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

Abstract

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 (7Be and 210Pb) as tracers of these intrusions are discussed. The origin of these radiotracers is completely different. 210Pb is a good tracer of air masses traveling close to the ground and come from inland areas. On the other hand, the production of 7Be is very low in the vicinity of the Earth's 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 7Be and 210Pb 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 7Be and 210Pb 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 7Be and 210Pb: 1) high concentrations of 7Be and low concentrations of 210Pb; 2) high concentrations of 210Pb and low concentrations of 7Be and 3) high concentrations of 7Be and 210Pb.