Design, Construction and Evaluation of a Multi-Stage “Cassette” Impactor

A cascade impactor, (fabricated from 37-mm cassette pieces) is described. The sampler can be built in a few hours using simple machining operations. Construction details are provided. The unit is small and light enough to be used for personal as well as area sampling. The impactor has been compared with commercially available units under a variety of laboratory and field conditions and agreement has been good. Precision of replicate samples has also been good. The unit was calibrated using the TSI aerodynamic particle sizer and results are in general agreement with theoretical 50% cut points using three different collection substrates.