Naked Science Forum
Life Sciences => The Environment => Topic started by: ukmicky on 27/08/2005 17:05:30
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As we all know we now have holes in the earth’s ozone layer. But why doesn’t the ozone from outside the holes flow back in and fill the holes.
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I think that the ozone hole isn't a vacuum it is an area with more oxygen and less ozone than normal at that altitude, so the ozone won't rush there quickly - it will all be to do with how fast the ozone is moved there by atmospheric mixing processes and how fast it is destroyed by the CFCs etc... I guess that in the south pole it is being destroyed faster than it is arriving.
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Can ozone be artifically produced and released into the atmosphere.
We could build an ozone replenishment plant[:)]
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Sure. All you need is a way to remove the freons that are catalyzing the breakdown of ozone.
Kind of like you can replenish a woodpile by stacking more wood on it -- only, first, you have to put out the flames that are burning it.
To make ozone, all you need is a source of ultraviolet radiation approximately the size and distance of the sun -- and an atmosphere with oxygen in it, like Earth's.
Don't, however, allow freons to be produced. They convert ozone back to oxygen.
You can't overcome the catalytic effect just by feeding it.
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So thats a no then.
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At the poles, the climate amplifies the effects of ozone depletion. Cold temperatures and an isolated circumpolar vortex combine with naturally occuring chemicals and CFCs in the atmosphere to deplete the ozone. At lower latitudes air circulation is better, so a hole does not develop.
Our host, Cambridge University, has been monitoring stratospheric ozone over the poles since the 50's. Here is a good website about this problem that they host: http://www.atm.ch.cam.ac.uk/tour/
On a more personal note, here is a Wikipedia entry for a spacecraft I was proud to be a principal contributor to some years ago. It was used, together with ground, aircraft, and balloon studies to help understand the ozone problem, but even more- the upper atmospheric chemistry and energy balance problem: http://en.wikipedia.org/wiki/Upper_Atmosphere_Research_Satellite
"F = ma, E = mc^2, and you can't push a string."
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Thanks. I always wondered why the holes didnt just fill back up with the the surrounding ozone.
Now i know
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The ozone hole is a bad thing for humans because as we know ultraviolet light causes skin cancer and eye damage. SO if you live on the southern tip of South America or in South Africa or South Australia, you need sunglasses and extra sunblock. The CFC/ozone layer is another example of the common human technique of solving a problem (uncomfortable hot weather is made pleasant by air conditioning) and thereby causing a worse problem (sun cancer and eye damage from depleted ozone layer). As Hippocrates said: "First, do no harm".
chris wiegard
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Well, maybe it isn't quite so simple. The poles have holes because for half of the year, they receive less radiation from the sun due to the 17 degree tilt of the earth.
Ozone is also generated by lightning storms (very intersting info on what causes lightening in another section of this site). But solor radiation is a major source. (No, the freon doesn't magicly migrate to the south pole to destroy the ozone.)
So one question that needs to be answered is how does solar radiation (which we know varies with sunspot activity) affect and or explain the ozone hole. And just for fun, are there other posibilties to explain the ozone hole. Sorry if this interferes with all the funding going to professors that want to slam freon and other man made chemicals (what is the trasport method to carry a heavy molecule high enough to affect the ozone layer? and what will be the effect of cosmic radiation on the florocarbons?)
Science is also the art of critical thinking.
David
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ozone is heavier than air so even if you did make a lot of it and released it into the atmosphere it would just hang around at the bottom and choke everyone at street level
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quote:
Originally posted by VAlibrarian
The CFC/ozone layer is another example of the common human technique of solving a problem (uncomfortable hot weather is made pleasant by air conditioning) and thereby causing a worse problem (sun cancer and eye damage from depleted ozone layer). As Hippocrates said: "First, do no harm".
chris wiegard
Not quite.
Firstly, CFC's are quite safe – that is why we used them as a refrigerant. We did not create CFC's for air conditioning, we developed them to replace nasty things like ammonia, alcohol, SO2, etc. as refrigerant to keep food cool, long before air conditioning was in regular use (incidentally, it came part and parcel of the technology that created Teflon). CFC's were seen as environmentally safer than the substances they replaced, and at low altitudes they are, and no-one understood how they would react at high altitudes.
The problem with CFC's is that it was too stable, so by the time it did decompose, it had climbed high up into the atmosphere, and when it did decompose, it released chlorine, and AIUI, it is the chlorine that is blamed for the ozone hole.
I doubt that back in the 1930's there was any idea of what ozone was doing up in the upper atmosphere, let alone what the likelihood of adding a bit of chlorine up there might do, or that CFC's would even end up decomposing at such high altitudes. Even today, much of this is speculation, however well informed that speculation might be – we can't even prove how recent the ozone hole is, or whether it might be a regular cyclical thing.
It is easy to blame with hindsight. I just wonder how many things will be found in 50 or 100 years time about the supposed harm that our solutions to our problems might be causing that we could not have imagined might happen?
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Interestingly the first CFCs, known collectively as freon, were invented by Thomas Midgley, who also invented the tetraethyl lead fuel additive! [:)]
He invented loads of other stuff too, clearly a brilliant practical chemist, just really unlucky with those two items. Sadly, however, it is rumoured that later in his career he covered up evidence of lead poisoning in "ethyl" plant workers, and even in himself!
http://inventors.about.com/library/inventors/blfreon.htm