why is their a huge ozone hole over "Antarcatica" but not over a very polluted place?

Question

This is the title of science fair project. what do u think is it a good title or too simple?

Plz tell me some good ideas for science fair project because iam participating in a tough competetion.

I will be thankful to u all !!!!!

Answer 1

The term ozone depletion is used to describe two distinct but related observations: a slow, steady decline, of about 3% per decade, in the total amount of ozone in the earth's stratosphere during the past twenty years and a much larger, but seasonal, decrease in stratospheric ozone over the earth's polar regions during the same period. (The latter phenomenon is commonly referred to as the "ozone hole".) The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the proximate cause of both trends is believed to be catalytic destruction of ozone by atomic chlorine and bromine. The primary source of these halogen atoms in the stratosphere is photodissociation of Chlorofluorocarbon (CFC) compounds, commonly called freons, and bromofluorocarbon compounds known as Halons, which are transported into the stratosphere after being emitted at the surface. Both ozone depletion mechanisms strengthened as emissions of CFCs and Halons increased. CFCs, Halons and other contributary substances are commonly referred to as "ODS", or "Ozone Depleting Substances." Since the ozone layer prevents most harmful UVB wavelengths (270- 315 nm) of ultraviolet light from passing through the Earth's atmosphere, observed and projected decreases in ozone have generated worldwide concern leading to adoption of the Montreal Protocol banning the production of CFCs and halons as well as related ozone depleting chemicals such as carbon tetrachloride and trichloroethane (also known as methyl chloroform). It is suspected that a variety of biological consequences, including, for example, increases in skin cancer, damage to plants, and reduction of plankton populations in the ocean's photic zone, may result from the increased UV exposure due to ozone depletion.

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.[5]

As 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).

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.

Answer 2

Ozone is is formed less quickly there
O2 + O = O3
due to the lower temperatures. Temperature speeds up chemical reactions.
So if Ozone is depleting across the whole world, this is the first area where it must go.

Answer 3

well if you're just looking for a good title, how about:

Suntanned penguins or
Pollution's effect on preserved areas
or The Ozone: nature's sunblock

Answer 4

On the first date...

Answer 5

What about - is it better to be a polar bear or a fox?