Ozone depletion presentation Mr.P.R.Tambe

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Published on March 11, 2014

Author: PRTAMBE

Source: slideshare.net

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Ozone depletion presentation Mr.P.R.Tambe.B.S. Biotech/MBA mumb.

Presentation on OZONE LAYER DEPLETION

What is the ozone layer? The ozone layer is a deep layer in the stratosphere, encircling the Earth, that has large amounts of ozone in it. The layer shields the entire Earth from much of the harmful ultraviolet radiation that comes from the sun.

Where is the ozone layer ? The ozone layer lies between 10 and 50 kilometres above the Earth's surface. It is in a region of the atmosphere called the Stratosphere. The Stratosphere completely surrounds the Earth with a thickness of about 33 kilometers in most places.

Formation of the Ozone Layer One billion years ago, early aquatic organisms called blue-green algae began using energy from the Sun to split molecules of H2O and CO2 and recombine them into organic compounds and molecular oxygen (O2). This solar energyconversion process is known as photosynthesis.Some of the photosynthetically created oxygen combined with organic carbon to recreate CO2 molecules. The remaining oxygen accumulated in the atmosphere, touching off a massive ecological disaster with respect to early existing anaerobic organisms.As oxygen in the atmosphere increased, CO2 decreased. High in the atmosphere, some oxygen (O2) molecules absorbed energy from the Sun's ultraviolet (UV) rays and split to form single oxygen atoms.These atoms combined (27k jpeg) with remaining oxygen (O2) to form ozone (O3) molecules, which are very effective at absorbing UV rays.The thin layer of ozone that surrounds Earth acts as a shield, protecting the planet from irradiation by UV light.

Advantages of ozone layer  Primarily, it blocks "UV-B", which other components of the atmosphere do not touch..  Helps to mitigate temperature, so that nights are a little warmer, and days a little cooler.

Different chemicals are responsible for the destruction of the ozone layer  Topping the list : chlorofluorocarbons (CFC’s) Catalyzed by halocarbons (carbon compounds containing fluorine, chlorine, bromine and iodine) – Examples: CFCs and ClONO2 – man-made, non-toxic and inert in the troposphere – In the stratosphere are photolysed, releasing reactive chlorine atoms that catalytically destroy ozone

Ozone-Depleting Substance(s) (ODS): CFCs, HCFCs, halons, methyl bromide, carbon tetrachloride, and methyl chloroform. dangerous

Chlorine atoms from CFCs attack the ozone, taking away ozone and forming chlorine monoxide (ClO). O3 + Cl  O2 + ClO Chlorine monoxide then combines with another oxygen atom to form a new oxygen molecule and a chlorine atom. ClO + O  Cl + O2 The chlorine atom is free to destroy up to 100,000 ozone molecules

Depletion process

Effect of depletion On Human being/Animal /plants– UV-B damages DNA, which results in cancer, mutation and reduced crop yield from any Earth- surface-dwelling organism  Skin cancer  Eye damage such as cataracts  Immune system damage  Reduction in phytoplankton  Damage to the DNA in various life-forms – this has been as observed in Antarctic ice-fish that lack pigments to shield them from the ultra- violet light (they've never needed them before)  Possibly other things too that we don't know about at the moment.

Effects of UV radiation on biological organisms DNA damage…Maximum effect on small and single cell organism Impaired growth and photosynthesis ...poor crop yields Phytoplankton: ………………………...Reduced uptake of CO2 …………………………………………..mortality …………………………………………..Impaired reproductive capacity Nitrogen-fixing soil bacteria…………. Reduced, damaged Human health effects: Suppressed immune system……………..Enhanced susceptibility to infection …………………………………………..Increase risk of Cancer Dermatology (skin)……………………...Sunburn …………….………………………….....Loss of skin elasticity (Premature aging) …………….…………………………… Photosensitivity Neoplasia (cancer)……………………....Melanocytic (malignant melanoma) …………….………………………….....Squamous cell skin – cancer …………….……………………………Basal skin – cancer Still questionable if causes lip cancer or cancer of the salivary glands Oculur (Eye)….…………………….......Cataract …………….…………………………....Pterygium

DNA & UV-B  DNA absorbs UV-B radiation  Changes shape in DNA – Changes in the DNA molecule mean that enzymes cannot “read” the DNA code – Results in mutated cells or the cells die  Cells have developed the ability to repair DNA – A special enzyme arrives at the damage site – removes the damaged section of DNA – replaces it with the proper components  This makes DNA somewhat resilient to damage by UV-B

Aquatic Ecosystems

PLANTS

The influence of the UV-B radiation on plant process.

Flowering  UV-B radiation can alter both the time of flowering as well as the number of flowers in certain species.  Differences in timing of flowering may have important consequences for the availability of pollinators.  The reproductive parts of plants, such as pollen and ovules are well shielded from solar UV-B radiation.

Amphibians

UV-B Effects on Human Over exposure may: – Increase risk of non- melanoma and malignant melanoma skin cancer  Higher risks of malignant melanoma from severe sunburns – especially in childhood  Risk of malignant melanoma has increased 10%  Risk of nonmalignant melanoma has increased 26% malignant Non-malignant www.ldeo.columbia.edu/.../ lectures/ozone_health/

-Suppress immune system -Accelerate aging of skin due high exposure -Cause an outbreak of rash in fair skin

Skin Protection  Protect the skin against the solar radiation using skin creams with SPF – The greater the numerical value of the SPF the greater the protection  Use lip balm with SPF  Cover up

cornea is encountered first then the lens vitreous humor  Increases the risk of cataracts – Induces type of protein that provokes cleaving (splitting) in the lens – Leading cause of blindness – The prevalence of cataract after age 30 is doubling each decade  Causes pterygium Over Exposure to UV B….

Manifestations of… Cataracts Pterygium Cancer brought on by over exposure to UV-B

Protection  Sunglasses with 100% UV block  Wrap around sunglasses  Eye protection for children  Hats

Images of Antarctica Taken Indicate A Slow Recovery

Suggestions

What can an individual do to reduce Ozone depletion You can make a difference by these actions:  Unplug electronics from the wall when not in use  Don't use regular incandescent light bulbs  Switch to compact fluorescent light bulbs  Follow 3R Rule - Recycle, Reduce, and Reuse  Avoid heavily packaged products  Carpool, bike, or walk instead of driving alone  Plant a tree  Buy fresh produce at you local farmer's market  Use energy efficient appliances  Limit private vehicle driving  Use eco-friendly household cleaning products  Avoid using pesticides  Developing stringent regulations for rocket launches  .Banning the use of dangerous nitrous oxide

- PRESENTED by. Mr.P.R.TAMBE - MMS IV sem.

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