ozone layer depletion causes and effects pdf

Ozone layer depletion causes and effects pdf

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Climate Change

Air Information Resource

Ozone is both beneficial and harmful to us. Near the ground, ozone forming as a result of chemical reactions involving traffic pollution and sunlight may cause a number of respiratory problems, particularly for young children.

She had just been looking at the record of average surface temperatures of the Earth. The year was the warmest since reliable temperature records have been kept, and the twentieth year in a row in which the average global surface temperature was higher than the year average. The next year, , was the fifth warmest on record; the six warmest years on record have occurred in the last decade. If the global warming trend continues, the results could be depressing indeed: melting polar ice along with thermal expansion of the oceans could raise the sea level, flooding coastal cities, and many agricultural landscapes could dry out, becoming deserts. And yet, as the class studied the issue further, we learned that the news is not all bad.

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To understand the ozone layer , it would be helpful to know the different layers of the atmosphere. A lot of human activities such as gas balloons, mountain climbing, and small aircraft flights take place within this region. The stratosphere is the next layer above the troposphere stretching approximately 15 to 60 kilometers. The ozone layer sits in the lower region of the stratosphere from about kilometers above the surface of the earth.

The thickness of the ozone layer is about 3 to 5 mm, but it pretty much fluctuates depending on the season and geography. This lower region of the stratosphere containing a relatively higher concentration of ozone is called Ozonosphere. The Ozonosphere is found km 9 to 22 miles above the surface of the earth. The concentration of ozone in the ozone layer is usually under 10 parts per million while the average concentration of ozone in the atmosphere is about 0.

The thickness of the ozone layer differs as per season and geography. The highest concentrations of ozone occur at altitudes from 26 to 28 km 16 to 17 miles in the tropics and from 12 to 20 km 7 to 12 miles towards the poles. The ozone layer forms a thick layer in the stratosphere, encircling the earth, which has a large amount of ozone in it.

The ozone layer protects life on earth from strong ultraviolet radiation that comes from the sun. Ultraviolet rays are harmful rays that can drive up the risk of deadly disorders like skin cancer, cataracts and damage the immune system. Ultraviolet rays are also capable of destroying single-cell organisms, terrestrial plant life, and aquatic ecosystems. It comes as a surprise that the same UV rays from the bulk of the ozone layer.

Ozone is an extraordinary kind of oxygen composed of 3 oxygen atoms instead of the normal 2 oxygen atoms. The ozone layer normally develops when a few kinds of electrical discharge or radiation splits the 2 atoms in an oxygen O2 molecule, which then independently reunite with other types of molecules to form ozone. People began to value the importance of the ozone layer when scientists released a research finding suggesting that certain human-made chemicals known as chlorofluorocarbons managed to reach the stratosphere and depleted the ozone via a profound series of chemical reactions.

The results of this research study prompted the signing of a global treaty known as the Montreal Protocol in This treaty helped in the reduction of the production of these harmful human-made chemicals. These targeted efforts have seen the ozone layer recovering over the past years.

The thickness of the ozone layer varies immensely on any day and location. Due to relentless vertical atmospheric air circulation in both the stratosphere and troposphere, the amount of ozone layer shielding humans from strong UV rays can be lesser or greater. In addition, those residing in higher elevations are at risk of UV radiation than those at lower elevations. The Stratospheric ozone plays a big role in protecting humans from the harshness of the sun.

However, there is also a kind of ozone developed just above the ground as a result of sun rays coming into contact with pollution in the atmosphere , which is hazardous to human health. In some individuals, it can lead to complications in breathing and often takes place during the summer when pollution is rampant in cities where the air is static.

In this process, it also absorbs ultraviolet radiation that is dangerous for most living beings. UV radiation could injure or kill life on Earth. Though the absorption of UV radiation warms the stratosphere but it is important for life to flourish on planet Earth. Research scientists have anticipated the disruption of susceptible terrestrial and aquatic ecosystems due to the depletion of the ozone layer.

Ultraviolet radiation could destroy the organic matter. Plants and plankton cannot thrive, both acts as food for land and sea animals, respectively. For humans, excessive exposure to ultraviolet radiation leads to higher risks of cancer especially skin cancer and cataracts.

It is calculated that every 1 percent decrease in the ozone layer results in a percent increase in the occurrence of skin cancer. Other ill-effects of the reduction of protective ozone layer include — increase in the incidence of cataracts, sunburns and suppression of the immune system. Credible scientific studies have substantiated that the cause of ozone layer depletion is human activity, specifically, human-made chemicals that contain chlorine or bromine.

Scientists have observed a reduction in stratospheric ozone since the early s. It is found to be more prominent in Polar Regions. Ozone-Depleting Substances have been proven to be eco-friendly , very stable and non-toxic in the atmosphere below. This is why they have gained popularity over the years. However, their stability comes at a price; they are able to float and remain static high up in the stratosphere.

When up there, ODS are comfortably broken down by the strong UV light and the resultant chemical is chlorine and bromine. Chlorine and bromine are known to deplete the ozone layer at supersonic speeds. They do this by simply stripping off an atom from the ozone molecule. One chlorine molecule has the capability to break down thousands of ozone molecules.

Ozone-depleting substances have stayed and will continue to stay in the atmosphere for many years. This, essentially, implies that a lot of the ozone-depleting substances humans have allowed going into the atmosphere for the previous 90 years are still on their journey to the atmosphere, which is why they will contribute to ozone depletion.

The chief ozone-depleting substances include chlorofluorocarbons CFCs , carbon tetrachloride, hydrochlorofluorocarbons HCFCs and methyl chloroform. Halons, sometimes known as brominated fluorocarbons, also contribute mightily to ozone depletion. However, their application is greatly restricted since they are utilized in specific fire extinguishers.

The downside to halons is they are so potent that they are able to deplete the ozone layer 10 times more than ozone-depleting substances. Scientists in this age are working around the clock to develop Hydrofluorocarbons HFCs to take the place of hydrochlorofluorocarbons HCFCs and chlorofluorocarbons CFCs for use in vehicle air conditioning.

Hydrochlorofluorocarbons are powerful greenhouse gases , but they are not able to deplete ozone. Chlorofluorocarbons, on the other hand, significantly contribute to climate change, which means Hydrofluorocarbons continue to be the better alternative until safer alternatives are available. The ozone layer has been found to be affected by certain natural phenomena such as Sun-spots and stratospheric winds.

It is also believed that the major volcanic eruptions mainly El Chichon in and Mt. Pinatubo in has also contributed towards ozone depletion. The main cause for the depletion of ozone is determined as excessive release of chlorine and bromine from man-made compounds such as chlorofluorocarbons CFCs. These are categorized as ozone-depleting substances ODS. The problem with the Ozone-Depleting Substances ODS is that they are not washed back in the form of rain on the earth and in-fact remain in the atmosphere for quite a long time.

With so much stability, they are transported into the stratosphere. These gases are carried to the stratosphere layer of the atmosphere where ultraviolet radiation from the sun breaks them to release chlorine from CFCs and bromine from methyl bromide and halons. The chlorine and bromine free radicals react with the ozone molecules and destroy their molecular structure, thus depleting the ozone layer.

One chlorine atom can break more than 1, 00, molecules of ozone. Bromine atom is believed to be 40 times more destructive than chlorine molecules. It was utilized as a coolant in home appliances like freezers, refrigerators and air conditioners in both buildings and cars that were manufactured prior to This substance is usually contained in dry cleaning agents, hospital sterilants, and industrial solvents.

The substance is also utilized in foam products like mattresses and cushions and home insulation. Hydrofluorocarbons have over the years served in place of Chlorofluorocarbons. They are not as harmful as CFCs to ozone layer. Commonly utilized in industries for cold cleaning, vapor degreasing, chemical processing, adhesives and some aerosols. If the ozone layer is depleted, it means humans will be overly exposed to strong UV light. Overexposure to strong UV light causes skin cancer, cataracts, sunburns, weakening of the immune system and quick aging.

Many crop species are vulnerable to strong UV light and overexposure may well lead to minimal growth, photosynthesis and flowering. Some of the crop species vulnerable to UV light include barley, wheat, corn, oats, rice, broccoli, tomatoes, cauliflower just to name a few. Forests equally bear the brunt of ozone depletion.

Certain marine life , especially planktons, is greatly impacted by exposure to strong ultraviolet rays. In the aquatic food chain, planktons appear high up. If planktons decrease in number due to ozone layer destruction, the marine food chain would be disrupted in many ways. Also, overexposure of sun rays could reduce the fortunes of fishers. On top of that, certain species of marine life have been greatly affected by overexposure to ultraviolet radiation at their early stage.

Materials like plastics, wood, fabrics, rubber are massively degraded by too much ultraviolet radiation. Pesticides are great chemicals to rid your farm of pests and weeds, but they contribute enormously to ozone layer depletion.

The surefire solution to get rid of pests and weeds is to apply natural methods. Just weed your farm manually and use alternative eco-friendly chemicals to alleviate pests. The easiest technique to minimize ozone depletion is to limit the number of vehicles on the road. These vehicles emit a lot of greenhouse gases that eventually form smog , a catalyst in the depletion of the ozone layer.

Most household cleaning products are loaded with harsh chemicals that find way to the atmosphere, eventually contributing to the degradation of the ozone layer. Use natural and environmentally friendly cleaning products to arrest this situation. However, the protocol never covered nitrous oxide, which is a known harmful chemical that can destroy the ozone layer.

Nitrous oxide is still in use today. Governments must take action now and outlaw nitrous oxide use to reduce the rate of ozone depletion. Chlorofluorocarbons CFCs 2. Hydrofluorocarbons HCFCs 3. Halons 4. Carbon Tetrachloride 5. Damage to Human Health 2.

The Devastation to the Environment 3.

Climate Change

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Ozone depletion consists of two related events observed since the late s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere the ozone layer , and a much larger springtime decrease in stratospheric ozone around Earth's polar regions. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events. The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants , solvents , propellants , and foam- blowing agents chlorofluorocarbons CFCs , HCFCs, halons , referred to as ozone-depleting substances ODS. These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. Ozone depletion and the ozone hole have generated worldwide concern over increased cancer risks and other negative effects. The ozone layer prevents most harmful wavelengths of ultraviolet UV light from passing through the Earth's atmosphere.

Emissions were increasing rapidly until the s. Since then the world has achieved rapid progress: the near-elimination of ozone-depleting substances and the trend towards recovery of the ozone layer are arguably among the most successful international environmental collaborations to date. In this entry we present the data on ozone layer depletion, signs of recovery, emissions of ozone-depleting substances, international agreement and collaboration, and the consequences of ozone layer depletion. It is formed of three oxygen atoms giving it the chemical formula, O 3. This reactivity is significant in its interactions described in the entry below : the ozone layer can be depleted and broken down through its interaction with man-made compounds in the upper atmosphere.

Air Information Resource

Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. A substance is a catalyst if it serves to drive or enhance a process or reaction--without itself being consumed in the process. In these reactions, NO and C1 are not consumed as they destroy O3 because they are regenerated in the last reaction of the cycle.

To understand the ozone layer , it would be helpful to know the different layers of the atmosphere. A lot of human activities such as gas balloons, mountain climbing, and small aircraft flights take place within this region. The stratosphere is the next layer above the troposphere stretching approximately 15 to 60 kilometers. The ozone layer sits in the lower region of the stratosphere from about kilometers above the surface of the earth.


  • Efebo B. 02.05.2021 at 19:40

    The causes, mechanism and bio-effects of ozone layer depletion on humans were addressed. It is revealed that introduction of Chlorof-.

  • Lafutepa 04.05.2021 at 17:05

    Published Jul 16, Updated Jul 27,

  • Cala M. 06.05.2021 at 06:23

    Ccna study guide 6th edition pdf free download flippingbook pdf publisher crack

  • Loruhama B. 06.05.2021 at 14:18

    Scientific Assessment of Ozone Depletion:

  • Brier F. 09.05.2021 at 10:23

    April 5, Journal article Open Access.


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