In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter

Abstract. Vertical in situ measurements of aerosols and trace gases were conducted in Fairbanks, Alaska, during winter 2022 as part of the Alaskan Layered Pollution and Chemical Analysis campaign (ALPACA). Using a tethered balloon, the study explores the dispersion of pollutants in the continental high-latitude stable boundary layer (SBL). Analysis of 24 flights revealed a stratified SBL structure with different pollution layers in the lowest tens of meters of the atmosphere, offering unprecedented detail. Surface emissions generally accumulated in a surface mixing layer (ML) extending to an average of 51 m, with a well-mixed sublayer (MsL) reaching 22 m. The height and concentrations within the ML were strongly influenced by a local wind driven by nearby topography under anticyclonic conditions. During strong radiative cooling, a drainage flow increased turbulence near the surface, altering the temperature profile and deepening the ML. Above the ML, pollution concentrations decreased but showed clear signs of freshly released anthropogenic emissions. Higher in the atmosphere, above elevated inversions, pollution levels were similar to previously reported Arctic haze concentrations, even though Fairbanks' outflow concentrations below elevated inversions were up to 6 times higher, likely due to power plant emissions. In situ measurements indicated that gas and particle tracer ratios in elevated power plant plumes differed significantly from those near the surface. Overall, pollution layers were strongly correlated with the temperature stratification and emission heights, emphasizing the need for improved representation of temperature inversions and emission sources in air quality models to enhance pollution forecasts.

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Publication Details

Journal
Atmospheric chemistry and physics
Published
2025-03-27
DOI
https://doi.org/10.5194/acp-25-3687-2025
Citations
6
Primary Topic
Atmospheric chemistry and aerosols
Type
article
Field-Weighted Citation Impact
7.80

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article

In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter

Antonio Donateo, Stefano Decesari, William Robert Simpson, S. R. Arnold et al.
6 citations
Atmospheric chemistry and physics
Atmospheric chemistry and aerosols
7.80
article

In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter

Antonio Donateo, Stefano Decesari, William Robert Simpson, S. R. Arnold, Roman Pohorsky, Gianluca Pappaccogli, Slimane Bekki, Elsa Dieudonné, Brice Barret, Brice Temime‐Roussel, Julia Schmale, Natalie Brett, Barbara D’Anna, Andrea Baccarini, Kathy S. Law, Meeta Cesler‐Maloney, Javier Fochesatto
article en
6 citations

Abstract

Abstract. Vertical in situ measurements of aerosols and trace gases were conducted in Fairbanks, Alaska, during winter 2022 as part of the Alaskan Layered Pollution and Chemical Analysis campaign (ALPACA). Using a tethered balloon, the study explores the dispersion of pollutants in the continental high-latitude stable boundary layer (SBL). Analysis of 24 flights revealed a stratified SBL structure with different pollution layers in the lowest tens of meters of the atmosphere, offering unprecedented detail. Surface emissions generally accumulated in a surface mixing layer (ML) extending to an average of 51 m, with a well-mixed sublayer (MsL) reaching 22 m. The height and concentrations within the ML were strongly influenced by a local wind driven by nearby topography under anticyclonic conditions. During strong radiative cooling, a drainage flow increased turbulence near the surface, altering the temperature profile and deepening the ML. Above the ML, pollution concentrations decreased but showed clear signs of freshly released anthropogenic emissions. Higher in the atmosphere, above elevated inversions, pollution levels were similar to previously reported Arctic haze concentrations, even though Fairbanks' outflow concentrations below elevated inversions were up to 6 times higher, likely due to power plant emissions. In situ measurements indicated that gas and particle tracer ratios in elevated power plant plumes differed significantly from those near the surface. Overall, pollution layers were strongly correlated with the temperature stratification and emission heights, emphasizing the need for improved representation of temperature inversions and emission sources in air quality models to enhance pollution forecasts.

Atmospheric chemistry and physicsVol. 25(6)
Centre National de la Recherche Scientifique (FR), University of Leeds (GB), Université Toulouse III - Paul Sabatier (FR), University of Alaska Fairbanks (US), Université Fédérale de Toulouse Midi-Pyrénées (FR), Université de Versailles Saint-Quentin-en-Yvelines (FR), Aix-Marseille Université (FR), Sorbonne Université (FR), Institute of Atmospheric Sciences and Climate (IT), Laboratoire de Physico-Chimie de l'Atmosphère (FR), Laboratoire atmosphères, milieux, observations spatiales (FR), National Research Council (IT), Université Paris 1 Panthéon-Sorbonne (FR), École Polytechnique Fédérale de Lausanne (CH)
National Science Foundation, Agence Nationale de la Recherche, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Institut Polaire Français Paul Emile Victor, Grand Équipement National De Calcul Intensif, Swiss Polar Institute, Natural Environment Research Council
Openalex Percentile: Top 2%
Atmospheric chemistry and aerosols
7.80
DOIOpen Access PDFOpenAlex
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