Journal of Radioanalytical and Nuclear Chemistry, Articles, Vol. 179, No. 2 (1994) 187-194 Nuclear Analytical Methods in Atmospheric Pollution Studies ELEMENTAL CONCENTRATIONS AND SOURCE IDENTIFICATION OF AIR PARTICULATE MATTER AT A NIGERIAN SITE: A PRELIMINARY STUDY E. A. OLUYEMI? O. I. ASUBIOJO?* A. F. OLLrWOLE,2 C. J. N. TOUSSAINT 3 IDepqrtment of Chemistry, Obafemi Awolowo University, lle-lfe (Nigeria) 2Department of Physics, Obafemi Awolowo University, lle-lfe (Nigeria) 3Environmental Institute, Chemistry Div. CEC/Joint Research Centre. 21020-lspra (VA ) (Italy) Received February 3, 1994) Air particulate matter collected between July and October 1990 at a site located close to an industrial estate in Lagos, Nigeria were analyzed for 18elements by Wavelength DispersiveX-ray Fluorescence Spectroscopy(XRF) and Atomic Absorption Spectroscopy (AAS). Varimax rotated factor analysis was used for source identification of the coarse and fine fractions. For the coarse fraction, the major sourcesare: Re-entrained soil, Sca-salt, Industry, Regional sulphate and fresh automobile exhaust. For the fine fraction, the sources identified are Re-enlrained soil, Vehicle exhaust, Sea-salt, and Industrial processes. Two other sources which are likely to be due to specific industrues come out in the fine fraction but they have not been clearly identified. Environmental pollution problems which had been largely ignored in the past have now become a subject of considerable national interest in Nigeria. An agency has been established to set environmental protection guidelines and enforce compliance and the public has become more aware of environmental pollution consequences. The most conspicuous form of air pollution in the country is Suspended Particulate MattE.r (SPM), levels as high as 40,000 i~g/ma having been recorded in some industrial sites (1) and up to 1033 p.g/m a in ambient air (2). The risks posed by SPM to human health and the ecosystem in general have been well documented (3-4) hence it is important to develop effective control measures for air particulate emissions. However, an important step in an air pollution control program is the identification of the pollutants, the contributing sources, and the relative contribution of each source. Factor analysis and chemical mass balance applied to elemental concentration data have been shown to be quite useful in identifying sources and apportioning contributions of the various sources to air particulate at specific sites (5-7). In this paper, we report on the elemental concentrations of suspended particulate matter at a site in Lagos, Nigeria, and factor analysis of the results to identify the contributing sources. For this kind of study, accurate determination of the concentrations of a fairly large number of elements is required as input into the multivariate statistical programme (factor analysis) used for source identification. We have thus used the Wavelength Dispersive X-ray Fluorescence (WDXRF) technique to determine AI, Si, S, CI, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Br, and Pb and Flame Atomic Absorption Spectroscopy (FAAS) for Na. *Author for all correspondence. Elsevier Science S. A., Lausanne Akad~miai Kiadt, Budapest