Measurements of the concentration of 210Pb and 7Be in all aerosol samples collected as part of the standard AEROCE protocol at all primary and secondary sites and the monthly deposition flux of 210Pb and 7Be to all primary and secondary sites will be conducted. These nuclides have well-known sources and do not undergo chemical transformations. There are 4 objectives: 1) The observed concentrations and deposition of these nuclides will be used to test and refine both event-oriented and climatological numerical models of atmospheric transport. 2) The correlations between the radionuclides and other species will be used to infer the sources of the other species and of seasonal changes in source or transport. 3) The ratio of deposition rate to surface air concentration will be used to measure the transfer rate of aerosols to the surface. 4) The 7Be/210Pb ratio will be tracked as a potential measure of both the vertical mixing in the troposphere and the altitude of aerosol removal.
