Noise pollution or excessive noise can be described as any kind of unwanted sounds, which have an adverse effect on human beings, animals and plants. The noise generated during heavy traffic is a primary example for it. Increase in population and development leads to a corresponding increase in traffic, machinery and equipment with the result that the noise pollution starts to grow. Excessive noise leads to even loss of hearing.
In fact, noise pollution is an integral part of the industrial environment. It is rising along with the fast pace of urbanization. Even in non-industrial areas, noise is born due to activities such as printing-dyeing machines, repair of cars, grinding, etc in the surrounding environment. This noise not only produces irritating sounds, it also drains the blood flow to the heart. Constant noise levels leads to increase of cholesterol in the blood, which constricts blood vessels, thus increasing the chance of heart disease. Health experts believe that increased noise gives rise to neurological disease, nervous breakdown, etc.
What is normal hearing level?
The transmission of noise is through the air. Sound intensity measuring unit is set in terms of decibels hearing level (dBHL). Experts say that more than 100 decibels of sound badly affects our hearing power. According to the World Health Organization (WHO), 45 decibels of sound is considered ideal for cities. But in large cities of India, sound measurement levels are generally more than 90 decibels. Mumbai is the world’s third most noisy city. Delhi is right behind it.
Adverse Effects of Noise Pollution
Rising levels of noise in Indian cities has been affecting people’s hearing capability, which is deeply disturbing as the ability to hear sounds is closely linked to mental development. It is because the development of vocal skills is dependent on normal hearing. Of late, the problem of deafening noise pollution is on the increase worldwide.
Prolonged exposure to noise results in several adverse effects – sleep disturbance, irritability, stress, tension, distraction, risk of heart disease, influence on quality of life, interference with communication, health and well-being outcomes, behavioural and mental health effects and diminished performance.
Noise Pollution – a Health Hazard
Noise has negative consequences on human health and behaviour. Unwanted sounds can damage physiological and psychological health. Noise pollution leads to annoyance, aggression, hypertension, high stress levels, hearing loss, tinnitus (the hearing of sound when no external sound is present), sleep disturbances, and other harmful effects. Stress and hypertension are major health problems, whereas tinnitus can cause memory loss, severe depression and at times fits of perplexity.
Noise Pollution and Hearing Loss
Hearing sensitivity reduces with time and by the age of 79, it becomes difficult to detect whether the difficulty in hearing is noise induced or due to age but the constant exposure to noise may lead to noise-induced hearing loss even in the young people. Greater decline in hearing sensitivity is reported in people exposed to noise than those living away from noisy environment.
Based on various experiments, it has been shown that when the intensity of the sound exceeds 90 dB, it leads to hearing impairment of varying degrees. Hearing impairment is based on various factors, notable among them being noise-induced as there is a limit to individual sensitivity to withstand noise.
In a study conducted in Lucknow to study the effects of increasing noise pollution on the people exposed to noise for more than 10 hours for five consecutive years, it was shown that 55 percent of people living in the city suffered decline in their auditory ability.
Other Noise-induced diseases
The high level of noise pollution cause several types of behavioural changes in humans. Exposure to long-term noise pollution may result in neurotic mental disorder, stress and strain in the muscles and excitement in the nerves. Noise pollution also leads to annoyance and general lack of enthusiasm in life and profession.
High levels of noise can give rise to cardiovascular diseases. Exposure to noisy environment can lead to increase in blood pressure by five to ten times with stress levels rising manifold. All these factors cause hypertension as well as coronary artery disease. Due to unbearable noise, man may develop various maladies and diseases, anxiety, heart disease, stretched eye balls, strained muscles, mental stress, digestive system disorder such as stomach ulcers and intestinal diseases.
Findings on Noise Pollution
Explosions and sonic boom (noise travelling at more than the speed of sound, generated by jet aircraft) can cause abortion in pregnant women, and distortions in newborn babies of women living under constant noise.
In a study, it was found that construction workers suffer from hearing deficiencies caused by noise, which is one of the most important occupational diseases. Hearing disorders affect the workers’ fitness for work in several ways. Hearing difficulty, tinnitus, auditory disorders as fallout of noise induced hearing loss (NIHL) have become common problems throughout the construction industry. The workers are unable to cope with their exposure to noise due to the frequent use of noisy machinery, such as mechanical saws, compressors, grinding machines, drills, and other cutting tools, etc.
Noise Pollution: A Threat to Environment
Noisy areas may cause reduction in the usable habitat of animal life, which can ultimately lead to extinction of the entire species. One of the best known cases of damage caused by noise pollution is the death of certain species of marine whale (beached whale) when they were pushed to the sea shore by the loud sound of military guns.
Scientists and researchers have conducted experiments which show that there is change of intensity in animal vocalizations in response to environmental noise. One such experiment known as the Lombard vocal response establishes that noise makes species communicate louder, as there is a natural and repeatable response of the vocal system to variations in noise level. When one species begins speaking louder, the second species imitates the sound so much so that the entire ecosystem automatically resonates with sharp ringing sounds. The voice of other species gets masked by anthropogenic sounds such as caused by ships, sonar and marine seismic surveys, which leave a disturbing effect on marine life.
The threat of noise pollution needs to be taken seriously. For this, the first step is to make people aware with various diseases caused by noise pollution. We should focus on using low noise emitting machines and equipment. High-sound producing machines must be placed in sound-proof buildings and the staff handling such machines should use sound absorber ear plugs. Industries and factories must be installed far from cities or habitat. We should give up our habit of honking too frequently. More and more trees should be planted along the roads as they help in reducing noise pollution by serving as sound absorbers.