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Q & A: How to Make Ozone

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Q:
Is there anyway we can 'recover' the ozone layer?
- kengfoo (age 13)
Anglican High, Singapore
A:
Kengfoo -

Youíve asked an important question because, as you know, we need to keep the ozone layer because it protects living things from deadly ultraviolet radiation.


Actually, itís really easy to make ozone. Ozone is produced naturally when sunlight shines on air. It is produced by a chemical reaction in which several molecules of oxygen react with each other. But this reaction only takes place when thereís sunlight. So as long as itís sunny, ozone will constantly be produced. The reason that we have problems with the ozone layer is that some chemicals like chloroflourocarbons (CFCs; for example, the freon from your freezer or air conditioner) trigger reactions that destroy ozone.. So we have one reaction that makes ozone and one that destroys it. The net ozone level depends on how fast the creation and destruction reactions occur.When pollutants speed up the destruction reactions, the ozone level drops.


At the North and South poles, the way that the Earth rotates causes it to be dark practically all the time in the winter (and light during the summer). So during the winter there is ozone being destroyed but not being made, making a temporary "hole" in the ozone layer. But once summer comes around and itís sunny all the time, new ozone will be made, and the hole goes away. Of course the ozone level doesnít quite get back as high as it used to, so long as there are still pollutants up there destroying it.


The key point here is that we donít need to do anything at all to recover the ozone layer. It will recover by itself, once we quit doing things to destroy it. Full recovery can be slow, because the CFCs last many years in the upper atmosphere.

Mike & Tamara

(republished on 08/01/06)

Follow-Up #1: Ozone production and storage

Q:
how much ozone can you produce at a time? can you store it?
- teto (age ivan)
cardiff, wales
A:
The main thing is that ozone is unstable and doesn't live very long so it is impractical to make a large quantity and store it.  Most big-time users of ozone, like drinking water treatment systems, install generators on the spot and make it as needed.   Several manufacturers make these generators.  Almost all of them work on the principle of injecting oxygen, either in the form of air or pure oxygen, and subjecting it to a high voltage electric discharge.  The spark produces ultra-violet light which breaks apart an oxygen molecule, O2 , into two O ions.   These in turn react with another oxygen molecule to make ozone  O3 .
I don't know at what rate these generates can make ozone, you would have to contact a manufacturer to find the specifications.

LeeH

(published on 09/28/11)

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