A LABORATORY RESUSPENSION CHAMBER TO MEASURE FUGITIVE DUST SIZE DISTRIBUTIONS AND CHEMICAL-COMPOSITIONS

A laboratory resuspension chamber is described that segregates dried and sieved geological material into size fractions less than 0, 1.0, 2.5, 10 and similar to 30 pm aerodynamic diameters onto filter media suitable for chemical analysis. Eight impactor inlets located in a rectangular array within a 0.4 m(3) chamber provide the size segregation. Tests show that mass concentrations across the array vary by no more than +/-10%. Filter samples are normally submitted to gravimetric, X-ray fluorescence, ion chromatography, automated colorimetric, atomic absorption spectrophotometric, and thermal/optical reflection analysis for similar to 50 chemical species. Chemical profiles and size distributions have been measured on more than 200 dust samples throughout the world.