Elemental Analysis of Aerosol in Singapore Atmosphere by Nuclear Analytical Techniques

Abstract

Results of elemental analysis of aerosol samples collected during June 1994 at two locations in Singapore are reported. More than 200 samplers were collected using cascade impactor during a two-week sampling period. The samples were analyzed by means of Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering (RBS) techniques. Multivariate statistical analysis was used to identify the major source of pollutants. It was found that the dominant component at one of the sampling site was of natural origin and at the other of anthropogenic origin. Diurnal variation was observed to be large and greatly dependent on meteorological conditions. Our results also show that the air quality in Singapore remains good. Sulfur is the main anthropogenic pollutant and its concentration in the Singapore atmosphere varies about its mean value of 1500 ng/m3, which is still well below the acceptable limit stipulated by the United States Environmental Protection Agency (USEPA). The concentration of lead is still decreasing —from 700 ng/m3 in 1984 to 100 ng/m3 in 1991 and down to 50 ng/m3 obtained in recent measurements.