Spatial and temporal distribution of lead-210 in the surface layers of the atmosphere

The levels of 210Pb in surface air from about sixty locations and in rainwater from about forty locations, around the globe, are summarised. The spatial, annual and long-term variations in the levels of 210Pb are discussed. The concentrations vary as a function of the continentality of the locations and at many stations there is a seasonal variation. There is no significant long-term variation in activity levels, possibly indicating the absence of a major anthropogenic source of this nuclide. The activity ratio of 222Rn/210Pb is around 6000 in India and varies seasonally depending on air mass source. (author)