Spatiotemporal assessment of aerosol optical depth and the sky conditions in Ikeja and Benin City, Nigeria

Abstract

The challenge in mitigating pollution as a result of anthropogenic activities remains a mirage if there is no spatiotemporal assessment of the trend of aerosol optical depth (AOD), hence this study examines the trend of aerosol optical depth and its sky condition. The data for AOD was obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) for the two locations (Ikeja and Benin City), in the coastal zone of Nigeria. The data was classified into dry and rainy season. Mann Kendal trend test and trend equation were employed to ascertain trend of AOD for 22 years and to predict its future trend. The results for both rainy and dry season showed that there were no significant differences in AOD (p= 0.5313 and 0.9830 for Ikeja, 0.3121 and 0.3665 for Benin city, whereas the trend line for the two locations show infinitesimal slope (Ikeja =-0.0003 and -0.001, Benin city=0.00007 and 0.0017) for both rainy and dry season, so insignificant to predict the future AOD trend of the locations. The result also shows that the two locations experienced a very clean sky in the month of May, June, July, August, September and October, whereas January, February March were hazy sky.