Natural Radionuclides in the Atmosphere

Atmospheric fluxes of 7Be and 210Pb on monthly time-scales and during rainfall events at Stony Brook, New York (USA)

“…The ratio ranges from 10 to 28, with the lowest values (10e11) occurring during the winter 2009 (JanuaryeMarch; Table 1) and elevated values (21e28) during the spring months. This seasonal variation in 7 Be/ 210 Pb in precipitation is similar to the patterns of 7 Be/ 210 Pb documented in surface air from continental sites in North America by Turekian and Graustein (2003), who argued that lower 7 Be/ 210 Pb ratios in the winter were due to enhanced stability and reduced vertical mixing.…”

“…The 7 Be/ 210 Pb values observed in precipitation at Stony Brook are greater than those in surface air at continental sites (range w5e15) sampled by Turekian and Graustein (2003) and are more similar to those at oceanic sites (e.g. 10e30 at Bermuda).…”

“…The source of 210 Pb to the atmosphere, radon emanated from soils, is confined to the lower troposphere, while the cosmogenic production of 7 Be is enhanced in the upper troposphere. Thus the 7 Be/ 210 Pb activity ratio in precipitation is an indicator of where in the atmosphere the scavenging of these radionuclides takes place (Turekian and Graustein, 2003).…”

Scavenging and fractionation of particle-reactive radioisotopes 7Be, 210Pb and 210Po in the atmosphere

“…in 2005, respectively (Table 2), which are within the range of the global mean 210 Pb flux of $0.27-0.82 Bq m À2 d À1 reported from different estimates (Turekian et al, 1977;Turekian and Graustein, 2003;Du et al, 2008;Baskaran, 2011). Although there is large latitudinal variation in the depositional flux of 210 Pb, our estimated annual 210 Pb flux fits well with that of $0.27-0.54 Bq m À2 d À1 predicted from a global curve of Persson and Holm (2014) for the latitude of 20-30°N.…”

“…Once formed, 7 Be rapidly attaches to the fine aerosol particles in the air, enters the lower atmosphere through the vertical convective mixing/transport of air masses, and is removed from the air mainly through wet precipitations Olsen et al, 1985;Dibb, 1989;Todd et al, 1989;Benitez-Nelson and Buesseler, 1999). Due to its high particle-reactivity and unique source function, 7 Be could be used as a tracer for a wide range of processes in the atmosphere (Gaffney et al, 1994;Turekian and Graustein, 2003;Ioannidou and Papastefanou, 2006;Papastefanou, 2006;Dibb, 2007) as well as in the aquatic systems (e.g., Silker, 1972; http://dx.doi.org/10.1016/j.gca.2016.05.039 0016-7037/Ó 2016 Elsevier Ltd. All rights reserved. Young and Silker, 1980;Masqué et al, 2007;Kadko and Prospero, 2011;Cámara-Mor et al, 2011).…”