Abstract:
Airborne particulate matter (APM) composition has been studied at the Abuesi area. Aerosol samples in two size fractions were collected over a period of 3 months using the Gent stacked filter unit (SFU). Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) was used to measure concentrations of up to 28 elements at the INFN-Accelerator Laboratory, University of Florence, Italy for the coarse fraction which accounted for 53.84 % of PM10 aerosols in the Abuesi area. Mean values of 41.890 μg/m³, 22.469 μg/m³ and 19.422 μg/m³ were measured for Inhalable Particulate Matter (IPM/PM10), Coarse mode Particulate Matter (CPM) and Fine mode Particulate Matter (FPM) respectively and these were within the World Health Organisation (WHO) guidelines. Chlorine is established as an important component of the aerosol in Abuesi, originating mainly from sea spray. It accounted for 32.13 % of the total coarse mode aerosol elemental concentration. Characterisation of aerosols in the study area was performed using Principal Component Analysis (PCA) with VARIMAX rotation. Six factors score accounted for the three main identified APM sources (i.e. crustal material/soil dust, marine/sea spray and mechanical operations) in the area with crustal material/dust representing the dominant source. Enrichment Factor (EF) values also showed no enrichment for about 86 % of the measured elements with only Na which resulted predominantly from sea spray recording a moderate enrichment score of EF=3.386. The results obtained suggest that ambient air quality in the Abuesi area is safe. There is, however, the need to conduct further studies to estimate the black carbon concentrations of both fine and coarse aerosol fractions and, as well, investigate the elemental source profile of the various APM sources in the study area.
