Evaluation and spatial noise mapping using geographical information system (GIS): A case study in Zaria city, Kaduna State, Nigeria

Spatial noise level mapping using a geographical information system (GIS) is essential for the visual colour representation of noise analysis, which is a necessity for strategic planning and mitigating measures.

Extech noise meter (model 407750) was used for sound measurement and a GIS (inverse distance weighted) was used in 54 study locations for the spatial interpolation. The study was classified into five categories based on Nigeria’s WHO standard and National Environmental Standards and Regulations Enforcement Agency (NESREA).

For the LDAY (D), LEvening (E), LNight (N), and LDEN, all the locations exceeded the WHO standard while 94.4%, 90.7%, 83.3%, and 83.3% of the locations exceeded the NESREA standard. The LDay (D) ranged from the minimum value of 67.6 dB (A) at the Ijaw residential area to the maximum value of 93.0 dB (A) at Kwangila site (1) intersection. The LNight ranged from the minimum value of 63.3 dB (A) at Dogorawa residential area to the maximum value of 92.1 dB (A) at Kwangila site (1). The LDEN ranged from the minimum value of 73.1 dB (A) at Hanwa residential areas to the maximum value of 97.2 dB (A) at Kwangila site (1). The noise quality rating ranged from satisfactory to unallowed noise quality grading. The selected intersections and residential areas with light commercial activities had the highest and lowest noise levels, respectively.

Efficient maintenance of silencers, planting trees with dense foliage, and strategic planning would be necessary panacea in curbing excessive noise.