Factors influencing ambient concentrations of 210Pb and 7Be over the city of Edinburgh (55.9°N, 03.2°W)

The effect of air mass origin on the ambient concentrations of 7Be and 210Pb in Islamabad, Pakistan

“…A number of different researchers have predicted that the concentration of 7 Be in surface air is maximum during spring time in the northern hemisphere (e.g. Baskaran, 1995;Koch and Mann, 1996;Likuku, 2006). The main reason for that is the enhancement in transport of air masses, enriched with 7 Be, from the top of the troposphere and stratosphere to the earth surface in spring season due to pressure gradient.…”

“…The main source of 222 Rn and its decay products is the underground soil, from where they are released into the atmosphere through molecular diffusion and interstitial flow. The long lived natural radionuclide 210 Pb (T 1/2 ¼ 22.3 years) is produced in the atmosphere near the surface level by the radioactive decay of its precursor 222 Rn which is released from the ground to the atmosphere, predominantly from ice-free continental surfaces (Likuku, 2006). 7 Be is a relatively short lived (T 1/2 ¼ 53.29 days) and naturally occurring radionuclide of cosmogenic origin, formed in the upper troposphere and lower stratosphere by the spallation of oxygen and nitrogen nuclides (Lal and Peters, 1967).…”

“…Because of its cosmogenic origin, the main production site of 7 Be is in the lower stratosphere at a height of about 20 km. 7 Be production has negligible dependence on season and longitude but its surface air activity shows a strong dependence on altitude, latitude, local climate and seasonal variations (Hötzl et al, 1991;Gerasopoulos et al, 2001;Due nas et al, 2005;Daish et al, 2005;Likuku, 2006;Abe et al, 2010). Once 7 Be and 210 Pb are produced, they are highly particle reactive and thus are attached to the sub-micron sized aerosol particles (Papastefanou and Ioannidou, 1995;Church and Sarin, 2008).…”

“…The data obtained from different studies around the world have revealed seasonal variations in the ambient concentration of 7 Be. These seasonal variations depend on the rate of exchange of air between the stratosphere and the troposphere (Dutkiewicz and Husain, 1985;Feely et al, 1989), the rate of vertical mixing within the troposphere (Graustein and Turekian, 1996), the rate of pole-ward transportation of air masses from middle to high latitudes (Feely et al, 1989) and the rainfall rates (Baskaran et al, 1993;Likuku, 2006). As 7 Be is of cosmogenic origin and its production rate is high in the upper troposphere, its concentration in the air increases with increasing altitude from the surface of the earth.…”

Measurements of Lead-210 Activity Concentration in the Ground-Level Air in Finland and Bulgaria

“…The monthly variation of 210 Pb in Serbia, reported in [15] for the period 2011-2012, show spring minimum, maximum in November followed by the low values for December and January. Specific seasonality is observed in Edinburg [16] The tendency of decrease in 210 Pb concentration reported previously in [7] for the beginning of the 21st century is not followed during the years 2006-2007, Table 1.…”