1. Human activities affect the atmosphere.

2. The Ozone Layer: A Review
90% of all ozone is in the stratosphere
10% of all ozone is in the troposphere
Ozone is extremely important because it is the only gas that absorbs UV radiation from the sun and protects the Earth from its damaging effects.

3. Human activities cause air pollution, increase greenhouse gases, and produce chemicals that destroy the ozone layer.
*Think about when someone burns toast at home. Can you smell it sometimes, even if you’re in a different room? Why?
*Everyone that breathes in that air breathes in the smoke from the burnt toast. Is this air pollution?
*When we are outdoors, the wind blows air pollution just like the fan does at home.
*Can you smell, see or feel ALL types of air pollution?
MOST pollution leaves the air or becomes thin enough to be harmless over time.

4. Human Sources of Pollution
Smog
Transportation and Industry
Fossil Fuels
Farming
Acid Rain

5. Smog The combination of smoke, fog and chemicals
Sunlight causes fumes from fossil fuels to react chemically. The reaction forms new pollutants (like ozone) and creates smog.
Smog causes breathing issues by irritating the lungs.
Top World Cities with Smog:
Zabol Iran, Riyadh Saudi Arabia, Xingtai China,
Top US Cities with Smog
El Centro Calif., Washington D.C. - Baltimore - Northern Virgina, Dallas - Fort Worth, Texas

6. https://ed.ted.com/lessons/the-science-of-smog-kim-preshoff
Smog

7. Fossil Fuels
Fuels formed from prehistoric organisms that are burned for energy
Examples: Coal, Gasoline and Oil
Using less Fossil Fuels is the best way to improve air quality because the burning of fossil fuels is THE major cause of air pollution.
Fossil Fuels release large amounts of CO2 and other gases in the air.

9. Acid Rain
Acid Rain is when the gases from burning fossil fuels mix with water vapor.
The acids mix with cloud droplets or ice crystals that eventually fall to Earth’s surface as precipitation.
It is harmful to both living and non living things.

10. Natural Sources of Pollutions
Pollutants: dust, pollen, radon mold spores and salt
Natural Events release pollutants such as:
Forest Fires
Volcanic Eruptions
Plant Pollen

11. Environmental Protection Agency
The Environmental Protection Agency (EPA) is an agency of the US federal government created for the purpose of protecting human health and the environment.
Benefits of the EPA:
Cleaner Air- regulations have been placed on factories smokestacks from releasing harmful pollutants into the air. Lead has been removed from gasoline and paint.
Cleaner Water- banned dumping sewage and other pollutants into steams, lakes and rivers
Pesticides- removed the use of DDT ( a cancer causing agent.
Environmental Waste- banned disposing of hazardous chemical waste like ordinary trash
Climate – limiting carbon pollution from power plants which increase greenhouse gases.