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Russo A, Sousa PM, Durão RM, Ramos AM, Salvador P, Linares C, Díaz J, Trigo RM. Saharan dust intrusions in the Iberian Peninsula: Predominant synoptic conditions. Sci Total Environ 2020; 717:137041. [PMID: 32065896 DOI: 10.1016/j.scitotenv.2020.137041] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/15/2020] [Accepted: 01/30/2020] [Indexed: 05/24/2023]
Abstract
The Iberian Peninsula (IP) is recurrently affected by dust transport from the Sahara Desert and from the semi-arid Sahel regions. African dust is one of the most important sources of particulate matter in the southern Mediterranean. Therefore, it is vital to understand the underlying processes that lead to episodes of air pollution associated to the occurrence of dust intrusions. This work proposes to make an extended characterization of the preferential circulation weather patterns associated to the onset of dust events affecting the IP between 2006 and 2016. Saharan dust intrusions were analysed and an automatic objective classification procedure was used to classify circulation weather patterns associated to dust events. The spatial distribution of intrusion episodes is not homogeneous throughout the IP, occurring less frequently at northern and northwestern locations than at central and southern sites. Moreover, days with Saharan dust intrusions were more frequent in summer months, and more probable to occur under regimes with a southerly component. Finally, two extreme events with high concentration of particulate matter were analysed relatively to their life-cycle and particle trajectories. The distinct extreme episodes can be associated to different synoptic situations. However, and despite different large-scale configurations, a south or south-easterly component over the region is responsible for the establishment of a dust transport from the Saharan region towards Iberia, and thus leading to the intrusion onset. These results were supported by the calculation of back-trajectories which allowed to source apportioning the particles' origin, through a clear trajectory of air parcels originating from northern Africa in both events. The proposed framework can be useful to the prediction of dust and air pollution events based on the forecast of circulation weather patterns, as the results show that these events across the IP are mainly induced by specific patterns.
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Affiliation(s)
- A Russo
- Instituto Dom Luíz, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edifício C8, Piso 3, 1749-016 Lisboa, Portugal.
| | - P M Sousa
- Instituto Dom Luíz, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edifício C8, Piso 3, 1749-016 Lisboa, Portugal
| | - R M Durão
- IPMA-Instituto Português do Mar e Atmosfera, Lisboa, Portugal; Centro de Recursos Naturais e Ambiente, Departamento de Engenharia Civil, Arquitectura e Georrecursos, Instituto Superior Técnico, Universidade de Lisboa, Portugal
| | - A M Ramos
- Instituto Dom Luíz, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edifício C8, Piso 3, 1749-016 Lisboa, Portugal
| | - P Salvador
- Environmental Department of the Research Center for Energy, Environment and Technology (CIEMAT), Madrid, Spain
| | - C Linares
- Department of Epidemiology and Biostatistic, National School of Public Health, Carlos III National Institute of Health, Madrid, Spain
| | - J Díaz
- Department of Epidemiology and Biostatistic, National School of Public Health, Carlos III National Institute of Health, Madrid, Spain
| | - R M Trigo
- Instituto Dom Luíz, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Edifício C8, Piso 3, 1749-016 Lisboa, Portugal; Departamento de Meteorologia, Universidade Federal do Rio de Janeiro, 21941-916, Rio de Janeiro, Brazil
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Oduber F, Calvo AI, Blanco-Alegre C, Castro A, Nunes T, Alves C, Sorribas M, Fernández-González D, Vega-Maray AM, Valencia-Barrera RM, Lucarelli F, Nava S, Calzolai G, Alonso-Blanco E, Fraile B, Fialho P, Coz E, Prevot ASH, Pont V, Fraile R. Unusual winter Saharan dust intrusions at Northwest Spain: Air quality, radiative and health impacts. Sci Total Environ 2019; 669:213-228. [PMID: 30878930 DOI: 10.1016/j.scitotenv.2019.02.305] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 02/16/2019] [Accepted: 02/19/2019] [Indexed: 05/14/2023]
Abstract
Saharan air masses can transport high amounts of mineral dust particles and biological material to the Iberian Peninsula. During winter, this kind of events is not very frequent and usually does not reach the northwest of the Peninsula. However, between 21 and 22 February 2016 and between 22 and 23 February 2017, two exceptional events were registered in León (Spain), which severely affected air quality. An integrative approach including: i) typical synoptic conditions; ii) aerosol chemical composition; iii) particle size distributions; iv) pollen concentration; v) aerosol optical depth (AOD); vi) radiative forcing and vii) estimation of the impact of aerosols in the respiratory tract, was carried out. In the global characterization of these events, the exceedance of the PM10 daily limit value, an increase in the coarse mode and a rise in the iron concentration were observed. On the 2016 event, an AOD and extinction-related Ångström exponent clearly characteristic of desert aerosol (1.1 and 0.05, respectively) were registered. Furthermore, pollen grains not typical of flowering plants in this period were identified. The chemical analysis of the aerosol from the 2017 event allowed us to confirm the presence of the main elements associated with mineral sources (aluminum, calcium, and silica concentrations). An increase in the SO42-, NO3- and Cl- concentrations during the Saharan dust intrusion was also noted. However, in this event, there was no presence of atypical pollen types. The estimated dust radiative forcing traduced a cooling effect for surface and atmosphere during both events, corroborated by trends of radiative flux measurements. The estimated impact on the respiratory tract regions of the high levels of particulate matter during both Saharan dust intrusions showed high levels for the respirable fraction.
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Affiliation(s)
- F Oduber
- Department of Physics, IMARENAB University of León, León, Spain
| | - A I Calvo
- Department of Physics, IMARENAB University of León, León, Spain
| | - C Blanco-Alegre
- Department of Physics, IMARENAB University of León, León, Spain
| | - A Castro
- Department of Physics, IMARENAB University of León, León, Spain
| | - T Nunes
- Centre for Environmental and Marine Studies, Department of Environment, University of Aveiro, Aveiro, Portugal
| | - C Alves
- Centre for Environmental and Marine Studies, Department of Environment, University of Aveiro, Aveiro, Portugal
| | - M Sorribas
- El Arenosillo-Atmospheric Sounding Station, Atmospheric Research and Instrumentation Branch, INTA, Mazagón, Huelva, Spain
| | - D Fernández-González
- Biodiversity and Environmental Management, University of León, Spain; Institute of Atmospheric Sciences and Climate-CNR, Bologna, Italy
| | - A M Vega-Maray
- Biodiversity and Environmental Management, University of León, Spain
| | | | - F Lucarelli
- Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Italy
| | - S Nava
- Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Italy
| | - G Calzolai
- Department of Physics and Astronomy, University of Florence and I.N.F.N., Florence, Italy
| | - E Alonso-Blanco
- Centre for Energy, Environment and Technology Research (CIEMAT), Department of the Environment, Madrid, Spain
| | - B Fraile
- Department of Biomedicine and Biotechnology, University of Alcalá, Alcalá de Henares, Spain
| | - P Fialho
- Research Institute for Volcanology and Risk Assessment-IVAR, Ponta Delgada, Portugal
| | - E Coz
- Centre for Energy, Environment and Technology Research (CIEMAT), Department of the Environment, Madrid, Spain
| | - A S H Prevot
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - V Pont
- Laboratory of Aerology, National Center for Scientific Research (CNRS), University of Toulouse, Toulouse, France
| | - R Fraile
- Department of Physics, IMARENAB University of León, León, Spain.
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