Noise Level inside Sri Lanka Transport Board Buses and Hearing Impairment of Long- and Short-Distance Bus Drivers of Ampara and Batticaloa Districts, Sri Lanka

BACKGROUND: Transport drivers are more vulnerable to hearing impairment due to the traffic environment and fast-growing urbanization. OBJECTIVE: The study aims to determine the noise level inside the Sri Lanka Transport Board (SLTB) buses, hearing impairment of state transport bus drivers, and its associated factors in the selected districts of Eastern Province, Sri Lanka. MATERIALS AND METHODS: A cross-sectional descriptive study was carried out among 256 state bus drivers using a systematic sampling technique. A screening tool to assess the level of hearing impairment of drivers and a format to measure equivalent noise level inside the SLTB buses were used to collect data. Noise measurement was done using Benetech Sound Level Meter (Model DB 130). RESULTS: With reference to the noise level inside buses, 88.4% (n = 53) exceeded 85 dB (A), and 21.7% of buses (n = 13) were above 90 dB (A). According to the hearing tool's hearing impairment assessment, the hearing of the majority of the study participants (84.4%, n = 216) was not affected. The association between hearing impairment and past history of ear diseases, surgeries, or head trauma was statistically significant (P = 0.017). CONCLUSIONS: Noise level inside the SLTB buses in Ampara and Batticaloa districts exceeded the 85 dB limit prescribed under the WHO standards of occupational noise exposure. The years of service of a bus was the only factor shown a statistically significant association with the level of noise inside the bus.