ELEMENTAL ANALYSIS AND SOURCE APPORTIONMENT OF AMBIENT PARTICULATE MATTER AT MASTERTON, NEW ZEALAND

At certain locations in the Wellington Region, pollution episodes due to air particulate matter are known to occur from time to time. Traditional gravimetric analysis of airborne particulate matter is unable to provide information on the sources contributing to air particulate concentrations. Ion Beam Analysis (IBA) is one of the few non-destructive techniques that can be used to identify the elemental composition of air particulate matter on a filter sample. In this work IBA was used to characterise air particulate matter in two size fractions, PM20. and PM10-2.0, collected at a monitoring station in Masterton, New Zealand. Elements with atomic mass above neon were measured by the PIXE technique. Elemental carbon was measured with a light reflectance device. Elemental 'fingerprints' of contributing sources were determined by performing factor analysis of the elemental composition. The results indicate that 'Sea Salt' and 'Soil' sources are major contributors to the coarse (PM10-2.0) fraction and 'Combustion' sources dominate the fine (PM2.0) fraction of air particulate matter. Analysis of seasonal differences was a useful tool in elucidating source profiles.