Monitoring of Spatio-Temporal Dynamics of Air Pollution in Enugu Urban using Remote Sensing and GIS

Abstract

Ambient air pollution is widely acknowledged to be the worst type of environmental pollution. The amount of air pollution varies from time to time and from region to region. The spatiotemporal distribution of air pollutants in the city of Enugu was investigated in this study. Due to the high concentration of industrial clusters, heavy traffic and increasing population density in the study area, notable places were purposely sampled during the hours of 8a.m. and 4p.m. A portable gas analyzer, the Aerocet-531 Met One Instrument, Drager X-am 5000, was used to quantify the amounts of PM2.5, PM10, CO, SO2, and NO2. The GPS coordinates of the sampling spots were recorded using the portable Germin-300 Global Positioning System (GPS) device analyzer, which aided in the data processing to create spatial interpolation maps in ArcMap. GIS and remote sensing methods were utilized to analyze the spatial distribution of contaminants using satellite images. ArcGIS and Erdas Imagine were used to analyze the identification of pollution sources, the geographical distribution of pollutants in connection to land use and the epidemiological scope of pollutants from sources. The approaches employed to get the findings included image categorization, proximity, intersection, and interpolation. It was determined that there was a correlation between the landuse density and the levels of NO2, SO2, CO, PM2.5, and PM10. Within 100m – 400m of major roadways, correlation values were highest, indicating a high risk of vulnerability in this area. The maximum values for PM2.5 and PM10 were 1.78μg/m3 and 205μg/m3 respectively during the dry season and 2.13μg/m3 and 184μg/m3 during the wet weather. Similarly, the minimum values for PM2.5 and PM10 are 0.25μg/m3 and 161μg/m3 respectively during the dry season and 0.45μg/m3 and 132μg/m3 during the wet weather. The study further shows that the range values of SO2, NO2, and CO during the dry season are between 0.71 to 1.98ppb, 0.72 to 1.96ppb and 9.21 to 18.04ppb respectively while ranges of 0.45 to 1.73ppb, 0.31 to 0.89ppb, and 7.94 to 12.56ppb were recorded during the wet season. The study concluded that the high levels of PM2.5, PM10, SO2, NO2, and CO in the study area monitored especially in the dry season may present a potential public health risk. Sequel to this, it is advised that the study area should reduce their exposure in light of this, especially during the dry season.