A detailed method used for assessing and mapping noise pollution levels in Ota metropolis, Nigeria using ArcGIS 10.5 Software is presented in this paper. Noise readings were measured at a time interval of 30 min for each site considered using a precision grade sound level meter. The noise map developed was based on the computed values of average equivalent noise (LAeq) for the selected locations. Results of this study show that the A weighted sound level (LAeq), the background noise level (L10) and the peak noise level (L90) vary with location and period of the day due to traffic characteristics especially traffic volume, vehicle horns, vehicle mounted speakers, and unmuffled vehicles at road Junctions, major roads, motor parks and commercial centres. Based on the U.S. Department of Housing and Urban Development (HUD) recommendations and standards, only one (1) out of the 41 locations considered is under normally acceptable situation, while 12 locations are under normally unacceptable and the noise levels of the rest locations are clearly unacceptable. Results of this study are useful as reference and guideline for future planning and regulations on noise limit to be implemented for urban areas like Ota Metropolis. •Instrumentation used in this study for the environmental noise measurements consisted of a precision-grade sound-level meter - Model 8922 RS232.•The Geographical Positioning System (GPS) device (model: Magellan eXplorist 310) was used to obtain the exact coordinates of each location where noise level readings were recorded.•ArcGIS 10.5 software was used in this study to develop noise map for Ota Metropolis.
Keywords: A GIS – based method for developing noise map; Background noise; GPS; Noise descriptors; Noise map; Noise pollution level; Peak noise.