No horn, please: How street noise is hurting our health
Dust mixed with toxic fumes from vehicular exhausts exacerbate lung and heart diseases and trigger death from heart attack, stroke, chronic obstructive pulmonary disease, lung infections like pneumonia, and cancers of the lung and respiratory tract.
What is less known is that traffic noise adds to this incessant vehicular assault on human health. Revving motors, ceaseless honking, overloaded vehicles and blaring music not just damage the health of commuters but also those who live or work around busy roads.
Annoyance, irritability and hearing damage are the obvious fallouts, but several studies show that traffic noise leads to high blood pressure, heart disease, stroke, heart failure, diabetes, depression, memory impairment, disrupted sleep and hyperactivity in children.
With the time spent commuting growing by the day in noisy cities, both big and small, even those who do not live close to busy roads risk sacrificing more than just sleep.
Environmental noise from traffic and aircraft disrupts the body on the cellular level to raise heart disease risk factors, according to a review of the underlying mechanisms that lead to noise-induced heart disease. Sound pollution causes metabolic abnormalities and autonomic imbalance, which is characterised by dizziness and exercise intolerance, said the study.
Noise activates the sympathetic nervous system to induce a stress response, which raises the blood levels of the stress hormones such as cortisol, adrenaline and noradrenalin, even during sleep. These hormones prepare the body to survive an imminent “fight for flight” threat by making the heart beat faster, constricting blood vessels and pushing up blood pressure to feed more blood to the brain and muscles. When this physiological stress becomes constant, it leads to heart disease and diabetes, among others.
Traffic noise harm children’s ability to learn as they are more affected than adults by noise while doing tasks involving speech perception and listening comprehension. It also affects learning that doesn’t involve speech perception and listening comprehension, such as short-term memory, reading and writing. This, over time, affects their cognitive development. Another study in Teheran found it affected the auditory verbal learning and memory of boys more than girls.
Exposure to traffic noise also causes behavioural problems, particularly hyperactivity and inattention symptoms, in early childhood. Sleeping in rooms exposed to sound of night-time traffic raises children’s blood pressure, raising their risk of heart disease in later life.
Night-time traffic noise lowers the quantity of sleep, leading to irritability, lowered attention, delayed response, tiredness and fatigue. People who live near busy streets have difficulty falling asleep, wake up frequently during the night, and get up too early, found a population-based study from Norway, where traffic movement is quieter than on India’s roads.
People living in areas with high traffic noise were 25 percent more likely than those in quieter neighbourhoods to have symptoms of depression such as sadness, loneliness and trouble concentrating. In developing countries such as India where traffic movement is often more chaotic, mounting stress and irritability fuels hostility and road rage.
No horn, please
Noise hazards can be mitigated by improving traffic management and regulating driving behaviour, which should include both motor and non-motor road transportation. According to Section 190 (2) of the Central Motor Vehicles Act (2), “Any person who drives or causes or allows to be driven, in any public place a motor vehicle, which violates the standards prescribed in relation to road safety, control of noise and air pollution, shall be punishable for the first offence with a fine of ₹1,000 and for any second or subsequent offence with a fine of ₹2,000.”
Along with fines, the challenge is to make aggressive road warriors aware that noisy driving harms their own health as much as others.