Aerosol spectral optical properties in the Paris urban area and its peri-urban and forested surroundings during summer 2022 from ACROSS surface observations

Abstract. The complex refractive index (CRI; n−ik) and the single scattering albedo (SSA) are key parameters driving the aerosol direct radiative effect. Their spatial, temporal, and spectral variabilities in anthropogenic–biogenic mixed environments are poorly understood. In this study, we retrieve the spectral CRI and SSA (370–950 nm wavelength range) from in situ surface optical measurements and the number size distribution of submicron aerosols at three sites in the greater Paris area, representative of the urban city, as well as its peri-urban and forested rural environments. Measurements were taken as part of the ACROSS (Atmospheric Chemistry of the Suburban Forest) campaign in June–July 2022 under diversified conditions: (1) two heatwaves leading to high aerosol levels, (2) an intermediate period with low aerosol concentrations, and (3) an episode of long-range-transported fire emissions. The retrieved CRI and SSA exhibit an urban-to-rural gradient, whose intensity is modulated by the weather conditions. A full campaign average CRI of 1.41−0.037i (urban), 1.52−0.038i (peri-urban), and 1.50−0.025i (rural) is retrieved. The imaginary part of the CRI (k) increases and the SSA decreases at the peri-urban and forest sites when exposed to the influence of the Paris urban plume. Values of k > 0.1 and SSA < 0.6 at 520 nm are related to a black carbon mass fraction larger than 10 %. Organic aerosols are found to contribute to more than 50 % of the aerosol mass and up to 10 % (urban), 17 % (peri-urban), and 22 % (forest) of the aerosol absorption coefficient at 370 nm. A k value of 0.022 (370 nm) was measured at the urban site for the long-range-transported fire episode.

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Journal
Atmospheric chemistry and physics
Published
2025-03-14
DOI
https://doi.org/10.5194/acp-25-3161-2025
Citations
2
Primary Topic
Atmospheric chemistry and aerosols
Type
article
Field-Weighted Citation Impact
2.60

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article

Aerosol spectral optical properties in the Paris urban area and its peri-urban and forested surroundings during summer 2022 from ACROSS surface observations

Ludovico Di Antonio, Olivier Favez, Antonin Bergé, Servanne Chevaillier et al.
2 citations
Atmospheric chemistry and physics
Atmospheric chemistry and aerosols
2.60
article

Aerosol spectral optical properties in the Paris urban area and its peri-urban and forested surroundings during summer 2022 from ACROSS surface observations

Ludovico Di Antonio, Olivier Favez, Antonin Bergé, Servanne Chevaillier, Joël Brito, Griša Močnik, Pascal Zapf, Laurent Poulain, Prodip Acharja, Shravan Deshmukh, Gilles Forêt, Éric Villenave, Aline Gratien, Claudia Di Biagio, Guillaume Siour, Véronique Riffault, Jean‐Eudes Petit, Patrice Coll, Paola Formenti, Matthias Beekmann, Jean‐François Doussin, Astrid Bauville, Lelia N. Hawkins, Barbara D’Anna, Julien Kammer, Mathieu Cazaunau, Vincent Michoud, Brigitte Language, Cécile Gaimoz, Franck Maisonneuve, Juliette R. Dignum, C. A. Cantrell, Pauline Pouyes, Kanuri I. Roundtree, David O. De Haan, Manuela Cirtog, Pierre‐Marie Flaud, Émilie Perraudin, Eva Drew Pronovost, Marwa Shahin
article en
2 citations

Abstract

Abstract. The complex refractive index (CRI; n−ik) and the single scattering albedo (SSA) are key parameters driving the aerosol direct radiative effect. Their spatial, temporal, and spectral variabilities in anthropogenic–biogenic mixed environments are poorly understood. In this study, we retrieve the spectral CRI and SSA (370–950 nm wavelength range) from in situ surface optical measurements and the number size distribution of submicron aerosols at three sites in the greater Paris area, representative of the urban city, as well as its peri-urban and forested rural environments. Measurements were taken as part of the ACROSS (Atmospheric Chemistry of the Suburban Forest) campaign in June–July 2022 under diversified conditions: (1) two heatwaves leading to high aerosol levels, (2) an intermediate period with low aerosol concentrations, and (3) an episode of long-range-transported fire emissions. The retrieved CRI and SSA exhibit an urban-to-rural gradient, whose intensity is modulated by the weather conditions. A full campaign average CRI of 1.41−0.037i (urban), 1.52−0.038i (peri-urban), and 1.50−0.025i (rural) is retrieved. The imaginary part of the CRI (k) increases and the SSA decreases at the peri-urban and forest sites when exposed to the influence of the Paris urban plume. Values of k > 0.1 and SSA < 0.6 at 520 nm are related to a black carbon mass fraction larger than 10 %. Organic aerosols are found to contribute to more than 50 % of the aerosol mass and up to 10 % (urban), 17 % (peri-urban), and 22 % (forest) of the aerosol absorption coefficient at 370 nm. A k value of 0.022 (370 nm) was measured at the urban site for the long-range-transported fire episode.

Atmospheric chemistry and physicsVol. 25(5)
École de l'air et de l'espace (FR), Centre National de la Recherche Scientifique (FR), Harvey Mudd College (US), Université de Bordeaux (FR), École Pratique des Hautes Études (FR), University of San Diego (US), University of Oslo (NO), University of Nova Gorica (SI), Université de Versailles Saint-Quentin-en-Yvelines (FR), Université Paris-Est Créteil (FR), Université Paris Cité (FR), Institut Mines-Télécom (FR), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), North-West University (ZA), Université Paris-Saclay (FR), Paris-Est Sup (FR), Sorbonne Université (FR), Atmosphere Systems and Services (FR), Environnements et Paléoenvironnements Océaniques et Continentaux (FR), Institut Pierre-Simon Laplace (FR), Leibniz Institute for Tropospheric Research (DE), Laboratoire des Sciences du Climat et de l'Environnement (FR), Institut national de l'environnement industriel et des risques (FR), CEA Paris-Saclay (FR), Centre d'Enseignement et de Recherche en Environnement Atmosphérique (FR), Laboratoire Interuniversitaire des Systèmes Atmosphériques (FR), Centre Inria de l'Université de Lille (FR), Institut National des Sciences de l'Univers (FR), Laboratoire atmosphères, milieux, observations spatiales (FR), Laboratoire de Chimie Bactérienne (FR), Laboratoire Techniques, Territoires et Sociétés (FR)
National Science Foundation, European Commission, Agence Nationale de la Recherche, Centre National de la Recherche Scientifique, Grand Équipement National De Calcul Intensif, Institut national des sciences de l'Univers
Openalex Percentile: Top 13%
Atmospheric chemistry and aerosols
2.60
DOIOpen Access PDFOpenAlex
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