Ozone Depletion

1. Ozone Depletion

2. What is the Atmosphere? All of the gases that surround Earth Mixture of mostly nitrogen and oxygen Other gases that are present in trace amounts include argon, carbon dioxide, methane and water vapor

3. Composition of the Atmosphere • Nitrogen 78% • Oxygen 21% • Other 1% • Argon, • Carbon Dioxide • Methane • Water Vapor

4. The Composition of Gases in the Atmosphere is constantly changing! • Think of any examples of gases being added or removed in the atmosphere

6. What Else is in the Atmosphere? In addition to gases, the atmosphere also contains some particulates. We call these particles atmospheric dust. • What are some materials that might be part of atmospheric dust?

7. Atmosphere also contains particulates • Particulates – aka atmospheric dust • Includes: • Pollen • Volcanic ash, smoke and ash from fires • Bacteria • Soil particles • Aerosols

8. Gravity The force that pulls everything to the earth! • Gravity causes the Earths atmosphere to be MORE dense near the Earth’s surface!So at higher elevations, the air becomes LESS dense!

9. Think…Denver, CO is a mile high city. If you were to ski in the Denver area, you might have a hard time breathing. Why?

10. Denver, CO is a mile high city. If you were to ski in the Denver area, you might have a hard time breathing because… 1. You’re exercising and need more oxygen 2. However, the air is less dense which means it has less oxygen!

11. Think…Why do planes fly at higher altitudes where the air is less dense?

12. Planes fly at higher altitudes where the air is less dense because…At higher altitudes, the air is less dense, so there is less drag and therefore higher fuel efficiency.

13. Gravity How does gravity affect the layering of the atmosphere? Denser materials are closer to the earth. Denser layers of the atmosphere will be closer to the earth.

14. Layers of the atmosphere?

15. Troposphere • Nearest Earth’s surface • About 18 km high • Densest layer • Within this layer temperature decreases as altitude increases

16. Stratosphere • Above Troposphere • 18 km to 50 km • Contains ozone layer • Ozone* molecules absorb UV energy from the sun and heat up this layer • Therefore, temperature Increases as altitude increases *Ozone O3 reduce UV radiation that reaches the Earth

17. Mesosphere • Above the Stratosphere • 50 km to 80 km high • Coldest layer • Temperature decreases as altitude increases

18. Thermosphere • Farthest from Earths surface • 80km-550 km • N2 and O2 absorb solar radiation • Temperatures of 2000 C • Molecules in this layer absorb harmful x-rays and gamma rays from the sun, causing atoms to become electrically charged ions • Also called the ionization layer • Aurora borealis- Solar lights

19. Review – layers of atmosphere • Troposphere – layer closest to surface; gas particles most dense here • Stratosphere – OZONE LAYER HERE! • Mesosphere – less dense that stratosphere – coldest layer • Thermosphere – farthest from surface; least dense and hottest; absorbs x-rays and gamma rays from sun

20. What happens to temp in each layer? • Troposphere – as alt increases, temp decreases • Stratosphere – as alt increases, temp increases • mesosphere – as alt increases, temp decreases • Thermosphere – as alt increases, temp increases

21. Activity Directions: • Watch the video clip of the atmosphere at one of the computers. (link on my teacher page) • Complete the 2 worksheets- colored pencils up front • When you have finished, take an article to read • Return to your seat and read the article

24. Interpret this Graph • What happens as to the temperature as you rise through the… -Troposphere? -Stratosphere? -Mesosphere? -Thermosphere?

25. What layer includes the Ozone layer?  The Stratosphere Ozone* is a molecule made of three oxygen atoms it can be found near the ground where its bad, or up in atmosphere where its good…hence, good up high, bad nearby *Ozone O3 reduce UV radiation that reaches the Earth

26. What does the ozone layer do? • The ozone layer absorbs UV radiation from the Sun. • UV radiation is part of the electromagnetic spectrum. • Exposure to UV radiation can lead to skin cancer

27. So…Why is a hole in the ozone layer or ozone depletion bad??? • Too much UV radiation might cause skin cancers

28. What is the ozone layer and where is it found? • The ozone layer is the layer of the atmosphere at an altitude of 15 to 40 km • Located in the stratosphere

29. What is Ozone? • Ozoneis a molecule made of three oxygen atoms • What is the function of the ozone layer? • In the stratosphere, ozone absorbs ultraviolet solar radiation.

30. ozone Ozone in the Troposphere Ozone in the Stratosphere Ozone is good up high, bad nearby! It forms the ozone layer, which protects us from harmful UV radiation • In the troposphere, it is a pollutant, formed by the reaction of NOx, and VOCs with sunlight • Ozone is bad nearby, but good up high

31. So…What’s the issue with the ozone layer? • These satellite images below show the growth of the ozone hole (blue, then purple, then red) over the past two decades.

32. How is ozone depleted?

33. The chemical reaction that destroys ozone.

34. Chemical equationfor this process…

35. How Does the Ozone Hole Form?

36. If ozone is also being produced as air pollution, why does this ozone not repair the ozone hole in the stratosphere? • Ozone is very chemically reactive. It can chemically burn your lungs (Good up high…bad near by) • Ozone produced by pollution breaks down or combines with other substances in the troposphere long before it can reach the stratosphere to replace ozone that is being destroyed

39. What are the effects of thinning ozone layer on humans? • As the amount of ozone decreases, more UV light is able to pass through the atmosphere and reach Earth’s surface. • UV light damages DNA • Exposure to UV light makes the body more susceptible to skin cancer, and may cause other damaging effects to the human body.

46. What have we done to protect the ozone layer?

48. 2007 was the 20th anniversary of the Montreal Protocol: • "The Montreal Protocol has been a resounding success," said Richard Stolarski, a speaker at the symposium from NASA's Goddard Space Flight Center, Greenbelt, Md. "The effect can be seen in the leveling off of chlorine compounds in the atmosphere and the beginning of their decline." • Since the Montreal Protocol was signed on Sept. 16, 1987, more than 100 nations have agreed to limit the production and release of compounds, notably human-produced chlorofluorocarbons, known as CFCs. CFCs and a list of other compounds are known to degrade the layer of ozone in the stratosphere that shields life from the sun's ultraviolet radiation. That process gives rise to the ozone hole above Antarctica.

49. Other forms of Pollution…. NOISE!!! • A sound of any kind is called a noise. • Some noises are unnecessary and can cause noise pollution. • Health problems that can be caused by noise pollution include loss of hearing, high blood pressure, and stress. • Noise can also cause loss of sleep, which may lead decreased productivity at work and in the classroom.