2021/22 Campaign

Abstract The Italian Po Valley is one of the most polluted regions in Europe. During winter, meteorological conditions favor long and dense fogs, which strongly affect visibility and human health. In spring, the frequency of nighttime fogs reduces while daytime new particle formation events become more common. This transition is likely caused by a reduction in particulate matter (PM 2.5 ), leading to a decrease in the relevant condensation sink. The physics and chemistry of fog and aerosol have been studied at the San Pietro Capofiume site since the 1980s, but the detailed processes driving the observed trends are not fully understood. Hence, during winter and spring 2021/22, the Fog and Aerosol Interaction Research Italy (FAIRARI) campaign was carried out, using a wide spectrum of approaches, including in situ measurements, outdoor chamber experiments, and remote sensing. Atmospheric constituents and their properties were measured ranging from gas molecules and molecular clusters to fog droplets. One unique aspect of this study is the direct measurement of the aerosol composition inside and outside of fog, showing a slightly greater dominance of organic compounds in the interstitial compared to the droplet phase. Satellite observations of fog provided a spatial context and agreed well with in situ measurements of droplet size. They were complemented with in situ chamber experiments, providing insights into oxidative processes and revealing a large secondary organic aerosol-forming potential of ambient air upon chemical aging. The oxidative potential of aerosol and fog water inferred the impact of aerosol–fog interactions on particle toxicity. Significance Statement Aerosol and fog influence our climate and can have adverse effects on human health and visibility. Through anthropogenic emissions, such as from industry or transport, humans can influence the physical and chemical properties of fog and aerosol. The FAIRARI campaign investigated the formation of aerosols and aerosol–fog interactions in the Italian Po Valley, one of the most polluted regions in Europe. State-of-the-art experimental methods revealed the details of aerosols and fogs from the molecular level to the droplet scale. We observed a clear transition from winter to spring, with fog-dominated periods followed by an intensified secondary aerosol formation period. Organic and nitrate compounds dominated the composition of aerosol and fog residuals. The results will contribute to various aerosol–fog interaction modeling activities.

Authors

Institutions

Publication Details

Journal
Bulletin of the American Meteorological Society
Published
2024-12-06
DOI
https://doi.org/10.1175/bams-d-23-0166.1
Citations
4
Primary Topic
Atmospheric aerosols and clouds
Type
article
Field-Weighted Citation Impact
1.13
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

From Molecules to Droplets: The Fog and Aerosol Interaction Research Italy (FAIRARI) 2021/22 Campaign

Athanasios Nenes, Stefano Decesari, Sarah S. Steimer, Matteo Rinaldi et al.
4 citations
Bulletin of the American Meteorological Society
Atmospheric aerosols and clouds
1.13
article

From Molecules to Droplets: The Fog and Aerosol Interaction Research Italy (FAIRARI) 2021/22 Campaign

Athanasios Nenes, Stefano Decesari, Sarah S. Steimer, Matteo Rinaldi, Claudia Mohr, Yvette Gramlich, Angeliki Matrali, Radovan Krejčí, Sudhakar Dipu, Andreas Aktypis, Juha Kangasluoma, Liine Heikkinen, S. Fuzzi, Angela Marinoni, Fredrik Mattsson, Ilona Riipinen, Maurizio Busetto, Hendrik Andersen, Anil Kumar Patel, Sophie L. Haslett, Jing Yan Cai, Jorma Joutsensaari, Almuth Neuberger, Dominik Stolzenburg, Marco Paglione, Angelo Lupi, Darrel Baumgardner, Annica M. L. Ekman, Jan Čermák, Federico Bianchi, Christos Kaltsonoudis, Christina N. Vasilakopoulou, Juha Sulo, Spyros Ν. Pandis, Paul Zieger
article en
4 citations

Abstract

Abstract The Italian Po Valley is one of the most polluted regions in Europe. During winter, meteorological conditions favor long and dense fogs, which strongly affect visibility and human health. In spring, the frequency of nighttime fogs reduces while daytime new particle formation events become more common. This transition is likely caused by a reduction in particulate matter (PM 2.5 ), leading to a decrease in the relevant condensation sink. The physics and chemistry of fog and aerosol have been studied at the San Pietro Capofiume site since the 1980s, but the detailed processes driving the observed trends are not fully understood. Hence, during winter and spring 2021/22, the Fog and Aerosol Interaction Research Italy (FAIRARI) campaign was carried out, using a wide spectrum of approaches, including in situ measurements, outdoor chamber experiments, and remote sensing. Atmospheric constituents and their properties were measured ranging from gas molecules and molecular clusters to fog droplets. One unique aspect of this study is the direct measurement of the aerosol composition inside and outside of fog, showing a slightly greater dominance of organic compounds in the interstitial compared to the droplet phase. Satellite observations of fog provided a spatial context and agreed well with in situ measurements of droplet size. They were complemented with in situ chamber experiments, providing insights into oxidative processes and revealing a large secondary organic aerosol-forming potential of ambient air upon chemical aging. The oxidative potential of aerosol and fog water inferred the impact of aerosol–fog interactions on particle toxicity. Significance Statement Aerosol and fog influence our climate and can have adverse effects on human health and visibility. Through anthropogenic emissions, such as from industry or transport, humans can influence the physical and chemical properties of fog and aerosol. The FAIRARI campaign investigated the formation of aerosols and aerosol–fog interactions in the Italian Po Valley, one of the most polluted regions in Europe. State-of-the-art experimental methods revealed the details of aerosols and fogs from the molecular level to the droplet scale. We observed a clear transition from winter to spring, with fog-dominated periods followed by an intensified secondary aerosol formation period. Organic and nitrate compounds dominated the composition of aerosol and fog residuals. The results will contribute to various aerosol–fog interaction modeling activities.

Bulletin of the American Meteorological SocietyVol. 106(1)
Karlsruhe Institute of Technology (DE), University of Helsinki (FI), TU Wien (AT), University of California, Los Angeles (US), Stockholm University (SE), University of Patras (GR), University of Eastern Finland (FI), American Society for Photogrammetry and Remote Sensing (US), Paul Scherrer Institute (CH), ETH Zurich (CH), Institute of Atmospheric Sciences and Climate (IT), Droplet Measurement Technologies (United States) (US), University Hospital Leipzig (DE), National Research Council (IT), Bolin Centre for Climate Research (SE), École Polytechnique Fédérale de Lausanne (CH), Foundation for Research and Technology Hellas (GR), Leipzig University (DE)
Openalex Percentile: Top 22%
Atmospheric aerosols and clouds
1.13
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.