A new approach to sampling for particle size and chemical species 'fingerprinting' of workplace aerosols

A commercially-available, high-volume (28.3 Lpm) Andersen-type cascade impa ctor was modified in order to extend its operational range further into the range of large inhalable particles for purposes of use in an exposure asse ssment study in the primary nickel production industry. The modification in volved incorporating a 10-ppi (pores per inch) porous plastic foam top stag e that has a wide penetration curve with a (50)d(ae)-value of approximately 27 mum. This enabled the upper end of the range of the instrument to be ex tended from about 10 to greater than 70 mum. The inlet of the original inst rument was also modified to incorporate the new top stage and provide 'repr esentative' aspiration of total airborne particulate with an efficiency of close to 100% over the range of aerodynamic particle sizes of interest. A m athematical inversion algorithm developed in earlier research was modified so that it could be applied to this new instrument. This enabled raw data o n particulate material recovered from all stages of the Instrument (includi ng the new porous foam top stage) to be used for the determination of conti nuous particle size distributions, as well as chemical speciation, over the inhalable range. The new instrument was deployed in a pilot field study in the nickel primary production Industry by which to demonstrate the potenti al of the new instrument for generating useful information pertaining to he alth-relevant aerosol size tractions (e.g., inhalable, thoracic, and respir able), and for soluble, sulphidic, metallic, oxidic and total nickel chemic al species groups. (C) 2001 British Occupational Hygiene Society. Published by Elsevier Science Ltd. All rights reserved.