7/29/2019 ozone-091001135521-phpapp01 (2)

1/20

Ozone

andEarth

7/29/2019 ozone-091001135521-phpapp01 (2)

2/20

What is the Ozone?

The ozone is a layer in our atmosphere

containing three oxygen atoms.

In the upper atmosphere it filters

ultraviolet light from reaching the Earthssurface.

7/29/2019 ozone-091001135521-phpapp01 (2)

3/20

What is the Ozone?

The purpose of the ozone is to filter out

photons with shorter wavelengths of UV

light from the sun.

These UV rays are potentiallydangerous to humans when in large

doses.

7/29/2019 ozone-091001135521-phpapp01 (2)

4/20

Where is the ozone?

The ozone is found in the stratosphere.

About 10 km 50 km above the surface.

7/29/2019 ozone-091001135521-phpapp01 (2)

5/20

Physical Properties

A pale blue gas.

Slightly soluble in water.

It is diamagnetic and will resist formation

of a magnetic field.

7/29/2019 ozone-091001135521-phpapp01 (2)

6/20

Depletion

Evidence shows that high doses of

ozone, created by high doses of

pollution and UV rays, can harm lung

function. Slow steady decline of about 4%

Much Larger decrease in ozone over

polar regions

7/29/2019 ozone-091001135521-phpapp01 (2)

7/20

Depletion

Chlorofluorocarbon (CFC) compounds

are found to be the most destructive to

ozone layer.

It has become a world wide concern.

Montreal Protocol has banned the

production of CFCs and halons.

7/29/2019 ozone-091001135521-phpapp01 (2)

8/20

Ozone Hole

There is a hole that has formed over

the south pole.

During the 1980s and 1990s the hole

was seeming to get larger but the latestobservation (2007) has stated that the

hole is now the smallest it has been for

about a decade.

7/29/2019 ozone-091001135521-phpapp01 (2)

9/20

Causes

Greatest decrease in ozone has been in

the lower stratosphere.

Chlorofluorocarbons (CFCs) invented by

Thomas Midgley in the 1920s are thebiggest threat to ozone depletion.

7/29/2019 ozone-091001135521-phpapp01 (2)

10/20

Causes

CFCs were used in :

Air conditioning/cooling units

Aerosol spray propellants

Cleaning chemicals for electronicequiptment

When ozone-depleting chemicals reachstratosphere, they release chlorine

atoms that can break down tens ofthousands of ozone molecules.

7/29/2019 ozone-091001135521-phpapp01 (2)

11/20

Consequences

Decrease in ozone layer was predicted

to be 7% over a 60 year period in early

1980s

By 1985 there was reports of asubstantial hole in the ozone.

7/29/2019 ozone-091001135521-phpapp01 (2)

12/20

Consequences

Although the hole was only over

Antarctica, many believed that the holes

could come up in other areas over

continents. May speed up the process of global

warming.

Cooler stratosphere, more stratosphereclouds, more active chlorine.

7/29/2019 ozone-091001135521-phpapp01 (2)

13/20

Consequences

More UV rays leads to an increase in

skin cancer.

Also causing more cases of cataracts.

Could ruin major cash crops from

increase in UV rays

Ex: Rice

7/29/2019 ozone-091001135521-phpapp01 (2)

14/20

Public Policy

U.S.A, Canada, Sweden and Norway all

have eliminated the use of CFCs in

aerosol spray cans.

Montreal Protocol agreed to phase outall production of CFCs and halons

completely after a meeting in 1990.

7/29/2019 ozone-091001135521-phpapp01 (2)

15/20

Past and Current Events

Since the banning of CFC production

many countries around the world took

note and have become more aware of

the situation. There has been a decrease in bromine-

containing chemicals.

7/29/2019 ozone-091001135521-phpapp01 (2)

16/20

The Future

By 2015 the ozone hole is predicted to

reduce 1 out of 25 million km.

Complete recovery of the Antarctic

ozone layer will not occur until the year2050 or later.

7/29/2019 ozone-091001135521-phpapp01 (2)

17/20

Ozone Depletion

and

Global Warming Ozone depleting chemicals are alsogreenhouse gases.

The ozone depletion will lead to the

cooling of the stratosphere causing anincrease in global warming.

7/29/2019 ozone-091001135521-phpapp01 (2)

18/20

Misconceptions

CFCs are too heavy to reach the

stratosphere.

The ozone hole is an actual hole in the

ozone.

The ozone hole should be above the

sources of CFCs not over Antarctica.

7/29/2019 ozone-091001135521-phpapp01 (2)

19/20

Review

Ozone is a layer in the stratosphere that

is protecting UltraViolet light from getting

to Earths surface.

UV rays are harmful to humanspotentially leading to causes of skin

cancer and cataracts.

7/29/2019 ozone-091001135521-phpapp01 (2)

20/20

Review

The ozone depletion is caused from

chemicals known as CFCs that are

found in aerosol spray propellants.

The ozone hole is decreasing in size.

It may take up to 40 more years to fully

recuperate the hole over Antarctica.