The effect of industrial air – borne pollutants on the durability of galvanized iron roofs in the tropical humid region of Nigeria

This paper examines the influence of atmospheric pollutants on one widely used building material, the galvanized iron roofing sheets, in the highly polluted region of Niger Delta of Nigeria. The study involved the atmospheric exposure of cut pieces of galvanized iron sheets to determine the influence of sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter (all by-products of gas flaring) in a humid tropical environment. The pollutants were in the mean concentrations of 0.09 – 0.68mg/l (SO2), 0.01- 0.35mg/l (NO2) and 7.22 – 20.653g/m3 (aerosol). The readings of concentration of the pollutants were recorded and multiple regression analysis was performed on the data. After one year of exposure of the specimens, it was discovered that corrosion was enhanced by the presence of these pollutants. Examination of the partial coefficients of the pollutant revealed that, nitrogen dioxide (r = 0.460) and particulate matter (aerosols) (r = 0.569) were found to correlate positively with corrosion in a multi-pollutant situation. However, it was found that sulphur dioxide (r =-0.213) did not positively contribute to corrosion impact, contrary to established results from temperate regions. It is recommended that the Nigerian Government should legislate to stop gas flaring in the region. KEYWORDS: Gully erosion, threshold, Ikpa river, coastal plains, morphometry, intrinsic factors