Aim: Learn about causes and effects of ozone depletionNew words: ozone, ozone layer, troposphere, stratosphere, U.V. (ultraviolet radiation)

Do Now: List 3 things you already know about ozone layer or ozone depletion

What is ozone?

• Molecules of ozone consist of three oxygen atoms.• Ozone at ground level is a pollutant.• Ozone layer at stratosphere serves an important function.

Aim: Learn about causes and effects of ozone depletion

What is ozone?

“Smog” Ozone

Ozone Amount

“Good Ozone”

“Bad Ozone”

Aim: Learn about causes of ozone depletion35

30

25

20

15

10

5

50 10 15 20 25

Stratospheric Ozone(The Ozone Layer)

Tropospheric OzoneAlti

tude

(K

ilom

eter

s)

1. In which layer does ozone layer occur?

2. At what altitude is the ozone layer located?

3. Where else is ozone present in the atmosphere?

Stratosphere

At troposphere, between the ground and 5 kilometers high

Between 20 to 30 kilometers high

4. What sort of radiations is made sunlight of?

5. What is UV (ultraviolet radiation)?

Aim: Learn about causes of ozone depletion

Sunlightspectrum

Mostly UV, visible light, infrared radiation, microwaves

UV is a high energy radiation present in sunlight radiation

Formation of O3 in the AtmosphereAim: Learn about causes of ozone depletion

Aim: Learn about causes of ozone depletion

What is ozone?

Ozone molecule is made of three oxygen atoms

UV radiation splits molecular oxygen (02) into atomic oxygen (O)Reactive atomic oxygen combines with molecular oxygen to form ozone (O3)

UV energy is absorb by oxygen molecules and ozone molecule and causes both to split into molecular or atomic oxygen

6. What an ozone molecule is made out of?

7. Explain how ozone molecules are formed in the atmosphere

8. How is the UV energy used up?

Every time even a small amount of the ozone layer is lost, more ultraviolet light from the sun can reach the Earth.

Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. UV-B increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer.

The increased cancer levels caused by exposure to this ultraviolet light could be enormous. The EPA estimates that 60 million Americans born by the year 2075 will get skin cancer because of ozone depletion. About one million of these people will die.

In addition to cancer, some research shows that a decreased ozone layer will increase rates of malaria and other infectious diseases. According to the EPA, 17 million more cases of cataracts can also be expected.

The environment will also be negatively affected by ozone depletion. The life cycles of plants will change, disrupting the food chain. Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive. If that happened, it would mean that all of the other animals that are above plankton in the food chain would also die out. Other ecosystems such as forests and deserts will also be harmed.

Aim: Learn about the effects of ozone depletion

9. What are the effects of UV on living things?

Every time even a small amount of the ozone layer is lost, more ultraviolet light from the sun can reach the Earth.

Every time 1% of the ozone layer is depleted, 2% more UV-B is able to reach the surface of the planet. UV-B increase is one of the most harmful consequences of ozone depletion because it can cause skin cancer.

The increased cancer levels caused by exposure to this ultraviolet light could be enormous. The EPA estimates that 60 million Americans born by the year 2075 will get skin cancer because of ozone depletion. About one million of these people will die.

In addition to cancer, some research shows that a decreased ozone layer will increase rates of malaria and other infectious diseases. According to the EPA, 17 million more cases of cataracts can also be expected.

The environment will also be negatively affected by ozone depletion. The life cycles of plants will change, disrupting the food chain. Oceans will be hit hard as well. The most basic microscopic organisms such as plankton may not be able to survive. If that happened, it would mean that all of the other animals that are above plankton in the food chain would also die out. Other ecosystems such as forests and deserts will also be harmed.

Aim: Learn about the effects of ozone depletion

9. What are the effects of UV on living things?

•Skin cancer•Increase rates of malaria and other infectious diseases•Cataracts•Microscopic organisms (plankton) die. •Disruption of food chain

What is the effect of being overexposed to UV radiation?

• Sunburn

• Cancer

• Damage eyes & cataracts

• Decrease organisms’ resistance to disease

• Damage tissue in plant leaves and phytoplankton in the oceans

• Disrupt food chains in the ocean

Aim: Learn about the effects of ozone depletion

In the absence of an ozone layer, life could only evolve under water

Aim: Learn about the effects of ozone depletion

O3 “absorbs” UV-B radiation and “uses up” its energy, converting it to harmless heat: UV + O3 O + O2

The ozone layer does not really “shield” us or “reflect” harmful UV radiation, but rather “uses up” UV energy before it can reach earth

Aim: How Does Stratospheric Ozone Protect US?

What is the role of Ozone Layer ?

Aim: How Does Stratospheric Ozone Protect US?

What is the role of Ozone Layer ?

Aim: How Does Stratospheric Ozone Protect US?

9. What is the role of the ozone layer? How does the ozone layer or ozone shield protect us?

The ozone layer does not really “shield” us or “reflect” harmful UV radiation.

The ozone layer protect us from UV by absorbing UV energy before it can reach the ground

Aim: How Did the Ozone Layer Change Over Time?

10. What is the trend of the ozone layer from 1980 to 2000?Ozone layer decreased (depleted) from 1980 to 1996.Then it increased from 1998 to 2000

Monthly average ozone levels over Antarctica, 1956-1994, for the month of October

Aim: How Did the Ozone Layer Change Over Time?

Aim: How Did the Ozone Layer Change Over Time?

Beginning in the 1970s, scientists found evidence from satellite data that the ozone layer was in trouble.

There are two holes in the ozone layer, one over Antartica, the other appeared over the Artic

Aim: How Did the Ozone Layer Change Over Time?

The production and emission of CFCs, ChloroFluoroCarbons, is by far the leading cause of ozone depletion.Many countries have called for the end of CFC production because only a few produce the chemical. However, those industries that douse CFCs do not want to discontinue usage of this highly valuable industrial chemical.

CFCs are used in industry in a variety of ways and have been amazingly useful in many products. Discovered in the 1930s by American chemist Thomas Midgley, CFCs came to be used in refrigerators, home insulation, plastic foam, and throwaway food containers.

Only later did people realize the disaster CFCs caused in the stratosphere. There, the chlorine atom is removed from the CFC and attracts one of the three oxygen atoms in the ozone molecule. The process continues, and a single chlorine atom can destroy over 100,000 molecules of ozone.

In 1974, Sherwood Rowland and Mario Molina followed the path of CFCs. Their research proved that CFCs were entering the atmosphere, and they concluded that 99% of all CFC molecules would end up in the stratosphere.Only in 1984, when the ozone layer hole was discovered over Antarctica, was the proof truly conclusive. At that point, it was hard to question the destructive capabilities of CFCs.Even if CFCs were banned, problems would remain. There would still be no way to remove the CFCs that are now present in the environment. Clearly though, something must be done to limit this international problem in the future.

Aim: What causes ozone depletion?

Aim: What causes ozone depletion?

11. Which gasses damage the ozone layer?

12. What products are there that contain or use CFC´s ?

CFCs, (ChloroFluorCarbons)

• Propellants in aerosol cans• Coolant in refrigerator,• Freezers• Air conditioners• Production of plastic foams

The main cause of ozone depletion is the release of gases CFC’s into the atmosphere

Aim: What causes ozone depletion?

It can take 5-15 years for a CFC molecule to migrate to the stratosphere.

Aim: What causes ozone depletion?

Aim: How has the production of CFC’s changed in the last years?

CFC’s production increased from 1950 to 1987. After the Montreal protocol, CFC’s production decreased steadily.

13. How has the production of CFC’s evolved in the last years?

15. What can you do to make a difference?

Avoid using and buying products that might be made with CFCs

For example: use a reusable cup instead of a plastic foam one.

Have home and car air conditioners checked for leaks

Use air conditioners only if needed for health or safety reasons.

When serving your car, take it to a station that can recycle the air conditioning coolant

Aim: What can you do to solve the problem?

A World with no Ozone LayerNewspaper cartoon from 1986

Environment problem

Causes Molecules Effects Solutions

Ozone

Depletion

CFCs emissions from

1. Propellants in aerosol cans

2. Coolant in refrigerator & freezers

3. Air conditioners

4. Production of plastic foams

CFCsSunburn

Cancer

Damage eyes

Decrease organisms’ resistance to disease

Damage tissue in plant leaves and phytoplankton in the oceans

Disrupt food chains in the ocean

Laws & Legislation prohibiting CFCs products

Avoid using and buying products that might be made with CFCs

Reusable cup instead of a plastic foam one.

Have home and car air conditioners checked for leaks

1) In the early 1980's, scientists discovered holes in the ozone shield surrounding Earth. State one negative effect this environmental change could have on humans.

•More UV rays reach the Earth, increasing incidence of sunburnMore UV rays reach the Earth, increasing incidence of sunburn

•Increased incidence of skin cancers and/or cataracts Increased incidence of skin cancers and/or cataracts

•Decreased humans’ resistance to diseaseDecreased humans’ resistance to disease

3. Write a paragraph to explain why the amount of UV (Ultraviolet radiation) reaching the surface of the Earth is increasing, and describe its effects on the living things

The increase in UV light reaching the surface of Earth is due to The increase in UV light reaching the surface of Earth is due to the thinning of the ozone layer in the upper atmosphere. the thinning of the ozone layer in the upper atmosphere.

The ozone is being destroyed due to certain gases manufacture The ozone is being destroyed due to certain gases manufacture and use, including CFCs. The loss has been most severe over the and use, including CFCs. The loss has been most severe over the South Polar region. South Polar region.

If plankton in the oceans below these “holes” is harmed or killed If plankton in the oceans below these “holes” is harmed or killed by the increase in UV light, entire food chains will be disrupted by the increase in UV light, entire food chains will be disrupted because the plankton are the organisms that start all of the because the plankton are the organisms that start all of the ocean food chains. Without them, there would be no food for ocean food chains. Without them, there would be no food for larger organisms.larger organisms.

Reducing funds for public transportation would result in Reducing funds for public transportation would result in a) More air pollution, since more car would be used for a) More air pollution, since more car would be used for

commutingcommutingb) Increasing global warming, since more CO2 is released b) Increasing global warming, since more CO2 is released in the atmospherein the atmosphere

2) State one environmental impact of reduced funding for public transportation (trains, city buses, school buses, etc.) on future generations. Explain your answer.