Elisa Gordo

Spatial and temporal variation of the impact of an extreme Saharan dust event

[1]xa0The impact on PM10, meteorology and visibility of the severe Saharan dust outbreak registered in Europe in October 2008 is evaluated in detail in mainland Spain and the Balearic Islands. Data from a large number of air quality stations (261), METAR observations at 39 airports, besides records from meteorological networks, were used. Information from dispersion models, satellite observations, synoptic charts and back-trajectory analysis, supported the interpretation. During the event, 89% of the monitoring stations exceeded the daily limit value. The highest daily averaged PM10 concentration across Spain ranged from 378 to 18μg m−3, following a hyperbolic decay with increasing latitude. An opposite relationship between visibility and PM10 was found for data at 12 UTC. The strength of the episode may be related to strong subsidence at low levels over the Iberian Peninsula.

Study of 7Be and 210Pb as radiotracers of African intrusions in Malaga (Spain)

The relationship between the particulate matter in the atmosphere of Malaga and the origin of air masses with special attention to African intrusions was analyzed. The concentrations of PM10 and the activities of some radionuclides ((7)Be and (210)Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. (210)Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of (7)Be is very low in the vicinity of the Earths surface, and increases with altitude, making it a great tracer of stratospheric air masses in the troposphere. Studies of radionuclide activities in aerosol particles provide a means for evaluating the integrated effects of transport and meteorology on the atmospheric loadings of substances with different sources. Measurements of aerosol mass concentration and specific activities of (7)Be and (210)Pb in aerosols at Malaga (36° 43 40″ N; 4° 28 8″ W) for the period 2009-2011 were used to obtain the relationships between radionuclide activities and airflow patterns by comparing the data grouped by air mass trajectory. The average concentration values of (7)Be and (210)Pb over the 3-year period have been found to be 5.05 and 0.55 mBq m(-3), respectively, with mean aerosol mass concentration of 53.6 μg m(-3). Taking into account the outbreaks of the daily values limits of PM10 in the study period (2009-2011), the origin of air masses is studied to explain three different situations of both radionuclides (7)Be and (210)Pb: 1) high concentrations of (7)Be and low concentrations of (210)Pb; 2) high concentrations of (210)Pb and low concentrations of (7)Be and 3) high concentrations of (7)Be and (210)Pb.

Behavior of ambient concentrations of natural radionuclides (7)Be, (210)Pb, (40)K in the Mediterranean coastal city of Málaga (Spain).

During a 4-year period (January 2009–December 2012), the 7Be, 210Pb, and 40K activity concentrations in airborne particulate matter were weekly determined at the Málaga (Spain) located in the southern Iberian Peninsula. Totally 209 polypropylene filters were analyzed in the mentioned period. In 100xa0% of the filters, 7Be and 40K activity concentrations were detected while 210Pb activity concentration was detected in 96xa0% of the filters. The results from individual measurements of 7Be, 210Pb, and 40K concentrations were analyzed to derive the statistical estimates characterizing the distributions. Principal components analysis (PCA) was applied to the datasets and the results of the study reveal that aerosol behavior is represented by two principal components which explain 73.2xa0% of total variance. Components PC1 and PC2 respectively explain 46.0 and 27.2xa0% of total variance. PC1 was related positively to dust content, 7Be and 40K concentrations and negatively to sunspot numbers. In contrast, PC2 was related positively to temperature and 210Pb activity and negatively to precipitation and relative humidity. The 7Be levels showed a significant correlation with sunspot numbers due to the cosmogenic origin. 40K activities showed a good correlation with dust deposition in filters mainly because it was transported to the air as resuspended particle from the soil. An inverse relationship was observed between the 210Pb concentrations and monthly rainfall, indicating washout of atmospheric aerosols carrying these radionuclides and a pronounced positive correlation with the average monthly temperature of air.

Study of the cosmogenic factors influence on temporal variation of 7Be air concentration during the 23rd solar cycle in Málaga (South Spain)

Atmospheric 7Be activity concentrations were measured in Málaga (South Spain) during the period 1997–2007. Monthly concentrations of 7Be ranged between 2.47 and 8.12xa0mBqxa0m−3 showing seasonal trend with maxima in spring–summer time. Influence of solar activity, cosmic rays and aerosol optical depth on airborne 7Be was analyzed. Weak negative correlation between sunspot number and 7Be is found. Instead, both solar energetic protons >100xa0MeV and cosmic rays show positive weak significant correlation with this radionuclide. Meteorology may contribute to the low correlation coefficients found. Aerosol optical depth exhibits significant correlation with 7Be, confirming that this radionuclide attaches to atmospheric particles.

Factors controlling temporal variability of gamma radionuclides and major-ions of bulk deposition in Málaga

AbstractnConcentrations of both gamma radionuclides as well as major ions in bulk deposition samples were measured monthly from January 2005–December 2013 and January 2007–December 2013 respectively. The gamma radionuclides present are 7Be, 210Pb and 40K (50xa0% of the samples), while ions in bulk deposition were dominated by Ca2+, Cl−,

Variables influencing the gross alpha and gross beta activities in airborne particulate samples in Málaga, Spain

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Seasonal variations of radon and the radiation exposure levels in Nerja cave, Spain

SO42- and Na+. Principal component analysis, enrichment factor and source assessment were performed to identify possible common sources. The time series of radionuclides and ions showed seasonal pattern and dependence mainly with number of African outbreaks, temperature and rain. Relatively poor correlations were observed between radionuclides and major ions.

Gross alpha, gross beta activities and gamma emitting radionuclides composition of rainwater samples and deposition to ground

The monthly bulk depositional fluxes of three natural radionuclides (7Be, 210Pb and 40K) were measured at a Mediterranean coastal station (Málaga) over an 11-year period from 2005 to 2015. The mean annual depositional fluxes of 7Be, 210Pb and 40K were 1215, 144 and 67 Bq m-2 year-1 respectively, showing a clear seasonal trend with minimum values recorded during summer and maximum values in winter. The rainfall regime with dry summers allows estimating the dry deposition. Assuming constant dry deposition through each year, 7Be, 210Pb and 40K would account for 12.5, 26.5 and 33% of the bulk fallout respectively which indicates that deposition for 210Pb and 40K are significantly higher than 7Be. The precipitation-normalized enrichment factor alpha used to explain seasonal variations in the depositional fluxes of radionuclides with respect the rainfall, indicates higher depositional fluxes during spring and summer than expected from the amount of rainfall. Despite their different origin, 210Pb and 7Be monthly depositional fluxes have strong correlation. The atmospheric deposition fluxes of 7Be, 210Pb and 40K were controlled mainly by the amount of rainfall (rxa0=xa00.89, 0.91 and 0.66 respectively). Moreover, principal component analysis was applied to the datasets and deposition of radionuclides and rainfall in the same component highlighting the importance of the washout mechanism. The mean depositional velocity of aerosols evaluated using 7Be and 210Pb are similar and are compared to other published values.