Influencia de la microestructura de la precipitación en las características del aerosol atmosférico = Influence of precipitation microstructure on the characteristics of atmospheric aerosol

352 p.La presente tesis se centra en el estudio del proceso por el que los aerosoles son barridos (scavenging) por hidrometeoros en la atmósfera, depositándolos sobre la superficie terrestre. Existen dos tipos de scavenging en función de dónde ocurre el proceso: dentro de la nube o ICS (In-Cloud Scavenging) o bien debajo de la nube o BCS (Below-Cloud Scavenging), a través de los procesos de precipitación, que pueden tomar diversas formas: lluvia, tormenta, granizo, nieve, etc

Laboratorios virtuales aplicados a la Física universitaria: situación actual y perspectivas futuras

El presente trabajo trata del estado actual de las herramientas aplicables a las prácticas de laboratorio en las asignaturas universitarias de Física. La situación causada por la pandemia provocada por el coronavirus SARS-CoV-2 ha provocado la proliferación de empresas que desarrollan laboratorios virtuales y el desarrollo de múltiples herramientas, gratuitas o no, aplicables a las prácticas online. Este trabajo recoge una descripción de las principales herramientas disponibles. Además, se comparan los resultados de una misma práctica realizada de modo online y presencial sobre la ley de Stokes. Se ha observado que ambos modos presentaron similares resultados académicos, con un menor tiempo de práctica y un menor coste asociado para la práctica online. Por último, se incluye una reflexión sobre la futura aplicación de prácticas virtuales 3D y su utilización conjunta con prácticas presenciales

Virtual laboratories applied to university Physics: current situation and future scenarios

[ES] El presente trabajo trata del estado actual de las herramientas aplicables a las prácticas de laboratorio en las asignaturas universitarias de Física. La situación causada por la pandemia provocada por el coronavirus SARS-CoV-2 ha provocado la proliferación de empresas que desarrollan laboratorios virtuales y el desarrollo de múltiples herramientas, gratuitas o no, aplicables a las prácticas online. Este trabajo recoge una descripción de las principales herramientas disponibles. Además, se comparan los resultados de una misma práctica realizada de modo online y presencial sobre la ley de Stokes. Se ha observado que ambos modos presentaron similares resultados académicos, con un menor tiempo de práctica y un menor coste asociado para la práctica online. Por último, se incluye una reflexión sobre la futura aplicación de prácticas virtuales 3D y su utilización conjunta con prácticas presenciales[EN] This work deals with the current state of the art of tools applicable to the laboratory practices in the university subjects of Physics. The situation caused by the SARS-CoV-2 coronavirus has triggered the number of companies that develop virtual laboratories and the development of multiple tools, free or not, applicable to online practices. A description of the main tools available in included. In addition, the results of the same practice carried out online and on-site on Stokes's law are compared. It has been observed that both modes presented similar academic results, with a shorter duration and a lower associated cost for online practice. Finally, a reflection on the future application of 3D virtual practices and their joint use with on-site practices is include

Connection between weather types and air pollution levels: a 19-year study in nine EMEP stations in Spain

This article belongs to the Special Issue 2nd Edition of Integrated Human Exposure to Air Pollution[EN] This study focuses on the analysis of the distribution, both spatial and temporal, of the PM10 (particulate matter with a diameter of 10 µm or less) concentrations recorded in nine EMEP (European Monitoring and Evaluation Programme) background stations distributed throughout mainland Spain between 2001 and 2019. A study of hierarchical clusters was used to classify the stations into three main groups with similarities in yearly concentrations: GC (coastal location), GNC (north–central location), and GSE (southeastern location). The highest PM10 concentrations were registered in summer. Annual evolution showed statistically significant decreasing trends in PM10 concentration in all the stations covering a range from −0.21 to −0.50 µg m−3/year for Barcarrota and Víznar, respectively. Through the Lamb classification, the weather types were defined during the study period, and those associated with high levels of pollution were identified. Finally, the values exceeding the limits established by the legislation were analyzed for every station assessed in the studySIThis work was partially supported by the Junta de Castilla y Leon (Grant LE025P20) and by the AEROHEALTH and C3HEALTH projects (Ministry of Science and Innovation, Grants PID2019-106164RBI00 and TED2021-132292B-I00). The study was also cofinanced with FEDER fund

Effect of prevailing winds and land use on Alternaria airborne spore load

[EN] Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens. Several aerobiological studies showing a strong relationship between concentrations of airborne spore and meteorological parameters have consequently been developed. However, the Alternaria airborne load variation has not been thoroughly investigated because it is difficult to assess their sources, as they are a very common and widely established phytopathogen. The objective of this study is to estimate the impact of vegetation and land uses as potential sources on airborne spore load and to know their influence, particularly, in cases of long-medium distance transport. The daily airborne spore concentration was studied over a 5-year period in Le´on and Valladolid, two localities of Castilla y Le´on (Spain), with differences in their bioclimatic and land use aspects. Moreover, the land use analysis carried out within a 30 km radius of each monitoring station was combined with air mass data in order to search for potential emission sources. The results showed a great spatial variation between the two areas, which are relatively close to each other. The fact that the spore concentrations recorded in Valladolid were higher than those in Le´on was owing to prevailing winds originating from large areas covered by cereal crops, especially during the harvest period. However, the prevailing winds in Le´on came from areas dominated by forest and shrubland, which explains the low airborne spore load, since the main Alternaria sources were the grasslands located next to the trap. Furthermore, the risk days in this location presented an unusual wind direction. This study reveals the importance of land cover and wind speed and direction data for establishing potential airborne routes of spore transport in order to improve the Alternaria forecasting models. The importance of conducting Alternaria aerobiological studies at a local level is also highlighted.SIThe authors are grateful to the Castilla y Le´on Government’s Health Department for funding the RACYL. This study was partially supported by the AEROHEALTH project [Spanish Ministry of Science and Innovation, Grant PID 2019-106164RB-I00, co-financed with European FEDER funds] and the Junta de Castilla y Le´on, co-financed with European FEDER funds [Grant LE025P20]. A. Rodríguez-Fern´andez acknowledges the Orden EDU/601/2020 grant from the Junta de Castilla y Le´on, co-financed with European FEDER fund

Rainfall characteristics in León in 2016 and 2017

Ejemplar dedicado a: XXXV Jornadas Científicas de la AME: Predicción de tiempo y clima orientada a impactos - 19º Encuentro hispano-luso de Meteorología. Sesión de presentaciones en póster[EN] Nowadays, air pollution is one of the principal risk to human health and rain is the main sink of aerosol particles in the atmosphere, since it is the main process to mitigate pollution. Furthermore, the study of rainfall characteristics is crucial because it can provide information about present and future risks in an area, related to rain amount or intensity. In order to know the characteristics of the precipitation in the city of León, rain was sampled during 2016 and 2017 using a Laser Precipitation Monitor (LPM) of Thies Clima which registered drops between 0.125 and 8 mm in 22 channels. Furthermore, a Circulation Weather Types (CWTs) classification was carried out based on Lamb (1972), to identify the weather type related to a peculiar synoptic situation in days with rain. Focusing on rain characteristics in the city of León, 3.23·109 drops m-2 have fallen in 2016 with a mean size of 0.36±0.20 mm and 1.06·109 drops m-2 in 2017 with a mean size of 0.35±0.19 mm. The rain characteristic according to Lamb Weather Types during rain events will be analyzedSIThis work was partially supported by the Spanish Ministry of Economy and Com-petitiveness (Grant TEC2014-57821-R), the University of León (Programa Propio 2015/00054/001) and the AERORAIN project (Ministry of Economy and Competitive-ness, Grant CGL2014-52556-R, ERDF co-financed). F. Oduber acknowledges the grant BES-2015-074473 from the Ministry of Economy and Competitiveness. C. del Blanco Alegre acknowledges the grant FPU16/05764 from the Ministry of Education, Culture and Sport

Influence of meteorological parameters on air pollutant concentrations in León, Spain

Ejemplar dedicado a: XXXV Jornadas Científicas de la AME: Predicción de tiempo y clima orientada a impactos - 19º Encuentro hispano-luso de Meteorología. Sesión de presentaciones en póster[EN] The presence of pollutants in the atmosphere may cause a negative impact on human health and the environment. The main air pollutants are carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), ozone (O3) and particulate matter (PM). The correlation between the air pollutant concentrations and the weather variables provides valuable information about the emission sources and leads to a better understanding of the processes responsible for the spatial and temporal distribution of air pollutants. This enables policy makers to establish mitigation measures. The present study was carried out in León city, located in the northwest of the Iberian Peninsula (42° 36’ N, 05º 35’ W and 838 m above sea level). For this study, the data available in the Air Quality Network of Junta of Castilla y León (www.servicios.jcyl.es/esco) for the period between 1 January and 31 December 2016 were used. Two air quality stations were operating during the studied period (Fig.1): i) an urban traffic station located in San Ignacio de Loyola Avenue (Station 1, 05° 35’14”W 42° 36’14”N) and ii) a background station located in the Coto Escolar (Station 4, 05° 33’59”W 42° 34’31”N)SIThis work was partially supported by the Spanish Ministry of Economy and Competitiveness (Grant TEC2014-57821-R), the University of León (Programa Propio 2015/00054/001) and AERORAIN project (Ministry of Economy and Competitiveness, Grant CGL2014-52556-R, ERDF co-financed). F. Oduber acknowledges the grant BES- 2015-074473 from the Spanish Ministry of Economy and Competitiveness. C. Blanco- Alegre acknowledges the grant FPU16-05764 from the Spanish Ministry of Education, Culture and Spor

The role of snow in scavenging aerosol particles: A physical-chemical characterization

[EN] The below cloud scavenging of aerosols by snow has been analysed in León (NW Spain). Six snow events were registered over the course of one year of study. Ultrafine and accumulation aerosol particles were measured using a scanning mobility particle sizer spectrometer, while hydrometeors were characterized using a disdrometer. Furthermore, the chemical composition of the melted snow-water samples (soluble and insoluble fractions) was analysed. The scavenging coefficient (λ) showed a great variability among events. An effective washing of particles was observed during the first 30 min of snowfall. The mean change in the scavenging efficiency (%ΔC) of particle number concentration (PNC) and λ coefficient during this time interval were: i) nucleation mode: 36.3 % and 3.02 · 10−4 s−1; ii) Aitken mode: 30.4 % and 2.37 · 10−4 s−1 and iii) accumulation mode: 22.4 % and 1.77 · 10−4 s−1. The range of particle sizes that is less efficiently scavenged by snowfall was observed between 400 and 600 nm. When analyzing the whole snow event, an increase of PNC was observed. Two possible explanations underlie this behaviour: it could be caused by changes in air masses or by the resuspension of aerosol particles scavenged by snowflakes upon reaching the ground. A clear relationship was observed between Ca2+, SO42− and NO3− concentrations of aerosol particles before the snow event and the concentrations registered in the melted snow-water. The largest and smallest changes in aerosol number concentrations were caused by snowflakes of 3 and 6 mm in diameter, respectively. The particle size distributions (PSD) were fitted to log-normal distributions and the parameters were compared before and after snowfall.S

Quantification of source specific black carbon scavenging using an aethalometer and a disdrometer

[EN] Aerosol black carbon (BC) is the second strongest contributor to global warming, after CO2, and it is linked to many adverse health effects. A sampling campaign of 15 months was carried out in León (Spain) in order to evaluate the scavenging of BC with an ensemble aethalometer-disdrometer. The aethalometer provides the concentration of equivalent black carbon (eBC), and the disdrometer, the raindrop size distribution. A total of seventy-five rain events were studied and in 73% of them there was an effective (eBCinitial > eBCfinal) scavenging, with a mean decrease of 48 ± 37% in long rain events (>8 h) and 39 ± 38% in short rain events. The scavenging of BC is strongly related to its source. Thus, the scavenging coefficient (SC) mean value of the BC from fossil fuel (eBCff) for short and long rain events was 5.1 10−5 and 1.3 10−5 s−1, respectively. For the BC from biomass burning (eBCbb), the SC values were 1.6 10−4 and 2.8 10−5 s−1 in short and long events, respectively. There was a significant positive correlation between the SC and the number of drops with diameters between 0.375 and 2.5 mm. Rain scavenging of eBC was analyzed depending on the air mass origin obtaining an effective scavenging for air masses from Atlantic, Arctic and Africa. A linear model (R2 = 0.72) was built to estimate the ΔeBC values with variables from an aethalometer, a disdrometer and a weather station: eBC concentration before rain, swept volume and precipitation accumulated. A Kolmogorov-Smirnov statistical test confirmed the goodness of fit of the model to the measured dataSIThis work was partially supported by the Spanish Ministry of Economy and Competitiveness (Grant TEC2014-57821-R), the University of León (Programa Propio 2015/00054/001) and the AERORAIN project (Ministry of Economy and Competitiveness, Grant CGL2014-52556-R, co-financed with FEDER funds). F. Oduber acknowledges the grant BES-2015-074473 from the Ministry of Economy and Competitiveness. C. del Blanco Alegre acknowledges the grant FPU16/05764 from the Ministry of Education, Culture and Sport

Identifying key environmental factors to model Alt a 1 airborne allergen presence and variation

[EN] Fungal spores, commonly found in the atmosphere, can trigger important respiratory disorders. The glycoprotein Alt a 1 is the major allergen present in conidia of the genus Alternaria and has a high clinical relevance for people sensitized to fungi. Exposure to this allergen has been traditionally assessed by aerobiological spore counts, although this does not always offer an accurate estimate of airborne allergen load. This study aims to pinpoint the key factors that explain the presence and variation of Alt a 1 concentration in the atmosphere in order to establish exposure risk periods and improve forecasting models. Alternaria spores were sampled using a Hirst-type volumetric sampler over a five-year period. The allergenic fraction from the bioaerosol was collected using a low-volume cyclone sampler and Alt a 1 quantified by Enzyme-Linked ImmunoSorbent Assay. A cluster analysis was executed in order to group days with similar environmental features and then analyze days with the presence of the allergen in each of them. Subsequently, a quadratic discriminant analysis was performed to evaluate if the selected variables can predict days with high Alt a 1 load. The results indicate that higher temperatures and absolute humidity favor the presence of Alt a 1 in the atmosphere, while time of precipitation is related to days without allergen. Moreover, using the selected parameters, the quadratic discriminant analysis to predict days with allergen showed an accuracy rate between 67 % and 85 %. The mismatch between daily airborne concentration of Alternaria spores and allergen load can be explained by the greater contribution of medium-to-long distance transport of the allergen from the major emission sources as compared with spores. Results highlight the importance of conducting aeroallergen quantification studies together with spore counts to improve the forecasting models of allergy risk, especially for fungal spores.S