Since the banning of CFC in industry (Montreal Protocol, 1989), ozone depletion has mostly stopped with some signs that levels are increasing. Scientists believe that ozone will return to its pre-CFC level by about 2050.Ways to Protect the Ozone Layer:
Actions an Individual Can Take (see the link below for more):
This is a question with an infinite number of answers, since it calls for personal opinion. I would suggest you review the answers to the questions listed in the related questions section below, and make your own choice.
CFCs and similar man-made gases break down the ozone in the stratosphere allowing in harmful ultraviolet radiation. The ozone hole happens mostly in Antarctica where four months of winter darkness create ideal conditions for the destruction.
Ozone is a protective layer in the upper atmosphere. It is formed, when oxygen molecules absorb short wavelength ultra violet radiations from the sun. Ozone is mostly destroyed by the free radicals in the atmosphere. When compounds like CFCs (chlorofluorocarbons) are released, they are dissociated by sunlight into chloride radicals. These radicals attack ozone, thereby decreasing its concentration. This results in hole in the ozone layer.
The hole in the ozone layer happens because the ozone in the stratosphere is destroyed by chlorine and bromine from halogen atoms. These atoms come from man-made halocarbon refrigerator gases (chlorofluorocarbons [CFCs], freons and halons) which are emitted at ground level but move up into the ozone layer. These gases all contain chlorine and bromine.
Ozone (O3) is formed when ultraviolet (UV) light strikes an oxygen molecule (O2), converting it into two oxygen ions (O). These oxygen ions (O) combine with other oxygen molecules (O2) to form ozone (O3). Later, another oxygen ion (O) will combine with the ozone molecule (O3) to form two oxygen molecules (O2). This is the natural ozone-oxygen cycle of the earth.
The ozone layer prevents the harmful ultraviolet B-waves (UV-B) from reaching the earth. Increased exposure to UV-B is thought to be responsible for increases in skin cancer, eye cataracts and damage to plants and plankton. Because of this the nations of the world in 1989 adopted the Montreal Protocol which bans production of CFCs, halons and other ozone-depleting chemicals.
The ozone hole happens during the spring in Antarctica (Sept to Dec). Polar Stratospheric Clouds (PSCs) form during the all-dark winter. When spring arrives and UV light appears again, crystals of ice and nitric acid in these clouds help to release the chlorine and bromine atoms from the halocarbon gases. These destroy the ozone. (A single chlorine atom can continue destroying ozone for up to two years, reacting with up to 100,000 ozone molecules.)Another view:Natural issues:
Because the concept of man made pollution doesn't cover all of what we see, another look at the issue is demanded. In the man induced theory, the depletion of ozone is due to release of man-made chemicals such as chlorofluorocarbon (CFC) compounds.
Over time these heavier then air chemicals work their way up into the upper stratosphere. CFC's break apart under UV radiation releasing chlorine atoms that would destroy ozone.
Assuming this man induced theory on the origin of the ozone hole is correct, the area most affected would be the mid-Latitude Northern Hemisphere where the industry and population centers in the U.S., Canada, Europe, India, Asia, Russia, China and Japan exist. This is precisely what is not happening! This area is where the least action occurs.
Instead, we are observing a substantial annual ozone hole in one area only, the Antarctic and then only during times of no sunlight (the polar winter). Once the sun returns, the hole disappears quickly. A substantially smaller hole (NASA calls this the dimple because it is so small) is also known to occur over the world's second cleanest area, the Arctic.
A second issue exists. The sun often generates explosions that produce bursts of high-energy protons. These are called Solar Proton Events. Ozone layer density on Earth can be dramatically affected by SPE's, which can locally decrease ozone content in the stratosphere up to 5%.
Some events that have caused serious dents in our levels of ozone levels can be measured using Nitrate Spike Signatures.
They show us large thinning of our ozone layer occurred prior to the creation of CFC's in September of 1859 and in July 1892.
Thirdly, There is growing evidence that ozone levels at the poles is directly connected to the strength of our magnetic fields. The ever weakening fields are believed to be assisting with the size and strength of the ozone hole. Projections for the hole, if tied to magnetic levels of the planet, are for an increasing hole, despite the banning of CFC's.
It is unfortunate that many confuse ozone depletion (which could be a man induced issue) with this natural event. Please see the related link below for a peer reviewed explanation of the natural event we refer to as the hole in the ozone layer;
Bad gases such as Carbon Dioxide and other fumes harm the Ozone layer. CFC (A fluorocarbon with chlorine; formerly used as a refrigerant and as a propellant in aerosol cans) is also the main problem in which the ozone has become thinner. It has been banned in 1966, but the effects are still slow.
The ozone hole is a natural event that occurs when it is winter at a pole. UV-C is required to replace ozone that is decayed (naturally or otherwise), and in winter at a pole, it gets no UV-C, so the ozone decays to very low levels. It also heals up towards spring, such that there is no ozone hole once UV-C from the Sun arrives.
See "How did the ozone hole occur?"
The "hole" in the ozone layer is not a hole in any real sense of the word, but a thinning of the amount of ozone in the atmosphere over the Antarctic during the end of the winter. This hole has been naturally occurring for centuries and is due, almost exclusively, to the lack of sunlight over this area during the long winter. A smaller, but similar situation occurs over the Arctic during the end of it's winter months. NASA refers to this thinning area as the dimple due to the small size when compared to the Antarctic's situation. Solar activity is also a known issue for the amount of ozone in our atmosphere. The largest known thinning of that we know of actually occurred in 1859 and is believed to have been caused by solar activity. CFC's are also having some contributory affect on the amount of thinning of the ozone.
Ozone depletion was observed to increase as emissions of halo-carbons increased.
Ozone is a protective layer in the upper atmosphere. It is formed when oxygen molecules absorb short wavelength ultra violet radiations from the sun. Ozone is mostly destroyed by free radicals in the atmosphere.
When compounds like CFCs (chlorofluorocarbons) and other halocarbons are released, they are dissociated by sunlight into chloride radicals. These radicals attack ozone, thereby decreasing its concentration. This results in a thinning of the ozone layer, and in polar regions, a hole.
The holes occur at the poles, and usually in Antarctica because of the extreme cold. During the winter polar stratospheric clouds form which are able to convert gases in the atmosphere into Cl (chlorine) and ClO (chlorine monoxide). When the sun arrives at the end of winter, that is the trigger to begin. This is why the hole is largest in spring.
The ozone hole occurs once a year at each pole. The southern polar hole is larger than the northern polar hole due the fact that the southern pole is much colder than the northern pole. The size of the hole is what is of concern and is caused by chlorofluorocarbons (CFCs) and halogens from human industry.
Ozone decays naturally with time. With the axial tilt that Earth has, once each year (local winter) each pole stops receiving the UV-C that turns some oxygen into ozone. So the ozone starts decaying, and a hole forms. The only ozone the pole gets at this time, diffuses in from areas that are still receiving UV-C. So the ozone would be exceedingly thin at this time. The presence of the polar jet stream prevents the ozone at the poles (during local winter) from being replenished as it is throughout the year otherwise.
Add contaminants to the mix, and the amount of ozone drastically decreases. Water vapor (natural and Man-sourced), chlorine (most commonly Man-sourced, carried by CFCs), and bromine (most commonly natural, but likely some Man-sourced, carried for example in halon) all have shown abilities in depleting ozone.
The concentration of ozone at any point is a balance of incident UV-C from the Sun (both making and destroying ozone), UV-B from the Sun (destroys ozone when absorbed), time, and compounds that can accelerate the decay of ozone.
The southern hole is larger because it is so much colder. It is cold enough to form something known as Polar Stratospheric Clouds (PSCs). These form a deposition site for the radicals in the atmosphere that are responsible for ozone depletion. These radicals can be recycled after use so that one molecule of contaminant (chlorine) is responsible for the destruction of several thousand molecules of ozone.
The ozone layer is a thin layer of ozone that protects the earth from dangerous ultraviolet light. When the layer is thin or damaged this ultraviolet radiation can cause eye cataracts, skin cancers and damage to crops.
The ozone layer is a region high in the stratosphere, containing ozone (a form of oxygen) that filters out most of the Sun's dangerous ultraviolet rays (UV-B). This UV-B could otherwise be absorbed by the DNA in all surface dwelling life on Earth. Ultraviolet radiation can cause cataracts, cancer, and mutation. It can also reduce crop yields, and damage arable land.
The ozone is located between 4 and 10 miles above the surface of the Earth (lower near the poles), with the highest ozone concentrations in a region that is variously called the lower stratosphere, the tropopause, or simply the "ozone layer".
Ozone itself is a triatomic molecule, composed of three oxygen atoms that bonded, unlike the oxygen we breathe, which are diatomic molecules, meaning two oxygen atoms. The "ozone layer" contains more than 90% of the earth's ozone. Ozone is a corrosive, light blue gas with a smell something like burning electrical wiring. The atmosphere at this altitude is still about 78% nitrogen, 21% oxygen, and the peak ozone concentration is about 9 ppm (or 0.0009%). Other things (water vapor, carbon dioxide, argon, and so on) are present there in small concentrations too.
The ozone layer has been depleted during the 20th century by chlorofluorocarbons (CFCs) and halogens. When the damage to the ozone layer became clear during the 1970s the Montreal Protocol, an international treaty to limit their production was set up, and came into force in 1989. Despite this phasing out, ozone levels in the stratosphere are still low and scientists predict they will not recover until 2050.
An ozone hole also periodically forms, since ozone is unstable. The word "hole" is somewhat misleading. This is actually a diminished concentration of ozone due to the lack of sunlight and not a complete absence. An ozone hole forms over a pole, then later closes, once each year at the pole that is not receiving UV-C light from the Sun. The southern polar hole is larger than the northern polar hole, due to the polarity of Earth's magnetic field. Chlorofluorocarbons (CFCs) make the hole larger, last longer, and contain less ozone, which is only an indication of the general "health" of the ozone layer. The hole itself forms in areas that are receiving no UV-B from the Sun either, so there are no lifeforms at risk from our Sun directly "beneath the hole," but every surface organism is at risk from a thinned ozone layer.
If you took all the ozone in an entire column from the ground to infinity, and compressed it to STP (standard temperature and pressure, or 0°C at 1 atmosphere pressure) it would be a layer about 3 mm thick. There is less than 1/3 as much in the Antarctic "ozone hole" when it is winter there.
Yes, the ozone layer filters out all the UV-C (the most dangerous ultra-violet radiation) and most of the UV-B. The least dangerous radiation is UV-A, and most of this reaches the surface of the earth.
Oxygen and nitrogen are the primary absorbers of UV-C and more energetic light (X-rays, gamma rays from space), and they do this completely by the lower stratosphere. One side effect of their absorption of this light, is they make ozone. This ozone is concentrated here, since it is unstable, and the "ozone layer" is formed. Some recombines into N2O*, which later forms either ozone or more stable NOx (if it encounters water vapor first). Some single oxygen atoms encounter O2 and make ozone directly.
Ozone absorbs UV light shorter than 260 nm or so. This includes UV-B, UV-C and more energetic light. Only ozone in our atmosphere absorbs UV-B, which would otherwise be stopped only by soil, meters depth of water, or the DNA of all surface life on Earth.
Additionally, the natural and Man-made "greenhouse gases" in our atmosphere (carbon dioxide, water vapor, ozone, for examples), serve to allow visible light and UV-A in to Earth's surface, but moderate the transmission of infrared light back to space... keeping Earth a tad bit warmer than it would otherwise be without an atmosphere.
Long wave UV (UV-A) and visible light always gets through the ozone layer. As the ozone layer is thinned, additional energetic UV (UV-B) gets through, which will cause problems down here on the surface.
As UV is absorbed, and used in a reaction O3 + uv light = O + O2 ,
Ozone directly absorbs UV-B and either becomes oxygen, or becomes ozone again, with the light scattered again in random directions.
When UV hits the Ozone (O3) it is 'absorbed,' meaning the energy is used to split the ozone into Oxygen gas (O2) and an Oxygen free radical (O). The remaining energy from the UV light is re-emitted as infra-red (heat).
O3 + UV-B -> O2 + O
The Ozone layer is situated on the upper stratosphere. Ozone (O3) is very unstable gas. Ozone is the only gas in our atmosphere that absorbs UV-B.
Oxygen and nitrogen molecules absorb UV-C and more energetic light, and later recombine in different forms. Oxygen atoms sometimes recombine to form ozone, and this primarily occurs in the lower stratosphere... and forms the ozone layer.
Oxygen and nitrogen protect us from very short wave UV, by absorbing the light and breaking apart.
Similarly, ozone has an extra resonance (than its parent oxygen), and can absorb less energetic UV, stuff that still causes cancer, and ozone breaks apart into oxygen gas and a oxygen atom looking for a place to land.
Infrared radiation such as the sun which is blocked by the ozone layer. Such as why to much time in the sun will give you skin cancer. Also it reminds you of when you go to the dentist, whoever is taking your x-ray never stays in the same room and that is why they put a huge metal pad over you. If they did not, it might give them cancer.
Oxygen and nitrogen absorb UV-C. Some of the "shattered" oxygen forms ozone. The UV-C mostly ends up as both heat, and re-emitted as less energetic light in a random direction.
Ozone absorbs UV-B (and some UV-C). The UV-B mostly ends up as heat, and re-emitted as less energetic light in a random direction. Some of the ozone is destroyed in the process of absorbing UV-C or UV-B, and little of it reforms as ozone.
Since atmospheric gases have very low absorptivity / emissivity at visible and IR wavelengths, they do not contribute to heating the surface of the Earth to any great extent. Ozone does have some limited resonance in the IR range, which is why it is called a greenhouse gas too. But it has very low concentration.
UV- C is filtered out but UV-A and UV-B however are not. UV-B is the radiation which begins oxidization of your skin and UV-A is the rays in which change the pigmentation of your skin togive you a tan, UV-C is the only extremely harmful rays and the ozone layer does in fact block them out.
The ozone in the earth's upper atmosphere uniquely absorbs UV-B from our Sun, which would otherwise directly damage the DNA of all surface life... cataracts, melanoma, mutation, and decreases in crop yields. See "What does the ozone layer do?" link below for more. On one hand, long wave ultraviolet light (UV-A) striking the skin produces natural vitamin D in the body, which helps metabolize calcium into bone tissue. On the other hand, short wave ultraviolet light is ionizing radiation which can produce skin cancer. At ground level, ozone is a respiratory irritant, and can aggrivate the respiratory tract and also asthmatic conditions as the ozone is so reactive, it reacts with substances like mucus membranes in your body. Ground level Ozone is most commonly produced by burning fossil fuels, which release oxides of nitrogen (NOx) and unburned fuel. Sunlight converts them with Oxygen in the air to produce Ozone. Ozone can cause breathing difficulties, headaches, tiredness, and in extreme cases... death. Ozone will do everything that oxygen will do, and some things that it won't. It is a powerful oxidizer and is much more powerful than oxygen alone. There are some adherents to alternative medicine who claim many "cures" using ozone. However, there appear to be legitimate medical uses for ozone; see the Related Link. It purifies water--most of the bottled water you see says "purified by ozonation" on it. They use an air stone (or eductor) to bubble ozone through the water, and the ozone kills any organisms that might be living there. Eductors are today more commonly used to apply ozone to drinking water, since eductors do not provide tiny difficult to clean pores in a drinking water system like diffuser stones do. They also provide the possibility of applying ozone into pressurized systems. Ozone is applied into sewer manholes, where it dissolves grease (along with water vapor) and destroys odors (however briefly). Ozone is applied to municipal water (in some cases), where it will destroy pharmaceuticals, destroy taste and odor, make organic molecules easier for activated cabon to destroy, sterilize the water, and act as a flocculant (agglomeration of contaminant molecules that can settle or filter more easily). In organic synthetic chemistry, ozone is used in as a reagent in ozonolysis reaction that oxidize a carbon double to two aldehydes. This is a very useful reaction but dangerous.
In short they attacked and slowly depleted the ozone layer (however they didn't destroy it fully)
No. I believe UV is scattered in all directions just as the other wavelengths, which means you can get burned even in the "shade". But either wave, UV is no more or less intense after passing through clouds.
Evaporation is a primary issue as is a lack of sunlight. Without sun the hole starts.
Processes would include solar activity. The largest know hole occurred in 1858, during a heavy solar flare.
Some believe, and there is some evidence to show it is possible, that CFC's contribute in some manner to the hole that occurs annually above the Antarctic.
Ozone breaks down in the ozone layer in the following major ways:
CFCs, HCFCs, and Halon:
The ozone layer is destroyed by CFC's, chlorofluorocarbons, that are used as a propellant in aerosol cans, and refrigerants in older cars and refrigerators. When Chlorofluorocarbons (Freon and other CFCs) and Bromofluorocarbons (Halons) they became popular refrigerants and fire fighting agents. As the compounds were inert and thought to pose no damage to health or the environment they were handed without much consideration for losses. As a consequence the concentrations of these materials built up in the atmosphere. However (there's always a however) when the materials reached the stratosphere the were acted on by ultraviolet radiation and broke down releasing chlorine and bromine into the ozone layer. The ozone layer is the earth's ultraviolet shield. The chemistry is such that the chlorine and bromine attack the ozone, reducing it to ordinary oxygen which as no shielding effect from UV-B. The complex chemical reactions allow the chlorine and bromine to interact again and again with ozone molecules, until they eventually leave the ozone layer bonded to some other compound. Since the Montreal Protocol was developed to control and ban the use of these compounds the ozone layer has improved. But due to the long-lasting impact the problem will not be resolved totally for many years.
The ozone layer is strongly negatively affected by the presence of water vapor. Not only does it suppress the formation of ozone, but it provides another decay path. Whenever there is large quantities of anomalous stuff associated with an ozone hole (clouds, NOx, more), it is compounds that are daughters of the suppression of ozone by water vapor. Water vapor carried in some part by high altitude aircraft (which also reduce the oxygen locally from which ozone is made).
Depletion of available oxygen:
Ozone is formed from oxygen. Processes / actions that reduce the viable plant life that make oxygen, are depleting ozone. Ozone is not "leaving the Earth", it is not being harvested by aliens, or being sprayed into deep space. Ozone is unstable (it decays with time, back into oxygen), it will attack any other molecule that is not protected by fluorine, and it breaks down when UV-B or more energetic light hits it. Our ozone layer depends on UV-C from the Sun to make some new "fresh" ozone each day, some survives all night long. Contaminants, as described above, decrease the equilibrium ozone concentration. Allowing more UV-B to arrive at Earth's surface, and damage us and our food sources.
The ozone hole size as a measure of overall ozone depletion:
Some of the ozone hole is natural. Some of the depletion of ozone is due to "natural factors". Man-made chemicals seem to be concentrated in regions of low ozone concentration, and these have been otherwise shown to destroy ozone. Man also dumps water vapor high in the atmosphere, and water vapor also destroys ozone. Assessing the damage we have done to the ozone layer will be hard to do without more data. We had a record sized ozone hole (2006) and we have not decreased too much percentage-wise since then (2008). But we simply don't know how much we are responsible for. Does it matter? We are not required to feel guilty. We are stewards. This is our home. We know what we have to do to help Nature repair the damage (and any damage is reversible, hopefully without eliminating Man first). When CFCs are present in the stratosphere they reacted on by ultra violet light to release a chloride ion. The ion breaks down an ozone molecule to create an oxygen molecule and ionic oxygen. The ionic oxygen releases more chloride ions to break down more ozone and CFCs
The end result is the ozone is converted to oxygen quicker than natural processes can replace it Ozone depletion may be occurring because of the inadvertent actions of Man. It appears that water vapor in the upper atmosphere and compounds like CFCs have increased due to the actions of Man. It depletes every year at the pole, when it is winter at the pole. Ozone decays with time, and there is no UV-C from the Sun to make more when that pole is having winter. Not sure it is being entirely destroyed. Ozone has even been found on Mars, and it has almost no free oxygen. Mostly likely candidates for the thinning of the ozone layers are:
Chlorine and chlorine-based compounds, create a surface on which ozone can be broken apart or destroyed. This is mainly why CFC's (chlorofluorocarbons) were banned by law, because they destroyed ozone. Note that the prefix chloro is in chlorofluorocarbons, meaning that the reason ozone was destroyed by CFC's was due to the fact that CFC's were chlorine-based compounds. because they made a hole in it. Chlorofluorocarbons are the main cause of global warming. It's kind of like if you burnt a hole in a piece of paper it can't be fixed.
Ultra Violet Rays:
The sun's ultra violet rays are also damaging the ozone layer from the outside because the ozone layer protects us from the sun's harmful rays while we are depleting the ozone layer from the inside by releasing carbon dioxide and other ozone depleting substances into the atmosphere.
Chlorine atoms break away from the CFCs and destroy the ozone molecules. This allows harmful UV radiation to reach the earth.
Most of the sun's harmful energy does not go through the ozone layer.
From the top down:
(the ones with stars next to them are sub-layers)
nm = nanometers
It is a measure of the wavelength of the light, with energy inversely proportional to the wavelength: E = h / wavelength
Global warming and climate change alters earth's normal doings, thereby affecting its weather patterns and changing the conditions of its various spheres.
Possible effects of global warming include;
In many areas droughts are more severe than would be otherwise, leading to increased danger of fire or crop failure. Ocean levels, of course, continue to rise. This has not yet resulted in substantial coastal flooding, but the rate is projected to increase.
Extinctions are expected to continue, with climate factors gaining on and exacerbating habitat loss. Plant and animal ranges are expected to shift to higher latitudes, some of which has already been observed.
To stop the ozone hole, curb CFC's. They are the ones that deplete ozone.
The ozone hole can be reduced by:
There are many ways to stop the ozone hole. Stop Aerosol sprays, stop AC's, stop deodorants, stop CFC's.
CFC's react with ozone and cause a hole in the layer.
just make becky sit on it :)
Ozone layer thinning is most pronounced over the poles because of a no of factors some of which are:
1) The CFC's released by humans are carried towards the poles by the westerlies or the westerly winds where they cause ozone depletion.
2) the poles are the regions having low temperature and the ozone depleting reactions are only carried in temperature below -2o temperature that is on the polar stratospheric clouds. This attainment of temperature as low as 2o is only possible on the poles
Carbon dioxide is not destroying the ozone layer directly but its adverse effects can be seen on the ozone layer indirectly.
Carbon dioxide leads to global warming which does not allow the heat to escape out because of which the temperature for the production of ozone is stopped.
The rate of production is less than rate of depletion which causes ozone layer to deplete.
Ozone needs constant sunlight to replenish itself, especially now when it is being destroyed by CFCs which will remain in the atmosphere for at least another 50 years, even after we stop releasing them.
The North and South Poles have six months of darkness, so during that time no ozone is produced. The South Pole is much colder than the North Pole and the frozen clouds also help to release the chlorine from the CFCs. This is why the ozone hole is largest at the South Pole, the Antarctic.
Many things can be done to prevent depletion of the Ozone (Ozone Layer)
(a little background...) Ozone is comprised of 3 oxygen atoms, known as O3. When we hear the term Oxygen, it is usually referring to the Oxygen that we breathe, known as O2. O2 is a necessary component for life (almost all life) on Earth's surface - it is the form of Oxygen that we breathe; it is used in cellular respiration in animals and photosynthesis in plants. Ozone, or O3, is in fact toxic to living creatures, but without it we would be in a lot of danger - So how does that work? Ozone, is naturally found in the upper level of our atmosphere. It absorbs many of the harmful rays of the sun, known as Ultraviolet radiation (UV-A, UV-B and UV-C) which can cause cancer and cellular damage. Pollution is a major source of depletion of the Ozone layer. Many man-made pollutants contain compounds called Chlorofluorocarbons (CFCs) and bromofluorocarbons. These compounnds can rise to the upper level of our stratosphere Where UV light breaks them into free radicals of Chlorine (Cl) and Bromine (Br). Each of these radicals is then free to react with O3 and catalyze a chain reaction capable of breaking down over 10,000 ozone molecules. IN SHORT- the compounds in Pollution from factories and aerosol cans can destroy ozone molecules, To prevent this laws have been passed to stop and control production of these compounds. You as an individual can help by lobbying in Congress, supporting environmental organizations and spreading the word to your friends, family and anyone you know about the causes and prevention of damage to Ozone.
Because 2O3 --> 3O2 is exothermic
carbon dioxide, methane, and water vapor are the main ones
There are four factors of production: Land, Labor, Capital and Organization.
In any business entity production process is completes through employing these factors of production.
Land gets the rent, labor gets wages, capital the interest and organization gets the proft earned by any business entity.