Determination of the size distribution of carbon and trace elements in suspended particulate matter by ion beam analysis

Abstract

The size distribution of carbon and trace elements in suspended particulate matter (SPM) collected by a low pressure impactor has been investigated. Sampling was carried out at Setagaya, a typical residential area located southwest of Tokyo, Japan. The low pressure impactor has a cascade design with 12-stage collection plates, allowing the collection of size-fractionated SPM. It operates at a flow rate of 20 l/min. Elemental composition was determined by ion beam analysis, particle induced X-ray emission (PIXE) and Rutherford backscattering (RBS). PIXE provided data for elements from Al to U while RBS supplied information on elements lighter than Al such as C and O. The analysis is fast, non-destructive and requires no sample preparation. It is very suitable for determination of elements in SPM. In this paper we discuss size distribution and element concentrations in SPM together with their weekly and seasonal variations.