Possible sources of atmospheric aerosol during 2005/06 Harmattan season at Kwabenya (Ghana)

Principal component analysis has been used to characterize and model aerosol particulate matter collected during the 2005/06 harmattan period. Species parameters determined by gravimetric, energy dispersive X-rays fluorescence (EDXRF) and reflectometric techniques were mass, elemental and black carbon concentrations. More than 26 elements were identified in the aerosol samples, but only 17 were used for the coarse fraction and 7 for the fine fraction models, because of detection limitation or missing values. The coarse fraction contained over 90 % of the mass, but the fine particle fraction has higher contribution of black carbon particles than the coarse fraction. Two source profiles were identified in the fine fraction of the aerosol and four source profiles in the coarse fraction. The experimental and modeled particulate mass correlated well, with 0.93 ≤ R2 ≤ 0.95. Journal of Applied Science and Technology Vol. 13 (1 & 2) 2008: pp. 55-6

The Determination of Mass, Element and Black Carbon Concentrations in Harmattan Aerosol Samples Collected at Kwabenya, Ghana

Aerosol particles were sampled between 27th December 2005 to 16th February 2006, using the Gent sampler and segregated into two size fractions – fine (PM2.5) and Coarse (PM10-2.5) from Kwabenya, near Accra. The aerosol particles were collected on Nuclepore polycarbonate mem-brane filters. The mass, Black Carbon (BC) and elemental concentrations in the two size frac-tions were determined using Gravimetric analysis, black smoke method and EDXRF analysis, respectively. The aerosol mass concentration was 8.57 μg/m3 for the fine fraction and 110.90 μg/m3 for the coarse fraction. The average Black carbon concentrations measured were 0.71 μg/m3 and 0.65 μg/m3 for the fine and coarse fractions, respectively. The results were compared with some literature values and the World Health Organisation Standard values. The high coarse to fine ratio suggest that most of the aerosol are from natural sources