Time variation of trace elements in airborne particles in San Jose, Costa Rica

We have measured trace elements in airborne particles to identify possible pollution sources at San Jest, Costa Rica. Time sequence streaker aerosol s amplers were operated over a week period for each site chosen. The aerosol was collected in one size fraction on a Nucleopore membrane. PIXE was used to analyze the concentration of 14 elements detected. Samples were irradiat ed with 3.2 MeV protons using the 4 MV Van de Graaff accelerator of Florida State University. Ambient aerosols contain fine sulfur, marine and several distinctive soil components. About 85% of the particles are formed by soil dust and automobile combustion, with some elements from the marine breeze. The average values for all elements (except Si) are less than 1 mu g/m(3)