By Dr Valton, ENT Specialist CMI – HCMC
The effects of noise pollution on our health are numerous; our hearing is considered to be at risk when exposing from 80 decibels during an 8-hour workday. If this level is higher (above 120 decibels), even for a short time exposure duration, it could be dangerous and lead to deafness, an irreversible phenomenon. Deafness can be recognized as an occupational disease. Noise causes fatigue and stress and acts on the nervous, cardiovascular and digestive systems. But, it does not only affect our health, but it can also harm the quality of our work by disturbing our concentration and be the cause of accidents at work.
In a city like Ho Chi Minh, there are many sources of noise pollution; Early in the morning, we are awake by the singing of a rooster or the barking of a neighbor’s dog: a new day begins…But noise can be “voluntary” when we choose to go in a café or a night club, where there are no upper limit prohibitions, in night clubs, the stronger the noise is, the crowded the place is, better it is..
With children and teenagers, music is always there with headphones directly in contact with their ears. Fortunately, legislation now requires smartphone manufacturers to indicate the intensity that could be harmful to them. “Involuntary” noise is, particularly, here in HCMC, a nuisance. Traffic with motorbikes having a nonstandard engine and exhaust, officers, who have no authority over drivers, using their whistles at all times without much efficiency on the traffic, but so harmful to our ears, motorbikes’, horn used for no apparent reason, shops playing more and more loud music to attract more customers… There is also a noise seen as “voluntary” because imposed by our living conditions; the noise produced by the air conditioning and fans that we use almost permanently.
The first and most important affected function by being exposed to excessive noise levels is the sleep. Sleep disturbances occur from 30 dB. The hearing is on standby, but our ears have no “ear lids” to protect them, so noises can affect the sleep quality making it hard to fall in sleep, can also wake us earlier without being able to fall again asleep. Early in the morning, noises easily wake a sleeper and prevent him from getting back to sleep; it can also modify our sleep stages. Such sleep deprivation leads to excessive chronic fatigue and drowsiness, reducing work motivation, decreasing performances adding chronic anxiety and sleep disturbances which are sources of vigilance during the day and which may increase risks of accidents.
Noise can affect communication; noise from 45 dB compromises the understanding of speech. Vulnerable people and those with hearing loss, elderly people and children in the process of learning and reading language can be the victims of those interferences making comprehension difficult or impossible. Above 65-70 dB there can be psycho-physiological effects after prolonged exposure, sensitive people can develop permanent disorders, such as hypertension and ischemic heart disease.
There are contextual factors of tolerance: chosen noises are less annoying than any other noises; a predictable noise is less annoying than an unpredictable one, and cultural factors, climate, for example, can modify the tolerance. Apart from discomfort, others important effects can change the attitude, and social behavior, and bring an aggressive attitude and behavioral disorders, less sensitivity, and interest to others, etc.
Hearing Loss due to Noise at 80 dB (A)
Environmental noises do not reach intensities that are directly damaging our hearing. On the other hand noise at work on prolonged time, listening to loud music and the practice of leisure activities such as shooting or motorized recreational activities, expose people to risks of severe hearing impairment. Hearing impairment is defined as a diminution of the hearing threshold. Hearing impairment can come with tinnitus (buzzing or whistling). Across the globe, hearing loss due to noise is the most widespread hazard. About children, taking into account their habit of playing with noisy toys, be aware that the maximum sound pressure should never exceed 80dB and for a short duration of time. The main consequence of hearing loss is the inability to understand speech under normal conditions, and this is considered a severe social disability.
In conclusion, it ‘s hard to avoid noise in a city like Ho Chi Minh even though some districts are somewhat more spared than others. When going to a club, avoid getting too close to the speakers, the same thing should be done in coffee’s shops and bars. Fortunately, the brain gets accustomed to noises made by air conditioning and fans, and these do therefore not modify the quality of sleep. As for traffic I have really no idea how to protect us from the noise! Wearing protective earmuffs or earplugs can be a solution, but for people using motorbikes, these tips could be dangerous because of traffic, which in Saigon, due to its intensity, demands particular vigilance considering the way people drives.
You should, therefore, be aware of the potential risk of noise related to hearing problems and take, always, the preventive measures to avoid them.