Dataset on noise level measurement in Ota metropolis, Nigeria

Datasets contained in this article are noise level measurement carried out at 41 different locations in Ota metropolis, Nigeria. The noise readings were measured at a time interval of 30 min for each site considered using a precision grade sound level meter. The analysis was based on the noise descriptors LAeq, L10, L90, LD, TNI and NEI. Results from the study reflects that the highest and lowest equivalent noise levels (LAeq) were recorded at commercial areas (96 dB (A)) and residential areas (52 dB (A)), respectively, the background noise level (L90) has the highest and lowest values at commercial areas (77 dB (A)) and residential areas (44 dB (A)), respectively and the peak value (L10) has the highest value and lowest value at the commercial areas (96 dB (A)) and residential areas (56 dB (A)). Based on the WHO recommendations and standards, only 2 out of the 41 locations considered are under normally acceptable situation while the noise levels of other areas are not acceptable. Noise map developed in this study provides enough information for technical controls and interim legislation against environmental noise pollution in the metropolis. Moreover, considering the noise emission standards, planning and promoting the citizens awareness about the high noise risk could help to mitigate the effect of noise in Ota, Metropolis. The noise data in this study are useful as reference and guideline for future regulations on noise limit to be implemented for urban areas in Nigeria and developing countries at large.


a b s t r a c t
Datasets contained in this article are noise level measurement carried out at 41 different locations in Ota metropolis, Nigeria. The noise readings were measured at a time interval of 30 min for each site considered using a precision grade sound level meter. The analysis was based on the noise descriptors L Aeq , L 10 , L 90 , L D , TNI and NEI. Results from the study reflects that the highest and lowest equivalent noise levels (L Aeq ) were recorded at commercial areas (96 dB (A)) and residential areas (52 dB (A)), respectively, the background noise level (L 90 ) has the highest and lowest values at commercial areas (77 dB (A)) and residential areas (44 dB (A)), respectively and the peak value (L 10 ) has the highest value and lowest value at the commercial areas (96 dB (A)) and residential areas (56 dB (A)). Based on the WHO recommendations and standards, only 2 out of the 41 locations considered are under normally acceptable situation while the noise levels of other areas are not acceptable. Noise map developed in this study provides enough information for technical controls and interim legislation against environmental noise pollution in the metropolis. Moreover, considering the noise emission standards, planning and promoting the citizens awareness about the high noise risk could help to mitigate the effect of noise in Ota, Metropolis. The noise data in this study The data contained herein can help to establish environmental noise impact criteria levels for various land use purposes. These criteria levels would enable impacts to be determined.
The given data will show researchers in the field of environmental management and sustainable city development the trend of noise pollution as it relate to commercial activities, industrial activities and traffic volume in urban areas.
The data on noise level measurement can be used in creation of a database for urban planning with localisation of noisy activities and mixed and sensitive zones.
The data can be used to evaluate population exposure to noise pollution in urban area.

Experimental design, materials and methods
The noise measurements were made at the street level (at road junctions/busy roads, commercial centres, industrial areas and residential areas). The instrument (sound level meter) used was held comfortably in hand with the microphone pointed at the suspected noise source at a distance not less than 1 m away from any reflecting object. L Ai (A-weighted instantaneous sound pressure level) measurements were recorded at intervals of 30 s for a period of 30 min, giving 60 readings per sampling location. This procedure was carried out for morning (7:00-8:00 a.m.), afternoon (1:00-3:00 p.m.) and evening (6:00-8:00 p.m.) measurements. From these readings, commonly used community noise assessment quantities such as minimum noise level (L min ), maximum noise level (L max ), equivalent A-weighted sound pressure level (L Aeq ), Noise Pollution Level (LNP), Traffic Noise  States the elaboration of noise maps for cities with more than 250,000 inhabitants, this was due on 30 June 2007 [4,5]. Based on this directive, Ota metropolis with population of over 527,242 inhabitants is qualified to be presented with noise map. In this study, ArcGIS 10.5 Software was used to develop the spatial variability mapping of Ota with the use of Inverse Diverse Weighting (IDW) interpolation method. The codes adopted and the geographical positioning systems Coordinates for the 41 chosen locations surveyed in Ota metropolis are shown below in Table 4. Figs. 4-6 show the spatial variation mapping of noise levels in Ota metropolis for the morning, afternoon and evening periods of the day.
According to recommendation of noise levels for specific environments by WHO 2002 (in Arokoyu et al. [6] and Usikalu and Kolawole [7]), all the locations surveyed in this study are categorized based on the noise maps developed into three different zones which are (a) low risk zone (May and baker location) (b) Moderate risk zone (Iyana-Iyesi market, Ilogbo road area, Tower aluminium area, Bells University drive) and (c) High risk zone (Sango under bridge, Oju Ore, Canaan Land area, Nestle area, Idiroko road, Estate and other locations with L Aeq exceeds 81 dB (A)).