ozone layer depletion


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ozone layer depletion

  1. 1. Ozone layer depletion Created by:- Smriti Aggarwal Rajat sejwal Kajal Makkar Mallika Komal
  2. 2. From this we’ll understand the following;- 1. what is ozone layer, where does it occur and why is it important? 2. The difference between good and bad ozone 3. effects of ozone layer 4. impact of it
  3. 3. Ozone layer Ozone (O3) is a highly-reactive from of oxygen. Unlike oxygen (O2), ozone has a strong scent and is blue in color. Ozone exists within both the tropospheric and stratospheric zones of the Earth’s atmosphere. In the stratosphere the ozone layer is an essential protector of life on earth as it absorbs harmful UV radiation before it reaches the earth.
  4. 4. Where is it found??? Ozone is trioxygen (O3) Ozone is found in both the troposphere (lower atmosphere) and the stratosphere In the stratosphere the ozone forms a “layer”, this layer is important as it protects us from UV radiation – ozone is responsible for filtering a very high percentage of UV radiation
  5. 5. Good and bad ozone The ozone is the stratosphere is GOOD ozone as it filters the UV radiation Ground level tropospheric ozone is BAD ozone as it can exacerbate asthma and cause other respiratory and associated health problems When you investigate urban microclimates and pollution you will study ground level ozone
  6. 6. Ozone depletion Ozone is continually created and destroyed within the stratosphere (O+O2=O3+O=2O2+O=O3 etc.) The total amount of ozone in the stratosphere is determined by the balance between photochemical production and recombination This good ozone in the stratosphere can be destroyed by ozone depleting substances (ODS) ODS include chlorofluorocarbons (CFCs), hydro- chlorofluorocarbons (HCFCs) and halons – these have anthropogenic sources such as coolants in air conditioning systems and propellants in aerosol sprays. Whilst the source of much of the worlds ODS has been removed (see Montreal Protocol below) it is worth remembering that 1 chlorine atom can destroy 100,000 molecules of ozone and these chlorine atoms stay in the stratosphere a long time.
  7. 7. The ozone hole Whilst CFCs and other ODS led to a depleltion in global stratospheric ozone levels this was not distributed evenly. In the tropics no noticeable declines have been recorded, whilst in middle latitudes declines of between 3 and 6% have been measured. Reactions that take place in polar stratospheric clouds speed up the depletion of ozone – thus levels of depletion of Antarctica (where such clouds are common) were much faster than elsewhere. This is where the concept of an “ozone hole” first emegred
  8. 8. Impacts of ozone depletion Less ozone = more UV penetration into the troposphere and lower atmosphere The most serious human impacts are skin cancer and cataracts Increased tropospheric UV radiation can lead to greater levels of BAD tropospheric ozone High levels of UV can also affect rice and plankton growth
  9. 9. effects Ozone depletion causes increases in UV rays' effects on aquatic ecosystems by: 1. decreasing the abundance of phytoplankton – affects the food stock for fishes and the absorption of CO2 2. decreasing the diversity of aquatic organisms – reduces food stock and also destroys several fish and amphibians
  10. 10. Damage to plant cell DNA molecules - makes plants more susceptible to pathogens and pests Reductions in photosynthetic capacity in the plant - results in slower growth and smaller leaves Causes mutations in mammalian cells and destroys membranes
  11. 11. Effects on humans Skin cancer Premature aging (photo aging) of the skin (different from normal chronological aging) Cataracts and eye disorders (corneal sunburn and blindness) Immune system damage
  12. 12. Solutions There are many possible solutions to this problem, but it wholly relies on us, humans.. The following are the soltuions for decreasing the ozone hole in the atmosphere:- Firstly the consumption all the cfcs should be stopped. Companies should be held responsible for the disater they are causing in the environment And we should use the 3rs…. Which are reuse , recycle, reduce initiative… so that the next generation doesnot have to go through problems made by us. And the use of cfcs should be ban