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Significant differences in black and brown carbon concentrations at urban and suburban sites

Light-absorbing carbonaceous particles (LAC) may cause and/or exacerbate non-communicable diseases, interfere with the Earth's radiative balance, darken urban buildings and impair vistas. In this study, we explored the temporal behaviour of LAC concentrations measured at wavelengths of 370 nm (...

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Autores principales: Targino, Admir Créso, Moreno, Fabian Leonardo, Krecl, Patricia, Cardoso, João Vitor
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Elsevier 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10374922/
https://www.ncbi.nlm.nih.gov/pubmed/37520949
http://dx.doi.org/10.1016/j.heliyon.2023.e18418
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author Targino, Admir Créso
Moreno, Fabian Leonardo
Krecl, Patricia
Cardoso, João Vitor
author_facet Targino, Admir Créso
Moreno, Fabian Leonardo
Krecl, Patricia
Cardoso, João Vitor
author_sort Targino, Admir Créso
collection PubMed
description Light-absorbing carbonaceous particles (LAC) may cause and/or exacerbate non-communicable diseases, interfere with the Earth's radiative balance, darken urban buildings and impair vistas. In this study, we explored the temporal behaviour of LAC concentrations measured at wavelengths of 370 nm (brown carbon, BrC) and 880 nm (black carbon, BC) at two sites of a mid-sized city in Brazil. We observed sharp changes in LAC concentrations at the city centre site in response to variations in traffic volume. The highest concentrations were observed when winds originated from both the city core and from the direction of the bus terminal. The suburban site exhibited a notably uniform diurnal pattern and consistently lower LAC concentrations throughout the day. Nevertheless, substantial increases during the evening led to mean BrC and BC concentrations (2.6 and 2.2 μg m(−3), respectively) comparable to daytime peaks observed in the city centre (3 μg m(−3) and 2.5 μg m(−3)). This phenomenon was attributed to the burning of residential waste and overgrown vegetation in nearby vacant lots. Moreover, the highest concentrations coincided with periods of low wind speeds, usually linked to non-buoyant plumes from point sources. BrC concentrations surpassed BC concentrations, even at the city centre site. Not only was the Ångström absorption exponent (Å(370/880)) larger at the suburban site compared to the city centre (95th percentiles of 1.73 and 1.38, respectively), but it also exhibited a wider span. Overall, the combined LAC and Å(370/880) data indicated that i) biomass burning is a major source of LAC at the suburban site; ii) at the city centre, bare BC particles may become internally mixed with BrC from biomass or fossil fuel emissions and enhance absorption at lower wavelengths. The occurrence of LAC peaks outside the evening rush hours suggests that other sources but on-road vehicular emissions may contribute to the deterioration of the air quality in the urban core. Tackling air quality across the urban perimeter requires targeting other potential sources but traffic emissions.
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spelling pubmed-103749222023-07-29 Significant differences in black and brown carbon concentrations at urban and suburban sites Targino, Admir Créso Moreno, Fabian Leonardo Krecl, Patricia Cardoso, João Vitor Heliyon Research Article Light-absorbing carbonaceous particles (LAC) may cause and/or exacerbate non-communicable diseases, interfere with the Earth's radiative balance, darken urban buildings and impair vistas. In this study, we explored the temporal behaviour of LAC concentrations measured at wavelengths of 370 nm (brown carbon, BrC) and 880 nm (black carbon, BC) at two sites of a mid-sized city in Brazil. We observed sharp changes in LAC concentrations at the city centre site in response to variations in traffic volume. The highest concentrations were observed when winds originated from both the city core and from the direction of the bus terminal. The suburban site exhibited a notably uniform diurnal pattern and consistently lower LAC concentrations throughout the day. Nevertheless, substantial increases during the evening led to mean BrC and BC concentrations (2.6 and 2.2 μg m(−3), respectively) comparable to daytime peaks observed in the city centre (3 μg m(−3) and 2.5 μg m(−3)). This phenomenon was attributed to the burning of residential waste and overgrown vegetation in nearby vacant lots. Moreover, the highest concentrations coincided with periods of low wind speeds, usually linked to non-buoyant plumes from point sources. BrC concentrations surpassed BC concentrations, even at the city centre site. Not only was the Ångström absorption exponent (Å(370/880)) larger at the suburban site compared to the city centre (95th percentiles of 1.73 and 1.38, respectively), but it also exhibited a wider span. Overall, the combined LAC and Å(370/880) data indicated that i) biomass burning is a major source of LAC at the suburban site; ii) at the city centre, bare BC particles may become internally mixed with BrC from biomass or fossil fuel emissions and enhance absorption at lower wavelengths. The occurrence of LAC peaks outside the evening rush hours suggests that other sources but on-road vehicular emissions may contribute to the deterioration of the air quality in the urban core. Tackling air quality across the urban perimeter requires targeting other potential sources but traffic emissions. Elsevier 2023-07-18 /pmc/articles/PMC10374922/ /pubmed/37520949 http://dx.doi.org/10.1016/j.heliyon.2023.e18418 Text en © 2023 The Authors https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Research Article
Targino, Admir Créso
Moreno, Fabian Leonardo
Krecl, Patricia
Cardoso, João Vitor
Significant differences in black and brown carbon concentrations at urban and suburban sites
title Significant differences in black and brown carbon concentrations at urban and suburban sites
title_full Significant differences in black and brown carbon concentrations at urban and suburban sites
title_fullStr Significant differences in black and brown carbon concentrations at urban and suburban sites
title_full_unstemmed Significant differences in black and brown carbon concentrations at urban and suburban sites
title_short Significant differences in black and brown carbon concentrations at urban and suburban sites
title_sort significant differences in black and brown carbon concentrations at urban and suburban sites
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10374922/
https://www.ncbi.nlm.nih.gov/pubmed/37520949
http://dx.doi.org/10.1016/j.heliyon.2023.e18418
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