Air liquid water Content (LWC) during the FAIRARI campaign, Po valley, Italy, February – April 2022
Marco Paglione, Matteo Rinaldi, Stefano Decesari, Karam Mansour
This dataset provides measurements of the liquid water content (LWC) of air collected at San Pietro Capofiume, northern Italy (44.65°N, 11.62°E, 11 m a.s.l.), from 1 February to 4 April 2022, during the Fog and Aerosol InteRAction Research Italy (FAIRARI) 2021/2022 campaign.
Liquid water content represents the mass of liquid water droplets suspended in a unit volume of air and is a key parameter for characterizing fog intensity and properties. It plays a central role in understanding fog activation mechanisms, persistence, aerosol and gas scavenging, and impacts on the atmospheric radiative budget.
The Po Valley is among the most polluted regions in Europe, and during winter it frequently experiences meteorological conditions that favor the formation of dense and long-lasting fog, with significant consequences for visibility and human health. Despite decades of research on fog and aerosol physics and chemistry conducted at the San Pietro Capofiume site since the 1980s, several processes controlling fog characteristics and long-term trends remain poorly understood.
The FAIRARI campaign was designed to address these knowledge gaps by investigating the interactions between fog and atmospheric aerosols, with the LWC measurements forming a fundamental component of this effort.
AtmosphereCloudsLiquid Water ContentLWCFogPo ValleyFAIRARI
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References
Neuberger A, Decesari S, Aktypis A, Andersen H, Baumgardner D, Bianchi F, Busetto M, Cai J, Cermak J, Dipu S, Ekman A, Fuzzi S, Gramlich Y, Haslett SL, Heikkinen L, Joutsensaari J, Kaltsonoudis C, Kangasluoma J, Krejci R, Lupi A, Marinoni A, Matrali A, Mattsson F, Mohr C, Nenes A, Paglione M, Pandis SN, Patel A, Riipinen I, Rinaldi M, Steimer SS, Stolzenburg D, Sulo J, Vasilakopoulou CN, Zieger P (2025) From Molecules to Droplets: The Fog and Aerosol Interaction Research Italy (FAIRARI) 2021/22 Campaign. Bulletin of the American Meteorological Society 106:E23–E50. https://doi.org/10.1175/bams-d-23-0166.1
Fuzzi S, Orsi G, Bonforte G, Zardini B, Franchini PL (1997) An Automated Fog Water Collector Suitable for Deposition Networks: Design, Operation and Field Tests. Water, Air, and Soil Pollution 93:383–394. https://doi.org/10.1023/a:1022108801083
Giulianelli L, Gilardoni S, Tarozzi L, Rinaldi M, Decesari S, Carbone C, Facchini MC, Fuzzi S (2014) Fog occurrence and chemical composition in the Po valley over the last twenty years. Atmospheric Environment 98:394–401. https://doi.org/10.1016/j.atmosenv.2014.08.080
Paglione M, Decesari S, Rinaldi M, Tarozzi L, Manarini F, Gilardoni S, Facchini MC, Fuzzi S, Bacco D, Trentini A, Pandis SN, Nenes A (2021) Historical Changes in Seasonal Aerosol Acidity in the Po Valley (Italy) as Inferred from Fog Water and Aerosol Measurements. Environmental Science & Technology 55:7307–7315. https://doi.org/10.1021/acs.est.1c00651
Data description
The data consists of one csv file with the following variables:
Date&timein the format YYYY-MM-DD HH:MM:SS (UTC+1)LWCAir liquid water content (g m⁻³)
Comments
Data collection
The air Liquid Water Content (LWC) was measured by a Particulate Volume Monitor PVM-100 (Gerber Scientific Inc.; Gerber et al. 1991) in terms of g/m³ with a time resolution of 1 min. The PVM was located in the middle of the measurement field of SPC, at approximately 1.5 m above the ground level, away from any direct obstacles.
Standardisation
In order to compensate the optical offset that increased during the measurement period, a baseline drift correction was applied to the LWC data using a line fitting procedure applied to the measurements carried out in clear sky (no fog) conditions.
Data correction
The correction factor of 1.72, used in previous publications about Po Valley’s fogs along the years (Fuzzi et al., 1997; Giulianelli et al., 2014; Paglione et al., 2021; Neuberger et al., 2025) is not applied in this dataset.
Additional comments
The PVM is used to activate the fog-collector when LWC exceeds 0.05 g m⁻³ (corresponding to 0.08 g m⁻³ when using the 1.72 correction factor, as used in previous publications for this site). This threshold corresponds to visibility of approximately 200 m and the fog is considered dense (the meteorological definition of fog is visibility less than 1 km).
Associated datasets
The current dataset is part of a collection of datasets from The fog and aerosol interaction research Italy (FAIRARI) campaign, November 2021 to May 2022.
Project
European Union’s Horizon 2020 research and innovation programme (Project FORCeS under Grant Agreement 821205)
Publisher
Bolin Centre Database
License
Open Data Commons Attribution License (ODC-By) v1.0
First name
Marco
Last name or organisation
Paglione
Email address
Address
Institute of Atmospheric Sciences and Climate (ISAC); National Research Council of Italy (CNR)
Postal code
IT-40129
City
Bologna
Province or state
Bologna (BO)
Country
Italy
GCMD science keyword
Earth science
GCMD location
Continent > Europe > Southern Europe > Italy
Dataset language
English
Begin date
2022-02-01
End date
2022-04-04