1. Characteristics of the Atmosphere

2. Composition of Atmosphere
Made up mostly of Nitrogen (N)
Oxygen makes up a little more than 20%

3. Atmospheric Pressure
Gravity pulls molecules towards Earth
Creates air pressure
Atmosphere is held by gravity
As altitude increases, air pressure decreases

4. Atmospheric Layers
-sphere: ball; each layer surrounds Earth like a hollow ball
-tropo: turning or change; gases turn and mix
- strato: layer; gases are layered
- meso: middle
- thermo: heat; temps are highest here

5. Layers of the Atmosphere
Troposphere
Stratosphere
Mesosphere
The layer in which we live
Lies next to Earth’s surface
Weather occurs here
As altitude increases, temp decreases
Home of the Ozone layer
As altitude increases, temp increases
Middle layer
Coldest layer

6. Layers of the Atmosphere cont’d
Edge of the Atmosphere
Uppermost layer
As altitude increases, temp increases also
1,000˚C, but doesn’t feel hot!
Not it’s own layer, but located in the Upper Mesosphere and Lower Thermosphere
Contains electrically charged particles called ions
Home of the Auroras
Nitrogen and Oxygen absorb harmful solar energy
Thermosphere
Ionosphere

8. Check Up
Write each question and answer (in complete sentences) in your notes.
List the layers of the atmosphere, starting with the one closest to Earth.
Why does air pressure decrease as altitude increases?
How can the thermosphere have high temperatures but not feel hot?
What two gases make up most of the atmosphere?
Explain how density affects the transfer of thermal energy in the air.
If you finish early, get an Earth science book and begin reading the section assigned for homework.

9. Global Winds and Local Winds

10. Why Air Moves Equator and Poles Cold air sinks
Creates a high pressure around the poles
Cold air then flows toward the equator

11. Pressure Belts
Coriolis Effect
Every 30° latitude
Bands of high and low pressure
Curving of path of currents due to Earth’s rotation

13. Global Winds Polar Easterlies Westerlies
Wind belts that extend from the poles to 60° latitude
Wind belts found between 30° and 60° latitude

14. Trade Winds
Doldrums
Winds that blow from 30° to almost the equator
Where trade winds meet around the equator

15. Horse Latitudes
Jet Streams
At about 30° North and 30° South
Sinking air creates an area of high pressure
Narrow belts of high- speed winds
Blow in the upper Troposphere and lower Stratosphere

17. Local Winds Generally move short distances Can blow from any direction
Mountain and Valley Breezes
Sea and Land Breezes
Generally move short distances
Can blow from any direction
Caused by an area’s geography
Affected by temperature
Local Winds

18. Sea Breeze
Land Breeze
wind that blows from an ocean or lake to land
land warms faster than water
happens during day
winds that blow from land to a body of water
land cools faster than water
happens at night

20. Air Pollution

21. Primary Pollutants
Secondary Pollutants
Pollutants put directly into the air by human or natural activity
When primary pollutants react with other primary pollutants or natural substances (water vapor)

22. Industrial Air Pollution
Indoor Air Pollution
Burning of fossil fuels
Ex: Power plants
Sometimes can be more polluted than outside air

24. Ozone
Ozone Hole
Layer is thinning over the Arctic and Antarctic regions
Allows more UV radiation to reach Earth’s surface
CFCs cause Ozone depletion
CFCs remain active for years

25. Human Effects from Air Pollution
Short-term effects
Long-term effects
Coughing
Sneezing
Headaches
Eye irritation
Lung cancer

26. Clean Air Act
EPA
Requires many industries to use pollution-control devices
Sets air quality standards