1. Fighting Delhi Smog
By:
D K Singhal
deveshksinghal@gmail.com
Fighting Delhi Smog

2. Delhi Smog
We all know smog!
We know from where the smog comes.We know from where the smog comes.
We know what are the ill-effects of smog.
We know what should be done to get rid of smog.
Still, we are tolerating smog.
Still, we are suffering from smog.
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Still, we are suffering from smog.
Why?

3. Who’s Responsible?
While discussing smog, we often debate on who is really
responsible for smog.
A simple approach is to identify the source, find out the
culprit and take necessary actions to reduce it at source.
At least for 80% of smog particles, we know who are
responsible, but taking action against the guilty ones is not
that easy. However, we must trust that our Government is
seriously taking necessary actions, which might take some
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seriously taking necessary actions, which might take some
time to materialize.
Anyway, we are suffering today!

4. Fighting Smog
The next approach is to fight smog.
The commonly used and most talked actions include artificialThe commonly used and most talked actions include artificial
rain, spraying water using a helicopter, spraying water on
trees, initiate controls to reduce vehicle emission, initiate
controls to reduce industrial pollution, restrict construction
activities.
However, the question appears, why most of the efforts are
not as successful as natural rain?
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not as successful as natural rain?

5. Natural Rain
After every rain, have you noticed that the particulate matter
concentration decreases drastically.
The water‘washes’ the air, and the particulates are washed
away.
Probably the concept of spraying water from helicopter
popped up from the above.
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6. Rain isn’t that Efficient
Rain, while highly efficient in reducing smog, is itself not that
efficient in the topic concerned.
Imagine the quantity of water required to bring particulates
level to acceptable level.
Artificial rain using helicopter, cloud seeding etc. cannot be
used effectively for such large cities.
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Shouldn’t we think of controlled rain?

7. Do We Know Rain?
When we talk of rain as an efficient tool to bring particulates
down to get rid of smog, it becomes necessary to study rain.
Rain can be of droplets of-
Different sizes
Rain can have different intensity of-
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Number of drops per unit volume
Volume of water per unit volume
Volume of water per unit time.

8. Controlling Rain
Fortunately, it is easy for us to create a rain like atmosphere
in a small area.
By selecting proper shower type, nozzle diameter, feed waterBy selecting proper shower type, nozzle diameter, feed water
pressure etc., we can have a good control on droplet sizes,
size distribution as well as quantity of water sprayed.
By having a properly designed equipment, we can even
collect the contaminated water, and decide to reuse it if
contamination is not too severe.
This way, less water is used; and the reject water quantity
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This way, less water is used; and the reject water quantity
would also be less, which can be either sun dried or reused
after treatment.

9. What’s Next?
Imagine you have a vertical conical tunnel, say with an height
of 8-10 meters.
The top of it, having a diameter of say 3 meter, has a big fan.
With a typical air flow capacity of 50,000 cubic meters per
hour.
At the bottom, the diameter is say 1-1.5 meter and the
tunnel is kept around 2 meter elevated from the ground.
At around 2 meters from the top, there is a grid of pipes
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At around 2 meters from the top, there is a grid of pipes
having showers of different type and size nozzles to spray
water in different droplet sizes.

10. Run the Unit!
As you switch on the unit, it sucks air from the bottom,
which is washed using water droplets.
The conical shape helps maintaining higher air velocity in
upward direction at bottom, and lower velocity at top; thus
maintaining adequate retention time for all sizes of droplets
and getting good efficiency.
At the bottom, excess water is collected in a tank and a part
of that is sprayed again.
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of that is sprayed again.

11. Initial Trials
Initial trials can be taken near higher polluted areas, with
monitoring ambient and washed air characteristics. Such
areas could be public places like bus station, railway station,
busy road crossings, industrial areas etc.
The unit can be operated for 10-20 or even 24 hours a day,
depending upon the level of pollution.
After successful operation, similar units can be installed in
other areas of city.
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other areas of city.

12. Who Can Make These?
I personally feel, most of the Indian cooling tower
manufacturers have the capability to design and manufacture
such units.They just need to ask their design team.
There are plenty of Indian suppliers to offer high efficiency
fans and shower pumps.
Shower nozzles of world class quality are also available in
India.
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13. Costs
The typical cost of a unit could be less than a couple of lakhs,
so this is not a very costly option. Each unit can treat nearly
one million cubic meter of air in a day.
The electricity consumption, which has the major share in
operating costs could be around 250-300kWH per day per
typical unit.
Well, this is just a concept, maybe we need to wait for
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Well, this is just a concept, maybe we need to wait for
prototype models in near future.

14. Please do share, if you agree that this approach can
be used to fight smog.be used to fight smog.
ThankYou.
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Please send your comments and feedback to:
D K Singhal
deveshksinghal@gmail.com