The concentrations, distribution and sources of cadmium, copper, lead and zinc in the atmosphere of an urban environment.

The four metals Cd, Cu, Pb and Zn have been measured in residential city air in a relatively small urban environment. The atmospheric concentrations are Cd, 0.516, 0.305; Cu, 12.5, 8.22; Pb, 155, 70.2; and Zn 47.4, 22.4 ng m-3 at two different sites. Except for lead the concentrations are low and more typical of rural areas in more industrialised centres. The concentrations were found to be higher in the colder and more stable air conditions existing during the winter season. Also concentrations on the flat were higher than those on a hillside probably reflecting the influence of thermal inversions. Wind direction influences the concentrations, they being greater when the wind flow comes across the industrial areas of the city. Some of the major sources of the elements are coal, soil, tyre wear and automobile emissions.