New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula

<p>A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size dist...

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Main Authors: J. A. Casquero-Vera, H. Lyamani, L. Dada, S. Hakala, P. Paasonen, R. Román, R. Fraile, T. Petäjä, F. J. Olmo-Reyes, L. Alados-Arboledas
Format: Article
Language:English
Published: Copernicus Publications 2020-11-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/20/14253/2020/acp-20-14253-2020.pdf
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author J. A. Casquero-Vera
J. A. Casquero-Vera
H. Lyamani
H. Lyamani
L. Dada
S. Hakala
P. Paasonen
R. Román
R. Fraile
T. Petäjä
F. J. Olmo-Reyes
F. J. Olmo-Reyes
L. Alados-Arboledas
L. Alados-Arboledas
author_facet J. A. Casquero-Vera
J. A. Casquero-Vera
H. Lyamani
H. Lyamani
L. Dada
S. Hakala
P. Paasonen
R. Román
R. Fraile
T. Petäjä
F. J. Olmo-Reyes
F. J. Olmo-Reyes
L. Alados-Arboledas
L. Alados-Arboledas
author_sort J. A. Casquero-Vera
collection DOAJ
description <p>A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size distributions at two stations located close to each other (<span class="inline-formula">∼</span>&thinsp;20&thinsp;km) but at different altitudes: urban (UGR; 680&thinsp;m&thinsp;a.s.l., metres above sea level) and high-altitude remote (SNS; 2500&thinsp;m&thinsp;a.s.l.) sites, both in the area of Granada, Spain, and part of AGORA observatory (Andalusian Global ObseRvatory of the Atmosphere). The analysis shows a significant contribution of nucleation mode aerosol particles to the total aerosol number concentration at both sites, with a contribution of 47&thinsp;% and 48&thinsp;% at SNS and UGR, respectively. Due to the important contribution of NPF events to the total aerosol number concentrations and their high occurrence frequency (<span class="inline-formula">&gt;</span>&thinsp;70&thinsp;%) during the study period, a detailed analysis of NPF events is done in order to get insight into the possible mechanisms and processes involved in NPF events at these contrastive sites. At SNS, NPF is found to be associated with the transport of gaseous precursors from lower altitudes by orographic buoyant upward flows. NPF events at the SNS site are always observed from the smallest measured sizes of the aerosol size distribution (4&thinsp;nm), implying that NPF takes place in or in the vicinity of the high-altitude SNS station rather than being transported from lower altitudes. Although NPF events at the mountain site seem to be connected with those occurring at the urban site, growth rates (GRs) at SNS are higher than those at the UGR site (GR<span class="inline-formula"><sub>7−25</sub></span> of 6.9 and 4.5&thinsp;nm&thinsp;h<span class="inline-formula"><sup>−1</sup></span> and GR<span class="inline-formula"><sub>4−7</sub></span> of 4.1 and 3.6&thinsp;nm&thinsp;h<span class="inline-formula"><sup>−1</sup></span> at SNS and UGR, respectively). This fact could have special importance for the production of cloud condensation nuclei (CCN) and therefore for cloud formations which may affect regional/global climate, since larger GRs at mountain sites could translate to a larger survival probability of NPF particles reaching CCN sizes, due to the shorter time period needed for the growth. The analysis of sulfuric acid (H<span class="inline-formula"><sub>2</sub></span>SO<span class="inline-formula"><sub>4</sub></span>) shows that the contribution of H<span class="inline-formula"><sub>2</sub></span>SO<span class="inline-formula"><sub>4</sub></span> is able to explain a minimal fraction contribution to the observed GRs at both sites (<span class="inline-formula">&lt;</span>&thinsp;1&thinsp;% and <span class="inline-formula">&lt;</span>&thinsp;10&thinsp;% for the 7–25 and 4–7&thinsp;nm size ranges, respectively), indicating that other condensing vapours are responsible for the majority of particle growth, as well as the differing growth rates between the two sites. Results also show that the condensation sink (CS) does not play a relevant role in NPF processes at both sites and points to the availability of volatile organic compounds (VOCs) as one of the main factors controlling the NPF events at both sites. Finally, a closer analysis of the NPF events that were observed at the SNS site during a Saharan dust episode that occurred during the field campaign was carried out, evidencing the role of TiO<span class="inline-formula"><sub>2</sub></span> and F<span class="inline-formula"><sub>2</sub></span>O<span class="inline-formula"><sub>3</sub></span> together with VOCs in promoting new particle formation during this dust intrusion event. Although<span id="page14254"/> further investigation is needed to improve our understanding in this topic, this result suggests that climate effects of mineral dust and NPF are not disconnected from each other as it was commonly thought. Therefore, since mineral dust contributes to a major fraction of the global aerosol mass load, dust–NPF interaction should be taken into account in global aerosol-climate modelling for better climate change prediction.</p>
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spelling doaj.art-764dce94cdd04b5db8068b2f728a26d82022-12-22T00:57:57ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-11-0120142531427110.5194/acp-20-14253-2020New particle formation at urban and high-altitude remote sites in the south-eastern Iberian PeninsulaJ. A. Casquero-Vera0J. A. Casquero-Vera1H. Lyamani2H. Lyamani3L. Dada4S. Hakala5P. Paasonen6R. Román7R. Fraile8T. Petäjä9F. J. Olmo-Reyes10F. J. Olmo-Reyes11L. Alados-Arboledas12L. Alados-Arboledas13Andalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Autonomous Government of Andalusia, Granada, SpainDepartment of Applied Physics, University of Granada, Granada, SpainAndalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Autonomous Government of Andalusia, Granada, SpainDepartment of Applied Physics, University of Granada, Granada, SpainInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandGrupo de Óptica Atmosférica (GOA), Universidad de Valladolid, Valladolid, SpainDepartment of Physics, University of Leon, Leon, SpainInstitute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, FinlandAndalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Autonomous Government of Andalusia, Granada, SpainDepartment of Applied Physics, University of Granada, Granada, SpainAndalusian Institute for Earth System Research (IISTA-CEAMA), University of Granada, Autonomous Government of Andalusia, Granada, SpainDepartment of Applied Physics, University of Granada, Granada, Spain<p>A substantial fraction of the atmospheric aerosols originates from secondary new particle formation (NPF), where atmospheric vapours are transformed into particles that subsequently grow to larger sizes, affecting human health and the climate. In this study, we investigate aerosol size distributions at two stations located close to each other (<span class="inline-formula">∼</span>&thinsp;20&thinsp;km) but at different altitudes: urban (UGR; 680&thinsp;m&thinsp;a.s.l., metres above sea level) and high-altitude remote (SNS; 2500&thinsp;m&thinsp;a.s.l.) sites, both in the area of Granada, Spain, and part of AGORA observatory (Andalusian Global ObseRvatory of the Atmosphere). The analysis shows a significant contribution of nucleation mode aerosol particles to the total aerosol number concentration at both sites, with a contribution of 47&thinsp;% and 48&thinsp;% at SNS and UGR, respectively. Due to the important contribution of NPF events to the total aerosol number concentrations and their high occurrence frequency (<span class="inline-formula">&gt;</span>&thinsp;70&thinsp;%) during the study period, a detailed analysis of NPF events is done in order to get insight into the possible mechanisms and processes involved in NPF events at these contrastive sites. At SNS, NPF is found to be associated with the transport of gaseous precursors from lower altitudes by orographic buoyant upward flows. NPF events at the SNS site are always observed from the smallest measured sizes of the aerosol size distribution (4&thinsp;nm), implying that NPF takes place in or in the vicinity of the high-altitude SNS station rather than being transported from lower altitudes. Although NPF events at the mountain site seem to be connected with those occurring at the urban site, growth rates (GRs) at SNS are higher than those at the UGR site (GR<span class="inline-formula"><sub>7−25</sub></span> of 6.9 and 4.5&thinsp;nm&thinsp;h<span class="inline-formula"><sup>−1</sup></span> and GR<span class="inline-formula"><sub>4−7</sub></span> of 4.1 and 3.6&thinsp;nm&thinsp;h<span class="inline-formula"><sup>−1</sup></span> at SNS and UGR, respectively). This fact could have special importance for the production of cloud condensation nuclei (CCN) and therefore for cloud formations which may affect regional/global climate, since larger GRs at mountain sites could translate to a larger survival probability of NPF particles reaching CCN sizes, due to the shorter time period needed for the growth. The analysis of sulfuric acid (H<span class="inline-formula"><sub>2</sub></span>SO<span class="inline-formula"><sub>4</sub></span>) shows that the contribution of H<span class="inline-formula"><sub>2</sub></span>SO<span class="inline-formula"><sub>4</sub></span> is able to explain a minimal fraction contribution to the observed GRs at both sites (<span class="inline-formula">&lt;</span>&thinsp;1&thinsp;% and <span class="inline-formula">&lt;</span>&thinsp;10&thinsp;% for the 7–25 and 4–7&thinsp;nm size ranges, respectively), indicating that other condensing vapours are responsible for the majority of particle growth, as well as the differing growth rates between the two sites. Results also show that the condensation sink (CS) does not play a relevant role in NPF processes at both sites and points to the availability of volatile organic compounds (VOCs) as one of the main factors controlling the NPF events at both sites. Finally, a closer analysis of the NPF events that were observed at the SNS site during a Saharan dust episode that occurred during the field campaign was carried out, evidencing the role of TiO<span class="inline-formula"><sub>2</sub></span> and F<span class="inline-formula"><sub>2</sub></span>O<span class="inline-formula"><sub>3</sub></span> together with VOCs in promoting new particle formation during this dust intrusion event. Although<span id="page14254"/> further investigation is needed to improve our understanding in this topic, this result suggests that climate effects of mineral dust and NPF are not disconnected from each other as it was commonly thought. Therefore, since mineral dust contributes to a major fraction of the global aerosol mass load, dust–NPF interaction should be taken into account in global aerosol-climate modelling for better climate change prediction.</p>https://acp.copernicus.org/articles/20/14253/2020/acp-20-14253-2020.pdf
spellingShingle J. A. Casquero-Vera
J. A. Casquero-Vera
H. Lyamani
H. Lyamani
L. Dada
S. Hakala
P. Paasonen
R. Román
R. Fraile
T. Petäjä
F. J. Olmo-Reyes
F. J. Olmo-Reyes
L. Alados-Arboledas
L. Alados-Arboledas
New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
Atmospheric Chemistry and Physics
title New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
title_full New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
title_fullStr New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
title_full_unstemmed New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
title_short New particle formation at urban and high-altitude remote sites in the south-eastern Iberian Peninsula
title_sort new particle formation at urban and high altitude remote sites in the south eastern iberian peninsula
url https://acp.copernicus.org/articles/20/14253/2020/acp-20-14253-2020.pdf
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