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Noise - The Silent Killer: Noise Pollution & Urban Health

Noise is an invisible and often disregarded form of pollution, yet its effects on urban health are quite alarming. After a while living in a busy city, we tend to get accustomed to the blaring sounds of sirens, impatient taxis, drilling and clanking in nearby construction sites, it becomes background noise - dimming the underlying harmful impact on their health. The World Health Organisation (WHO) has called out the threat of noise pollution on health, that cause hearing loss, cognitive disorders, hearing loss, stress and depression Here we explore, the effects of noise on human health and what can be done by policymakers.
Author: Siphilele Magagula
Image: Courtesy of Courtesy of Hindustan Times
How Noise Is Pollution A ‘Silent Killer’?
Some experts ironically refer to noise as a ‘silent killer, affecting both physical and mental health’. Although noise is recognized as a major environmental stressor, there is a lack of sufficient research on its association to mental health. The Gutenberg Health Study (GHS) carried out an investigation on 15,000 people aged 35 to 74 to assess the noise annoyance from traffic, industrials sites, aircrafts, railways and neighbourhoods (during the day and during sleep hours). Results found that depression and anxiety increased with the degree of overall noise annoyance, with aircrafts leading - affecting 60% of the participants. Strong noise annoyance was linked with higher prevalence of depression and anxiety, while severe annoyance has been linked with reduced well-being and health.

Image courtesy of Igor Ovsyannykov via Stocksnap
Coronary Heart Disease (CHD) has also been associated with noise pollution. According to India’s Central Pollution Control Board CPCB report (2016) high noise levels can contribute to cardiovascular effects, while exposure to moderately high levels can cause a rise in blood pressure.
New research found that long-term exposure to traffic noise may account for approximately 210,000 deaths in Europe each year. A 2007 issue of Science of the Total Environment found an 80% increased risk of cardiovascular mortality for women with a sensitivity to noise - revealing noise sensitivity as a serious factor in cardiovascular mortality in women.
Child development is also greatly affected, as expressed by Dr. Eoin King - assistant professor of acoustics and author of the book Environmental Noise Pollution: “Studies considering the effect that noise may have on children have found that tasks such as reading, attention span, problem-solving and memory appear to be most affected by exposure to noise.”
With all this evidence, noise pollution’s impacts remain unreported and underestimated.
How Loud Is Too Loud? - The Road to Noise Regulation

Image courtesy of Louis Lo via Stocksnap
According to the World Health Organisation’s Make Listening Safe Guide 85 decibels (car noise - 70 decibels, a plane taking off - 120, a jackhammer - 100) is the highest safe exposure level for a period of 8 hours. How many decibels does your city record? Here is a list of the world’s noisiest city to live (in no particular order), see if yours makes the cut:
Karachi, Pakistan - 15 million inhabitants - traffic noise recording a screeching 90 decibels
Shanghai, China - Population of 24 million. 85 decibels or higher.
Buenos Aires, Argentina - 3 million inhabitants - 85 decibels.
Madrid, Spain - 3.2 million inhabitants - 55 decibels every night until the early hours of the morning and 65 decibels during the day.
Tokyo, Japan - 35 million inhabitants - 90 decibels.
Delhi, India - 21.75 million inhabitants - 82.5 decibels on a regular basis.
New York, New York - 8 million residents and a staggering 50 million tourists per year - 70 to 90 decibels and beyond. Cairo, Egypt - 9.5 million inhabitants. The noise levels reach 90 decibels as early as 7:30am.
Kolkata, India - 5 million inhabitants - 100 decibel noise levels.
Mumbai, India - 13 million inhabitants - It’s the noisiest city in the world with noises levels that exceed 100 decibels!

India | Image courtesy of Jay Bergesen via Flickr
What Can Policy Makers do?
“The most effective way to control noise is at the source. If we could make planes, trains and cars quieter we would solve a lot of our problems,” says Dr. Eoin King...going to the source of the noise will produce longer lasting solutions. Using a multidisciplinary approach to tackling ways to reduce the noise levels of the main sources of noise pollution will largely influence the rates of noise and air pollution, therefore lowering premature deaths - greatly improving urban health and wellbeing.
Integrate Design Solutions Collecting more data
To target noise pollution in cities and adjust policies, planners and policy makers can integrate smart technologies to collect data such as the NoiseTub app. Developed by researchers at the Free University of Brussels in Belgium, this app collects data on city noise levels by enabling users to record the location and times when decibel levels are highest, producing a detailed “noise map” of the city. This technology equips planners and policy makers with information they can use to target noise pollution more effectively.

NoiseTube | Image courtesy huffingpost.fr
Reduce Car Usage: Banning, Prevention And Alternatives
Mumbai, which is considered the noisiest city in the world due to traffic, has targeted its motorists in an attempt to lower their record 110 decibel noise levels. Since 2016 these levels are reportedly improving due to bans on honking and governmental measures such as fines. In addition, in 2017 the regional transport offices of the Maharashtra Motor Vehicle Department (MMVD) started a 15-day drive as a campaign to raise awareness on the dangers of noise pollution.
In 2015 Paris also cracked down on its noise pollution and implemented a car-free day - a car ban applied to 30 percent of the capital city which led to a dramatic drop in both air and noise pollution. This encouraged the mayor’s office to plan more vehicle-free days which would improve not only noise levels but air quality.
Although these are commendable efforts, limiting car traffic should be also be combined with promoting alternative methods of transportation such as light rail systems, electric cars and buses, which produce less pollutants. Reducing speed limits could also greatly improve the rate of noise in busy city centers.
Integrating Trees As Sound Barriers
Planting more trees and greenery in cities has been proven to improve air quality as well as mental health. It is also an efficient way to combat noise pollution in busy cities, as trees absorb sound and can create buffer zones between roads and residential areas.
Revisiting Urban Planning & Industrial Policy
In India the urban development authority of every city make efforts to delineate noisy polluted industrial areas from residential areas, however, deviations from the master plan are rampant across the country. This results in industrial facilities being built in residential areas, disturbing the peace of unassuming residents. In order to spark change, community effort will be necessary to encourage policy makers to follow the master plan. Sound insulation in industrial buildings located in residential areas may be an alternative solution.