Thursday, April 11, 2019

Noise pollution ..

Effects of noise pollution (click here..)

Note of Noise pollution click here

I am reminded of my Engg college days in Trivandrum, Kerala when we had to carry out the final year project. It was on identifying the noise pollution levels in the city of Trivandrum, to plot a noise contour map. While my friends were busy carrying out great projects on rocketry and other things in VSSC . , I took it as a great challenge to do this project for the society. We went around the important traffic points in the city of Trivandrum on week days and weekends at different times of the day to find the sound levels to plot the sound map of the city of Trivandrum. We succeeded finally in doing that. That was my first experience with the environment. We got the Sound Level Meter from the CSIR Lab in Trivandrum. 

Nowadays I have asked my student to download many of the sound level meters, especially one from Google , properly calibrated. 

Sound levels are measured in decibels(dB). It is a unit for expressing the relative intensity of sound on a scale from 0 to 130.

Normal conversation is about 60 dB, a lawn mower is about 90 dB, and a loud rock concert is about 120 dB. In general, sounds above 85 are harmful, depending on how long and how often you are exposed to them and whether you wear hearing protection, such as earplugs or earmuffs.

Headphones : Standard headphones, when turned all the way up, can emit sound as loud as 110 decibels, the equivalent of strapping a power saw to each ear. Many people have no idea how much damage they are doing to their ears when they listen to music at a high volume for an extended period of time.

Noise level of 80 decibels or more for more than 8 hours a day increases tension and changes in breathing patterns. Continued exposure to high levels of noise results in fatigue, hearing loss or even total loss of hearing, changes in blood circulation, changes in breathing, etc.

Types Of Noise Pollution:

The types of noise pollution are categorized into three broadly.
1. Industrial pollution
2. Transport noise
3. Neighborhood noise. 
1. Industrial Noise:Industrial noise is caused by some high intensity decibels that is the result of industry machines and other such appliances. The noise comes from the use of mills, heavy industrial machines and even the small exhaust fans that run for a long period. Noise from mechanical saws and pneumatic drills is unbearable and the ultimate form of pollution to the public and neighborhood. This is one cause of noise pollution. 
2. Transport Noise:Transport noise is simply inevitable. The traffic jams cause considerable amount of vehicle noise and the honking of the many vehicles in the crowd are nothing but a pure nuisance. Whether road, rail or aircraft, their noise is a considerable contributor to noise pollution. Tractors and other heavy vehicle sounds are difficult to control for their sound. 
3. Neighborhood Noise:Gadgets, electrical appliances like the grinder and mixer are the prime contributors to noise pollution. Loud loudspeakers in the name of wedding, political parties and other such events call for a significant amount of noise pollution. In the long run, they become difficult to bear posing problems to the health of humans.
150 decibels is usually considered enough to burst your eardrums, but the threshold for death is usually pegged at around 185-200 dB. A passenger car driving by at 25 feet is about 60 dB, being next to a jackhammer or lawn mower is around 100 dB, a nearby chainsaw is 120 dB.

Around airports, you have noise levels around 120 dB at the time of takeoff.

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