If most of the use of Freon-12 is in the northern hemisphere, then why is the ozone hole over Antarctica?

If most of the use of Freon-12 is in the northern hemisphere, then why is the ozone hole over Antarctica? Asked by crispy 58 months ago Similar questions: Freon 12 northern hemisphere ozone hole Antarctica Science.

Similar questions: Freon 12 northern hemisphere ozone hole Antarctica.

Ozone hole There is depletion of ozone everywhere but the effect is strongest at the poles, especially Antarctica. Below is an excerpt from Wikipedia but to summarize, while chlorine compounds can destroy ozone while in gas form but do an even better job in clouds. Clouds form in the cold and sunless Antarctic winters. When sunlight returns in spring, the ozone destoying rection takes off.

------------------------The Antarctic ozone hole is an area of the Antarctic stratosphere in which the recent ozone levels have dropped to as low as 33% of their pre-1975 values. The ozone hole occurs during the Antarctic spring, from September to early December, as strong westerly winds start to circulate around the continent and create an atmospheric container. Within this "polar vortex", over 50% of the lower stratospheric ozone is destroyed during the antarctic spring.6As explained above, the overall cause of ozone depletion is the presence of chlorine-containing source gases (primarily CFCs and related halocarbons).

In the presence of UV light, these gases dissociate, releasing chlorine atoms, which then go on to catalyze ozone destruction. The Cl-catalyzed ozone depletion can take place in the gas phase, but it is dramatically enhanced in the presence of polar stratospheric clouds (PSCs) FAQ, section 7. These polar stratospheric clouds form during winter, in the extreme cold.

Polar winters are dark, consisting of 3 months without solar radiation (sunlight). Not only lack of sunlight contributes to a decrease in temperature but also the “polar vortex” traps and chills air. Temperatures hover around or below -80 °C.

These low temperatures form cloud particles and are composed of either nitric acid (Type I PSC) or ice (Type II PSC). Both types provide surfaces for chemical reactions that lead to ozone destruction. The photochemical processes involved are complex but well understood.

The key observation is that, ordinarily, most of the chlorine in the stratosphere resides in stable "reservoir" compounds, primarily hydrogen chloride (HCl) and chlorine nitrate (ClONO2). During the Antarctic winter and spring, however, reactions on the surface of the polar stratospheric cloud particles convert these "reservoir" compounds into reactive free radicals (Cl and ClO). The clouds can also remove NO2 from the atmosphere by converting it to nitric acid, which prevents the newly formed ClO from being converted back into ClONO2.

The role of sunlight in ozone depletion is the reason why the Antarctic ozone depletion is greatest during spring. During winter, even though PSCs are at their most abundant, there is no light over the pole to drive the chemical reactions. During the spring, however, the sun comes out, providing energy to drive photochemical reactions, and melt the polar stratospheric clouds, releasing the trapped compounds.

Most of the ozone that is destroyed is in the lower stratosphere, in contrast to the much smaller ozone depletion through homogeneous gas phase reactions, which occurs primarily in the upper stratosphere. Warming temperatures near the end of spring break up the vortex around mid-December. As warm, ozone-rich air flows in from lower latitudes, the PSCs are destroyed, the ozone depletion process shuts down, and the ozone hole heals.

Sources: http://en.wikipedia.org/wiki/Ozone_hole#The_ozone_hole_and_its_causes .

Polar Stratospheric Clouds... There are far more detailed explanations available on the web, but here is a short summary. Ozone depletion is primarily caused by chlorine containing gases. When the chlorine is released from the molecules, the chlorine acts a a catalyst causing the ozone depletion.

The chlorine containing gases are well mixed into the atmosphere globally, not just centerd in either the Antarctic or above major CFC sources. During the Antarctic winter, there is no exposure to sunlight for roughly 3 months, which contributes to extremely cold temperatures. The temperatures contribute to the formation of polar straospheric clouds.In essence, a situation is created in which the chlorine containing gases are trapped in the clouds above the Antarctic continent.

The presence of the clouds causes even cooler temperatures, which leads to the formation of nitric acid or ice particles. Once the particles form, they provide a surface upon which the ozone depletion takes place. Under ordinary circumstances, the chlorine is locked up in "reservoir compounds", which are relatively benign.

With the presence of the ice or nitric acid particles, the molecules reform as "reactive free radicals" which are much more conducive to the ozone depletion process. This buildup takes place throughout the Antarctic winter, but very little depletion takes place. When the Antarctic spring begins, sunlight provides the energy necessary to start the depletion process.

Also, the clouds are heated, causing them to breakup and free the new compounds over a larger area, increasing the area of ozone depletion. Eventually, the temperature rises enough to break up the PSC, which allows warmer ozone-rich air into the system. This effectively shuts down the depletion process, until the temperatures decrease in the following winter.

There is a very good article about ozone depletion on Wikipedia, which I have linked as a source material. Sources: http://en.wikipedia.org/wiki/Ozone_depletion .

Antarctic conditions are "better" for ozone depletion. Freon-12 is a CFC, which has chlorine, which is an ozone-depletion substance. The forces of wind are such that the gases of the stratosphere are mixed together more or less uniformly, which is often considered counterintuitive since CFCs are heavier than air.

Regardless, you end up with uniform spread of this stuff through the stratosphere. Why is the ozone hole over Antarctica? Consider this quote from the link below: Briefly, the unusual physics and chemistry of the Antarctic stratosphere allows the inactive chlorine "reservoir" compounds to be converted into ozone- destroying chlorineradicals. While there is no more chlorine over Antarctica than anywhere else, in the antarcticspring most of the chlorine is in a form that can destroy ozone.

The link goes on to describe the six steps involved in making the Antarctic stratosphere the "perfect" reaction vessel for ozone depletion, the sum of which results in the ozone hole there instead of elsewhere. Sources: http://www.faqs.org/faqs/ozone-depletion/antarctic/ TeeSeeJay's Recommendations Chemical Processes in Atmospheric Oxidation: Laboratory Studies of Chemistry Related to Troposheric Ozone (Transport and Chemical Transformation of Pollutants in the Troposphere) Amazon List Price: $155.00 Used from: $64.26 .

Ozone is created by sunlight Oxygen exists in our atmosphere mostly in the form of O2, or "molecular" oxygen. In other words, two atoms of oxygen are joined together. Ozone is in the form of O3, where three oxygen atoms are joined together.

This form is much more reactive than O2, and at ground level is a component of smog. It also blocks ultraviolet light (broadly speaking. ) sunlight strikes O2, occasionally knocking off an O atom.

These sometime join with other O2 molecules to create O3, or ozone. The atmosphere above the poles is exposed to less sunlight than the atmosphere at lower latitudes, so less ozone is generated there. Ozone is itself rather unstable, and there are a number of things, not just Freon that tends to break it down back into O2.

What matters is the rate of creation versus destruction. At the poles the rate of creation is lower than the rate of destruction. Freon is particularly bad as a ozone destroyer because 1) it isn't consumed as it breaks down ozone and 2) it never breaks down, at all.So any freon released into the atmosphere floats around forever, breaking down ozone.

Where it was released doesn't matter much, since the ozone creation/destruction is taking place many miles up, in the very top of the atmosphere. People also pay lots of attention to Freon because it is entirely man-made, and because there is no good reason to use it. Other compounds are just as effective, and cost about the same (that was not true at first because there wasn't a lot of those substitutes being made at first.

) So it is one of the factors contributing to ozone depletion that we can actually do something about, and fairly easily. And incidentally, it appears that since we have stopped using Freon, the ozone layer is recovering somewhat.It just goes to show what assertive government action can accomplish, if the people want it.

" "True or False. Almost all tundra climates are in the Northern Hemisphere." "askville, where is the northern hemisphere located. Will my kindle work there.

" "My dog walks in clockwise circles before deciding where to urinate.Is it because we are in the northern hemisphere-HA? " "Has the hole in the ozone grown, decreased, or remained the same over Antarctica over the last 5 years? " "how science has destroy the ozone layer" "Why is there a localized hole in the ozone layer over the south pole?" "Is there a connection between the ozone hole and global warming?

" "Whatever happened to the hole in the ozone layer. You don't hear about it anymore. Did we fix it?

True or False. Almost all tundra climates are in the Northern Hemisphere.

Askville, where is the northern hemisphere located. Will my kindle work there.

My dog walks in clockwise circles before deciding where to urinate. Is it because we are in the northern hemisphere-HA?

Whatever happened to the hole in the ozone layer. You don't hear about it anymore. Did we fix it?

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.