ENERGY-DISPERSIVE X-RAY-FLUORESCENCE SPECTROMETER WITH CAPILLARY OPTICS FOR THE CHEMICAL-ANALYSIS OF ATMOSPHERIC AEROSOLS WITH HIGH TIME RESOLUTION

A new method is presented for the chemical analysis with high time res olution of atmospheric aerosols deposited on a filter surface. The aer osols are collected with a special streaker sampler. This device draws the air by a 8 x 1 mm rectangular orifice through a Nuclepore polycar bonate membrane filter. The filter is mounted on a circular frame,:whi ch relates at 1 revolution per week. The particulate matter is deposit ed as a 8 mm wide ring. The deposit oil the filter is analysed in 1 mm steps, each corresponding to 1 h of exposure. Analysis of the filters is performed using an energy-dispersive X-ray fluorescence (EDXRF) sp ectrometer comprising an X-ray tube with Mo or Cr anode, a glass capil lary with inner diameter of 1 mm, a sample holder with a rotational st age and a Si (Li) semiconductor detection system. The detection limits in capillary optics EDXRF of streaker samples are compared with those obtainable in particle-induced X-ray emission (PIXE) and with atmosph eric particulate levels observed in urban areas. The potential of the method of aerosol studies in urban and polluted environments is illust rated by the analysis of samples collected at two sites in the city of Cracow. (C) 1997 Elsevier Science Ltd. All rights reserved.