Spatial Analysis of Environmental Noise and Auditory Health of Abeokuta Residents, Ogun State, Nigeria

This study assessed environmental noise levels, mapped the spatial pattern at different times of the day and examined the association with morbidity of auditory ailments in Abeokuta metropolis. The entire metropolis was divided into 80 cells (areas) of 1000 m²; out of which 33 were randomly selected for noise levels assessment. Portable noise meter (AR824) was used to measure noise level and Global Positioning System (Garmin GPS-72H) was employed to take the coordinates of the sample sites for mapping. Risk map of the noise levels were produced using Kriging interpolation techniques based on the spatial spread of measured noise values across the study area. Data on cases of hearing impairments were collected from four major hospitals in the city. Data collected from field measurements and medical records were subjected to descriptive (frequency and percentage) and inferential (Mean, ANOVA and correlation) statistics using SPSS (version 20.0). ArcMap 10.1 was employed for spatial analysis and mapping. Results showed mean noise levels range at morning (42.4±4.14 – 88.2±15.1 dBA), afternoon (45.0±6.72– 86.4±12.5 dBA) and evening (51.0±6.55–84.4±5.19 dBA) across the study area. The interpolated maps identified Kuto, Okelowo, Isale-Igbein and Sapon as high noise risk areas. The monitored noise levels varied significantly among the sampled areas at morning, afternoon and evening (p <0.05). Significant correlation was found between diagnosed cases of auditory ailments and noise levels measured in the morning (r=0.39 at p<0.05). Common auditory ailments found across the metropolis included impaired hearing (25.8%), tinnitus (16.4%) and otitis (15.0%) respectively.