Environmental noise levels in the city of Colombo, Sri Lanka

Abstract

INTRODUCTION AND OBJECTIVES: Noise is a physical pollutant, which causes adverse health effects. Noise levels in most cities are higher than that recommended by environmental regulatory authorities of the relevant countries. Objective of this study was to determine the level of environmental noise at identified locations in the city of Colombo. METHODS: Colombo Municipal Council area is divided into 15 divisions. Sixty places with high traffic density, four from each of the 15 divisions, were purposively selected. At each selected site, equivalent continuous sound pressure level (LAeq) was measured for six hours during day time (three hours each from peak and non-peak traffic hours) using a Class-I Sound Level Meter on week days. LAeq for eight hours (LAeq [8hrs]) was calculated and taken as the average noise level of that place. L10, L50, and L90 measurements were also taken. RESULTS: LAeq (8hrs) within the Colombo city ranged from 76.6dB (at BOC roundabout, Colombo 12) to 84.0dB (at Lipton’s roundabout, Colombo 07), well above the maximum permissible noise level (63dB) for municipal council areas. All recorded LAeq values were more than 80dBs in Colombo 5, 9, 10, 13 and 14. Median LAeq value for the entire city was 81.0dB. Median LAeq value for peak traffic hours was 81.1dB and for off-peak traffic hours 80.4dB. Median values for L10, L50 and L90 for the city were 83.1dB, 76.6dB and 71.9dB respectively. CONCLUSIONS: Environmental noise levels in Colombo city are well above (13.3dB to 21.0dB) the levels recommended in the National Environmental (Noise pollution) Act of Sri Lanka.