Incessant toot of horns. Revving of motors. Raucous blaring of loud speakers. Copious chant by religious sects. The clack and bang at construction sites. Whirring power generators... Yes, we are talking of the ubiquitous 'noise-pollution'. Heaven help those dwelling in the vicinity of airports, railway tracks, factories and arterial highways!
As if these cacophonies aren't enough, there's further auditory assault from gadgets like iPods. Not to mention other aural entertainment sources such as stereos, music systems, etc, which are cranked up till the eardrums get a thorough battering!
According to WHO, the 'sustained exposure' to sound levels higher than 80 dB can cause irrevocable damage to human hearing faculty. (dB/decibel is the unit for measuring the intensity of sound levels). It's indeed alarming to know many busy roads in Bangalore, roars at 90-100 dB, as against prescribed safe limit of 65 dB. With over 19 lakh vehicles plying regularly on our roads, including 14 lakh two-wheelers, 2 lakh cars, 76,000 autos and 10,000 buses, the hearing of regular long-distance commuters is indeed at stake. More staggering is the startling find that virtually one-fourth of the City's traffic cops are suffering from varied degrees of hearing loss, owing to escalating vehicular noise pollution. Well, how does this happen?
The inner ear has teeny hair rows that move in response to vibrations. This movement generates electrical signals, which are transmitted to the brain through auditory nerves. Actually, these inner ear hair cells are the primary sensory cells that produce action potential in the auditory nerves, sparking nerve impulses. These cells are also responsible for fine auditory discrimination. Different sounds move hair bundles in different ways, allowing the brain to distinguish them. Exposure to prolonged loud sounds damages both the sensitive hair cells and the auditory nerve fibre. Since these hair cells do not regenerate, the loss is irreversible.
According to an US-based doctor, William Stewart, high-level noise is a major contributor to many diseases. It can cause/exacerbate migraines, digestive/ respiratory disorders, ulcers, et al. During waking hours, if sounds over 70 dB can trigger off adverse automatic reactions; while in slumber, noises no higher than 55 dB can set off an alarm. Offshoot of which, the nervous system responds by tensing the muscles, accelerating heartbeats, increasing fluid secretion in intestines. Noise studies have also shown great nexus between BP levels and noisy environs.
It's appalling to know, many, in the age group of 25-40, are striding into 'hearing care' clinics today with ailments such as 'tinnitus' (hearing of ringing sounds, even in the absence of background sounds), hearing of 'muffled voices' in normal conversations, etc, etc. That's because, apart from the burgeoning vehicular din, we're constantly rocked by umpteen noise-fraught entertainments too. Anju Aggarwal, a leading advocate explains, "Noise can insidiously damage one's physiology like slow poison. Chronic noises can even lead to congenital defects in unborn babies. They can even cause damage to property by creating chinks on building walls."
Downright irksome
Well, if these high frequency noises can have deleterious impact on human bodies, there are some noises that can be downright irksome, especially when you're wrapped up with an important work. Like sounds of chiming phones, whining ACs, dripping faucets, ticking wall-clocks, baying dogs, jangling sound of printers, clattering sound on keyboards, nettling sound of footfalls, tinny thrum of music on others' mobiles, even spouse's snoring, or rattling of windbag colleague in strident, guttural tones!
Remember, some of these noises can sublimally engender aggression, disrupt concentration, hinder communication, thwart efficiency/productivity, ignite stress/tetchy behaviour, impede learning process, even can give you sleepless nights. Well, what's the panacea then, to drown out deluge of these despicable noises?
For one, the use of 'hearing-protection devices' like earplugs/earmuffs is a good bet while you're in a loud or annoying sound zone. Nowadays there are specially designed ear plugs available. These ear-protectors can be used while studying/working in noisy zones, while riding/travelling, lighting high-sounding crackers, watching films in multiplexes, while in amplified rock-concerts (here, the sound output touches a shocking 120dB!), or even while listening to hollers of a stentorian-voiced boss! Since it filters only 40% sound frequencies, you can still hear the ambient sounds, at relatively lower levels. If these earplugs are rightly fitted, they do work out well.
(For more details on earplugs, contact ravinarayan@dbsafe.com)
