Exposure to coarse and fine particulate matter at and around major intra-urban traffic intersections of Ilorin metropolis, Nigeria
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Date
2017
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Publisher
Elsevier
Abstract
This study aims to determine the seasonal variations and composition of suspended particulate matter in
different sizes PM1.0, PM2.5, PM10 and the total suspended particles (TSP) emitted at major intra-urban
traffic intersections (TIs) of Ilorin metropolis. The concentration levels of PM (PM1.0, PM2.5, PM10) obtained
at the TIs during the rush hours (45.1, 77.9, and 513 mg/m3) are higher than the levels obtained for
the non-rush hour periods (42.3, 62.7, and 390 mg/m3). The average on-road respiratory deposition dose
(RDD) rates of PM1.0, PM2.5 and PM10 during the dry period at TIs types was found to be about 24%, 9%
and 25% higher than those obtained during the wet period. Based on EF values calculated, Pb and Zn were
anthropogenically-derived while Fe, Mn, Cr, Cu and Mg were of crustal source. Principal component
analysis (PCA) has been applied to a set of PM data in order to determine the contribution of different
sources. It was found that the main principal factors extracted from particulate emission data were
related to exhaust and non-exhaust emissions such as tyre wears, oil and fuel combustion sources.
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Keywords
Particulate matter, Traffic intersections, Deposition flux, Principal component Analysis, Elemental composition