‘Noise control: Make the right design choices'

Ashwini Phadnis | Updated on July 30, 2011

Dr M. L. Munjal, Professor, Indian Institute of Science, Bangalore

As the debate on aircraft noise affecting people staying close to airports gathers momentum in India, Dr M. L. Munjal, Professor, Indian Institute of Science, Bangalore, and head of the National Committee on Noise Pollution Control, outlines the various issues involved.

Excerpts from the interview:

Of late, there has been a lot of talk about airports and how the noise of the aircraft is causing a lot of discomfort to residents nearby. What is the reason for this sudden interest in airport noise?

Airport noise is something that we have been taking for granted. One reason for this is that all the airports were sufficiently away from living areas. It is just that cities have been growing and getting closer to the airports.

An airport cannot be physically shifted, but we could have taken precautions to see that the living communities did not get too close to the airport. Near an airport, there is a funnel at about a 30-degree angle, where noise is at the maximum on both sides. These could be marked on a city's master-plan, such as, say, the Delhi Development Authority master plan.

Is this being done right now?

No, it is not. And even where it is done, it is not shared with the public. The apprehension is that if they declare this, then the property value will come down and therefore it is in everyone's vested interests to not talk about it.

Both sellers as well as buyers are involved in this. All of us are party to it. To say that the Airports Authority is to blame or DIAL is to blame is really deviating from the truth.

You mentioned Bangalore?

I can see what is happening in Bangalore now. The airport has been shifted. It used to be in the centre of the city. Now, it has been shifted 35 km away and look at the cost we are paying for it — so much extra fuel, extra time and air pollution.

All this is happening at a cost but even then the advantage is being frittered away because the city is expanding and localities are getting closer to the airport again. All the property values have gone up in that area because everyone wants to be as near the airport as possible. No one is worried about the noise. That seems to be the last concern.

Noise has always been a late comer to the scene, even in industry. First, you do everything you want to do — make the machines, make the layouts, do everything and then say: “Oh my God, noise!”

Noise should be taken care of right at the planning stage. Designing for quietness is the most cost-effective way of finding a solution. It costs you very little. I am saying this because I was a consultant with a premier car manufacturer. We were able to design a vehicle, which, within six months of the first prototype, satisfied international standards of noise. It did not cost much because we made the right choices in the design.

Right choices such as what?

That will require too many technical details. But what I am saying is that the engine you choose, the speed you choose, the configuration of the engine you choose, and how it is mounted and the floor of the vehicle, all make a difference.

When you make the right choices it does not cost you anything, or if it does, it costs very little.

But once a vehicle is given to you and then you say please do something, then that something turns out to be very costly, because something will have to be undone, and something new will have to be added, some costs will have to be borne. So, retrofitting is never the right solution.

Have the right choices not been made for airport noise?

In the case of airport noise control, the whole thing is a retrofit. All of us have to sit together and bear the cost. And cost does not necessarily imply money, it could also be discomfort.

Isn't airport noise something that happens globally?

Every country has gone through these problems but they started in, say, the 1960s or 1970s. So, now we have an advantage of what they learnt from their experience. Let us not make those mistakes.

How are you trying to create awareness about noise in society?

This is being done in many ways. Through radio, television, cartoons. Look at fire-crackers. Delhi took a lead on that because the teachers started talking to children, telling them that the crackers they were using and enjoying were being made by other children who were losing their childhood. They were paying a price for it. That appealed to every child.

Now you see that instead of parents telling children not to use crackers, it is the children who are telling their parents not to buy crackers.

Another thing I have been telling people is how much they are harming themselves at discotheques. They are subjecting themselves to 125 decibels; it is like a truck without a muffler. That is the kind of noise they subject themselves to, in the name of music.

Noise has been recognised as a slow poison that teenagers subject themselves to, and by the time they realise its harm, it is much too late.

Published on July 26, 2011

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