How do CFC's affect our ozone layer?

Question

I'm doing a project on the ozone layer and I have to give experimental evidence of what the CFC's do to the ozone layer. It's really confusing and I need help. I also need to know about the ozone hole..

Answer 1

The production and destruction of ozone in the stratosphere are nearly in balance, thus we say ozone is in a steady state. The steady state means that for every ozone molecule that is destroyed, one is produced. This steady state is imbalanced by chlorine chemistry that increases the loss rate of ozone and leads to a lower steady state level of ozone. Most of the chlorine present in the stratosphere is the result of chlorofluorocarbons (CFC's) produced by humans. CFC's were used heavily as a coolant in refrigerators and air conditioners, as a propellant in aerosol cans, and other uses from the 1940's to the 1980's. The production of CFC's was banned in developed countries in 1995. CFC's were considered safe because CFC's are inert or non-reactive. While it is true that CFC's are inert in the troposphere, they are not inert in the stratosphere. In the presence of high energy UV light in the upper stratosphere, the carbon-chlorine bond is broken. This produces a free chlorine atom (Cl) that reacts with an ozone molecule (O3) to form chlorine monoxide (ClO). The chlorine monoxide then reacts with an oxygen atom (O) to form an oxygen molecule (O2) leaving the chlorine atom free once again to destroy another ozone molecule. A chlorine atom can remain in the stratosphere for many years and destroy many ozone molecules. One chlorine atom can destroy up to 100,000 ozone molecules. The steady state, or the balance between production and loss of ozone, has been disrupted by the presence of chlorine in the stratosphere. The reaction is shown below.

CF2Cl2* + UV => CF2Cl + Cl

Cl + O3 => ClO + O2

ClO + O => O2 + Cl


The most obvious effect of this chlorine chemistry is the "ozone hole," which opens over Antarctica in the Southern hemisphere's spring (which is fall in the Northern hemisphere). Check out NASA's data on the "ozone hole" and a top story from NASA about the Antarctic "ozone hole".

In the Northern hemisphere, different weather conditions in the stratosphere prevent the formation of an obvious ozone hole, but chlorine and other anthropogenic (man made) gases may be affecting ozone levels. Therefore, we need to monitor and study ozone at high-latitude sites such as Fairbanks. Check out articles about Arctic ozone depletion at NOAA and NASA.

Answer 2

CFC was once a widely used chemical because it was so stable, that it didn't react with anything. They used to put it in aerosol cans as a propellent and it wouldn't interact with the chemicals in the can. It was used as refregerants, for making styrofoam, and all sorts of stuff.
People thought, it's so stable, how could it be harmful to the environment? Well. because it is stable, it does not degrade so it remains in the environment. And it turns out that it *does* degrade... when it reaches the upper stratosphere. In the strastophere, there are O3 [ozone, which shields us from UV-B] as well as O2 [oxygen, which shields us from UV-C]. Above the layers that contain these gasses, the CFC is broken down by the UV radiation.

The chlorine atom that is broken off from the CFC under these conditions act as a catalyst to breakdown ozone into oxygen (O2--which will not protect against UV-B). Once the chlorine is done with one ozone atom, it is free to destroy more. One molecule of chlorine can destroy 100,000 molecuels of ozone.

CFC is now banned, so there should be very little being released into the atmosphere today, but as I said before, they are quite stable, and they stay in the atmosphere for a long time, so it will be decades before the CFC ban will translate to mending of the ozone hole. ... but it will happen eventually.

Naturally, ozone is constantly being formed and destroyed in the stratosphere. We just need to make sure that the rate being destroyed does not exceed rate being formed.

There is a significant thinning of ozone over antarctica. There is something about the air movement and the cold temperature that concentrates the CFCs to this area more than other places, thus creating a "hole"

Answer 3

Production Of Cfcs

Answer 4

Here I found this for you:
ourozonelayer.blogspot.ca
It's about Canada's ozone layer but it can apply to any ozone layer.

Answer 5

Only one thing to add....the reactions between chlorine and ozone only occur at temperature below -180*F. The coldest temperatures on earth are at the south pole hence it has the largest ozone "hole".

Answer 6

Cuntucky fried chicken does effect our ozone layer....lol