Spatial Analysis of Atmospheric Pollutants from Rumuolemeni Landfill, Port Harcourt using GIS

Abstract

The study identified spatial variation of air quality status in the vicinity of the landfill site in Rumuolumeni. Air quality parameters of nitrogen oxide (NO₂), sulphur dioxide (SO₂), methane (CH₄), volatile organic compounds (VOC), ammonia (NH₃), hydrogen sulphide (H₂S) and weather parameters of temperature, relative humidity, wind speed, wind direction, were collected with respect to distance from the center of the dumpsite into the residential area at various locations for seven days using composite sampling technique. Global Positioning System (GPS) was used to determine the longitude (y-coordinate) and latitude (x-coordinate) of each location which was used with the air quality and weather parameters to determine the areas of equal concentration of air quality through the method of interpolation in ArcGIS 9.3 environment. The spatial coverage of levels of concentration of each air quality parameters was calculated in hectares (ha) in ArcGIS 9.3 environment. The GIS analysis showed that the spatial coverage of the entire study area was 1.128 sq km. Result indicates that concentrations of NO₂ in the study area varied spatially; values ranging between 0.034mg/m³ and 0.042mg/m³ covered 0.217sq km while the range between 0.026mg/m³ and 0.033mg/m³ covered 0.194sq km and much of this spatial coverage was within the built up area of the study area. However, the concentration of VOC between 0.543 and 0.813 mg/m³ had a spatial coverage of 0.019 sq km while the higher levels of concentration between 2.432 and 0.2.971 covered 0.027 sq km. The concentration levels of VOC between 1.353 and 1.622 mg/m³ covered 0.267 sq km, 1.893 and 2.162 covered 0.150 sq km and 1.623 and 1.892 mg/m³ covered 0.280 sq km. There was no general pattern between the level of concentration of VOC and the spatial coverage. The spatial coverage of the concentration of SO₂ range of values of 0.187 and 0.373 mg/m³ was 0.413 sq km. The mean value of wind speed at the dumpsite was 0.22m/s while it was 0.25m/s in the residential area. This indicates that the pollutants have the tendency to stagnate over time in the vicinity of the landfill. It is recommended that the landfill be closed given the rate of urban sprawl to avoid the unhealthy consequences of inhaling these toxic gases.

Keywords: Pollutant concentration, GIS, ArcGIS 9.2, interpolation, meteorological parameters.