Assessment of Ambient Air Pollution Pattern in Ikpeshi Community Edo State Nigeria Using Geostatistical Analysis

Abstract

Understanding the Spatial distribution of ambient air quality in an active mining and solid mineral processing community is important in order to determine pollution hot spots and cold spots, as well as the trend. This will help Air Quality Managers to evaluate areas that are highly exposed to air pollution for mitigation purposes. In this study, dust particles in the form of ambient PM2.5, and PM10 were measured on weekly basis for a period of one year at 73 sampling points located in Ikpeshi, a mining and mineral processing community in Edo State, Nigeria using Double Parameter HoldPeak HP-5800D model Laser PM2.5 Meter. Geospatial data was also collected by means of Garmin GPSmap 78s model. The PM2.5 and PM10 data were preprocessed in MS Excel 2010 computer software to obtain the mean pollutant concentrations for the two parameters. The mean PM concentrations were analyzed and mapped using ArcGIS 10.0 software to generate various geostatistical surfaces to describe the ambient air pollution pattern and spatial distribution of pollutants in the community. The predicted mean concentrations ranged from 5.25 to 88.75µg/m3 for PM2.5 and 8.15 to 552.85µg/m3 for PM10. Mann-Kendall’s test showed that the observed pattern in ambient air quality exhibits a linear trend at 5% significant level with pollution hot spots found in the South-Eastern part of the community where the mills and quarries are domiciled while the cold spots appeared in the residential areas found in the North-Western part of the community. It was therefore concluded that the ambient air pollution pattern in the study area exhibits a linear south-east to north-west trend which is statistically significant at 5% level.