Statistical Analysis of Traffic Noise Status at Selected Junctions in Port Harcourt Metropolis

Abstract

Traffic noise is one of the dominant forms of environmental pollution in most urban cities that adversely affect human health globally. The traffic noise emanating from motor vehicles has become a common health problem in many metropolitan cities in developing countries of the world. This study evaluated traffic noise at selected major junctions (Rumuola, Garisson, Boro Pack, and Lagos Bus stop) in Port Harcourt Metropolis. Traffic noise levels at four congested junctions and a control junction in the Metropolis were monitored using a digital sound level meter. Noise indices, L10, L50, L90 equivalent noise levels (Leq), noise climate (NC), noise pollution index (NPI); traffic noise index (TNI); noise pollution level (Lnp); day-evening-night equivalent metric (LDEN) and percentage highly annoyed (%HA) were statistically determined. Traffic noise at Rumuola junction showed traffic noise ranging from 51.9 to 107.9dBA with a mean deviation of 91.3±8.4dBA; traffic noise at Garrison junction ranged from 52.8 to 107.6dBA with a mean deviation of 88.5±9.7dBA; Boro Park junction showed traffic noise ranging from 48.9 to 106.4dBA with a mean deviation of 83.7±10.1dBA; Lagos Bus Stop junction ranged from 45.4 to 94.9dBA with a mean deviation of 81.5±10.8dBA; while the Control junction (Ibadan Street junction)showed a traffic noise ranging from 48.4 to 61.3dBA with a mean deviation of 51.6±5.3dBA. Noise levels at the studied junctions were significantly high and exceeded permissible limit compared to the control junction (p-value = 0.00485; 95%CI). L10 (94.8dBA), L50 (86.8dBA), L90 (76.1dBA) and Leq (92.4dBA) were highest at Rumuola junction and lowest at Control junction (with 57.3dBA, 52.8dBA, 48.4dBA and 54.1dBA, respectively). Computed NPI values (1.25-1.34) indicated high traffic noise levels at the four junctions and low (0.77) at the control junction; Lnp values (105.0-116.6dBA) indicated high traffic noise pollution at the four junctions and low (63.0dBA) at the control junction; TNI values (120.9-138.5) indicated high traffic noise impacts at the four junctions and low (54.0) at the control junction. Computed LDEN and %HA indicated high level of traffic noise annoyance to the four junctions. The study revealed high traffic noise pollution at the four junctions that may significantly affect public health and therefore requires further investigation by concerned authorities to assess the health effects of traffic noise on the surrounding residents and traders at the studied junction.