Non-destructive neutron activation analysis of atmospheric pollutants

Concentration of elements in atmospheric particulate of urban areas has been determined by employing a Ge(Li) detector. In the first part of this study, a single area was selected and samples were collected on millipore filter during three seasons of the year and their results were compared. It was concluded that in a dry climate at least two parameters are involved in seasonal changes of trace elements in the atmosphere. They are the rate of wet deposition and reduction of vertical diffusion of airborne particulates. The results have been compared with results obtained for other cities abroad. Wraymires site was selected as a clean area by PEIRSON because it was away from industrial activities and was therefore relatively unpolluted. With the exception of Na, the concentration of all elements in air in other cities exceed those reported for Wraymires. The concentrations shown for Tehran are generally in agreement with results quoted for other large cities. (T.G.)