Atmospheric Pollution

This is a PPT on Atmospheric Pollution. Here it decribes the 3 main types of Atmospheric Pollution: 1.Acid Rain, 2.Ozone Depletion, 3.Green House Effect.

1. ATMOSPHERIC POLLUTION Done By: Gourisankaran.P

2. What is pollution? The word pollution was derived from the Latin word ‘ pollutus’ meaning ‘ to make unclean ‘. Pollution is the introduction of contaminants into the natural environment that causes adverse change.

3. Atmospheric pollution/ air pollution Atmospheric pollution is the introduction of chemicals, particulates, biological materials, or other harmful materials into the Earth’s atmosphere, possibly causing disease, death to humans, damage to other organisms such as food crops, or to the environment.

4. Causes of air pollution The conditions of air are made unclean due to introduction of foreign elements from : 1. Natural Sources 2. Man made sources

5. Natural Sources Dust from natural sources, usually large areas of land with few or no vegetation Methane, emitted by the digestion of food by animals, for example cattle Smoke and carbon monoxide from wildfires Volcanic activity, which produces sulfur, chlorine, and ash particulates

6. Man made sources Mobile Sources include smoke from motor vehicles, marine vessels, and aircraft. Fumes from paint, hair spray, varnish, aerosol sprays and other solvents Waste deposition in landfills, which generate methane. Sources include smoke stacks of power plants, etc.

7. TYPES OF Atmospheric POLLUTION Atmospheric Pollution is mainly of 3 types. They are:- Acid Rain Green House Effect Ozone Depletion

8. 1.Acid RAIN Acid Rain is the Precipitation that has a pH level less than that of natural rainwater(which is about 5.6 due to dissolved carbon dioxide). It is formed when sulphur dioxides and nitrogen oxides combine with water vapour and precipitate as sulphuric acid or nitric acid in rain, snow or fog.

9. EFFeCTS OF ACID RAIN Lakes are damaged by acid rain. Fish die off, and that removes the main source of food for birds. Acid rain can kill fish even before they are born when the eggs are laid and come into contact with the acid. When the acid level in a lake is lower, the fish can become sick, suffer stunted growth and lose the ability to reproduce. Birds can die from eating toxic fish and insects.

10. Acid rain can be extremely destructive for trees also. The needles and leaves of trees turn brown and fall off. Trees can also suffer from stunted growth; and have damaged bark and leaves, which makes them vulnerable to weather, disease, and insects.

11. Acid rain dissolves the stonework and mortar of buildings(especially those made of sandstone and limestone). It also accelerates weathering in metal and stone structures. E.g. Parthenon in Athens in Greece, Taj Mahal in Agra in India. It increases acidity in soil. It leeches nutrients from soil, slowing plant growth and adversely poisoning plants. It also causes brain damage, kidney problems, skin problems and Alzheimer’s in humans.

12. 2. Green House effect The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface, energy is transferred to the surface and the lower atmosphere. As a result, the temperature there is higher than it would be if direct heating by solar radiation were the only warming mechanism.

13. Impact of green house EFFECT:- Faster warming of oceans and catastrophic rising of the sea level. Polar ice caps are melting. Flooding of agricultural lowlands Extreme Climatic Change – As sea surface temperature increases, this provides optimum conditions for storm formation, increasing the frequency and intensity of natural disasters such as hurricanes.

14. Prevention methods of the Green House Effect: Reduce, Reuse, Recycle Buying products with minimal packaging will help to reduce waste. By recycling half of your household waste, you can save 2,400 pounds of carbon dioxide annually. Plant a Tree           If you have the means to plant a tree, start digging. Trees absorb carbon dioxide and give off oxygen. A single tree will absorb approximately one ton of carbon dioxide during its lifetime. Buy Energy-Efficient Products Home appliances now come in a range of energy-efficient models, and compact florescent bulbs are designed to provide more natural-looking light while using far less energy than standard light bulbs.

15. Use Less Heat and Air Conditioning Adding insulation to your walls and installing weather stripping or caulking around doors and windows can lower your heating costs more than 25 percent, by reducing the amount of energy you need to heat and cool your home. Use Less Hot Water Set your water heater at 120 degrees to save energy, and wrap it in an insulating blanket if it is more than 15 years old. Buy low-flow showerheads to save hot water and about 350 pounds of carbon dioxide yearly. Wash your clothes in warm or cold water to reduce your use of hot water and the energy required to produce it. That change alone can save at least 500 pounds of carbon dioxide annually in most households.

16. 3. Ozone layer depletion The Ozone Layer The ozone layer sits in the stratosphere approximately 25km above the Earth. It is made up of ozone gases that act like a blanket to stop too much UV radiation from the sun entering the atmosphere. The Ozone layer prevents the harmful UV radiation entering the Earth, which is vital because too much of these UV rays can cause cancer, cataracts and DNA damage. As UV radiation hits the Ozone layer the ozone gas absorbs the radiation and turns it into oxygen. Small amounts of ozone are constantly being made by the action of sunlight on oxygen. At the same time, ozone is being broken down by natural and unnatural processes that lead to ozone depletion.

17. If this process is greater than the production of ozone then the ozone layer becomes thinner and less effective . Ozone depletion occurs when the natural balance between production and destruction of stratospheric ozone is tipped in favour of destruction. As of now there is a huge hole in the Ozone Layer above Antarctica.

18. Effects of ozone layer depletion An increase in UV radiation has been linked to an increase in skin cancer which effects fair skinned individuals who are at a greater risk than darker skinned people. Scientists have proven that a 1% depletion in ozone causes a 5% increase in cases of skin cancer, the depletion rate has been 6% since 1970 and therefore the number of cancer cases has increased rapidly. UV radiation has also increased the number of cases of cataracts, which affects people’s vision. Immunity to diseases has also been effected due to the increase in UV radiation entering the atmosphere. The depletion of ozone and increase in UV rays can also lead to DNA damage, which can be catastrophic.

19. Solutions to ozone layer depletion The ozone hole is here to stay for about 50 years before the ozone levels will start to return to their normal levels. Any ozone that we could artificially add would most likely be destroyed and would not help our problem in the long run. A different approach is to destroy the CFC's when they are in the troposphere with high-powered infrared lasers located on mountainsides. Another possible plan is to dump about 50,000 tons of ethane or propane into the Antarctic stratosphere each spring. The chemicals would transform active ozone-depleting chlorine into non-ozone depleting hydrochloride. However, there are no official plans to try to fix the ozone hole in the Antarctic because we don't know enough about stratospheric mechanics to do so. By trying to fix the problem we might make it worse.

20. Done By: Gourisankaran P Class: 11 A