The Adverse Effect of Occupational Noise and Lack of Awareness about Noise Induced Hearing Loss (NIHL) Among Traffic Police

Author: By Himanshu Kumar Sanju and Prawin Kumar, Ph.D.

Noise exposure can cause adverse effects on our auditory system as well as non-auditory effects such as depression, fatigue and the inability to concentrate, as reported by previous researchers. For these reasons many governments around the world have devised regulations limiting a worker's exposure to noise, and mandated the use of hearing protection devices, if noise exceeds a permissible level. Traffic police are among the most targeted populations to experience the effects of noise exposure. For decades, the United States, as well as other economically advantaged countries, has relied on scientifically-defensible guidelines, designed to prevent noise induced hearing loss (NIHL) for police exposed to high levels of noise. In developing countries, however, a lack of awareness about proper use of horns, permissible noise levels, uses of hearing protection devices (HPDs) and the adverse effects of occupational noise have posed threats to traffic police. Further, even in developing countries with a keen awareness of these adverse effects, governments may lack the authority to measure noise levels and require the use of hearing protection when noise levels exceed a predetermined level. This article will review various studies which demonstrate adverse effects of occupational noise, lack of awareness about NIHL and uses of hearing protection devicess among traffic police in developing countries. Data show that there is a need to educate traffic police about hazardous effects of noise exposure and the importance of hearing protection devices. Further, identified persons at risk should be referred for a detailed audiological evaluation by a qualified audiologist.

It’s a known fact that noise exposure for long durations can cause noise induced hearing loss (NIHL). Short durations of noise exposure due to a blast or impulse can cause a hearing impairment, which is known as acoustic trauma. Acoustic trauma can result in mixed or sensorineural hearing impairment, whereas NIHL mainly results in sensorineural hearing loss.1

The adverse effect of noise exposure is well reported by researchers and includes both auditory as well as non-auditory effects such depression, fatigue, impulsive behavior, and the inability to concentrate on tasks.2,3 It can also cause temporary or permanent shifts in threshold due to noise exposure for longer durations. In developing countries, rapid growth of cities and towns has increased the use and ownership of motor vehicles.4 Lack of awareness among the public about the proper use of horns also contributes to noise pollution.5 Traffic police who are engaged in controlling heavy traffic are more susceptible to NIHL, as they are continuously exposed to the high level of noise.6 In developing countries like India, the permissible occupational noise levels limit, for 8 hours’ time-weighted average, is 90 dB.7 A survey done at the city of Hyderabad in 2010, illustrated the effects of noise pollution on traffic police. Results showed that 76% of traffic police were exposed to high level of noise. The survey also reported that those traffic police who had worked for five years continuously, during their service period, reported a 100% incidence of hearing loss.8

A study conducted by Mishra9 on traffic police within the Indian population, reported high levels of noise exposure among traffic police, ranging from 75 to 80dB at different traffic points, and reaching a maximum sound level of 103dB, which is threat for traffic police. Shrestha et al., 10 in Nepal also reported traffic police personnel are at constant risk of NIHL. Further, a study conducted by Gupta et al.11 showed that a large number of traffic police were oblivious to the adverse effect of occupational noise and they did not consider it as an occupational hazard. Gupta et al.11 also noticed that even though only 5.5% of the traffic police rated their hearing ability as below average, a larger percentage of subjects reported having trouble during normal (40%) and telephonic conversation (16.7%). Tripathi and Tiwari12 also confirmed that while only 2.3% of traffic police felt that their hearing ability was below average, 11.6% of traffic police complained of regular tinnitus. By contrast, only 6.1% is the prevalence of tinnitus in normal population.13 Similarly, Vekatappa et al.6 also reported that only 3.33% of traffic police rated their hearing ability below average but 25% of the participants reported missing some conversation over the telephone. Further, 16.6% of participants suffered from tinnitus. All of the above studies showed that, although the self-assessed prevalence of hearing loss was found in a lower percentage of subjects, closer scrutiny of the supplementary questions to assess the hearing status showed that a large proportion of participants do have a hearing impairment—even if the hearing impairment may not be found to disturb day-to-day conversation.

Venkatappa et al.6 reported that 100% of the traffic police had never used any ear protection devices. A lack of available ear protection devices was the reason for this in all cases of non-use in the report. Similar findings were also reported by Gupta et al.11 where 100% of the traffic police had never used any ear protection devices and 64.4% of the traffic police were unaware of the harmful effects of noise. Contrary to the above finding, Tripathi and Tiwari12 reported that only 4.6% of the traffic police used ear protection devices and 67.4% of traffic police did not use any method to reduce exposure to noise. Remaining respondents reported using their fingers, hands and/or cotton to avoid noise exposure.

Omidvari and Nouri14 reported that noise pollution has adverse effects on behavioral conditions. Agrawal and Swami15 reported 60-85% people in the study described that vehicular road traffic was major source of noise pollution and that it creates annoyance among people. About 52% of the sample population reported frequent irritation, while 67% people reported suffering due to a common noise-related problem like headache or loss of sleep. A study by Berivan, on industrial workers, showed 81.11% of the workers were annoyed from noise in their workplace. They also reported a relationship between duration of employment year and feelings of annoyance. Their findings were statistically significant. Physiological and psychological effects of noise (i.e. headache, nervousness, stress, speech interference and insomnia) were reported to be significant in these individuals.16

The negative consequences of noise exposure are well cited in the pertinent literature. This review also illustrates the lack of awareness and poor knowledge among traffic police about the importance of using hearing protection devices (HPDs) and the adverse effects associated with occupational noise. Hence, there is a need to educate traffic police about the hazardous effects of noise exposure and the importance of consistently wearing HPDs. Further, persons at risk for developing NIHL should be referred for an audiological evaluation to rule out involvement of the peripheral and central auditory system. The present review also revealed noise-related annoyances and hazards among traffic police, beyond hearing loss, and provides a sound rationale for educating police to minimize the health-related risks due to noise exposure. Prevention is the best cure.    
Himanshu Kumar Sanju has Graduate and Post-Graduate degrees in Audiology and is presently working as an Audiologist Grade 1 at the All India Institute of Speech and Hearing, Mysore-6, Karnataka, India. His areas of interest include: Cochlear Implants, Auditory Evoked Potentials, NIHL, Psychoacoustics and Hearing Aids.

Dr. Prawin Kumar, Ph.D. is a Lecturer of Audiology at the All India Institute of Speech and Hearing, Mysore-6, Karnataka, India. Dr. Prawin has published many original research papers in National and International journals. He has also attended seminars and conferences at both National and International levels. He is a reviewer of National and International Journals. He is also the esteemed EC member of Indian Speech and Hearing Association (ISHA). His areas of interest include: CAPD, Auditory Evoked Potentials, Psychoacoustics, Implantable Devices of Hearing Impaired, Hearing Aids and Speech perception.
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