1. The Atmosphere
Chapter 6 Notes

2. Composition of the Atmosphere
Atmosphere: a mixture of gasses that surround the Earth
Contains the oxygen you breathe and protects you from harmful rays from the sun.
Water Vapor: make up part of the atmosphere . When conditions change the water vapor can change to a liquid (rain) or solid (snow)

3. Atmospheric Pressure The atmosphere is held around Earth by gravity.
Gravity pulls gas molecules toward Earth’s surface which causes Air Pressure.
Air Pressure: the measure of the force with which air molecules push on a surface

4. Air Pressure Air pressure is strongest on Earth’s surface.
As altitude increases the pressure decreases.
The LOWER you go the HIGHER the pressure
The HIGHER you go the LOWER the pressure

5. Atmospheric Temperature
Differences in the temperature of the atmosphere result from the amount of solar energy absorbed.
Some parts contain more gases which make them absorb more solar energy
Other parts contain less gases which mean they are absorb less solar energy and are cooler.

6. Layers of the Atmosphere

8. The First Layer Troposphere Lowest layer next to Earth’s surface
Densest layer
Contains 90% of the mass of the atmosphere
The layer we live in
Gases continuously mix in this layer
Temperatures vary in this layer

9. The Second Layer Stratosphere
Gases are layered and do not mix in this layer
The air is very thin and contains little moisture
Lower stratosphere is very cold -60 degree temp. But temperatures rise as altitudes rise
This layer is the home of the ozone layer, a protective layer that soaks of ultraviolet rays from the sun.

10. stratosphere
troposphere

11. The Third Layer Mesosphere The coldest layer
Temperatures can be as low as -93 degrees Celsius at the top of the Mesosphere

12. The Fourth Layer Thermosphere
High temperatures 1000 degrees Celsius or higher
It does not feel hot. The particles are moving very fast but they are not heating up.

14. Ionosphere This occurs between the mesosphere and thermosphere.
Gas particles become electrically charged particles called ions
These ions radiate energy in the form of shimmering light called auroras

15. Atmospheric Heating
Energy from the sun is absorbed by the atmosphere, land, and water and is changed into thermal energy.

16. Thermal Energy Transfer
Thermal energy transfer is heat moving from a warmer object to a cooler object. This is known as thermal energy transfer.

17. How is Heat Transferred?
There are THREE ways heat can move.
Conduction
Convection
Radiation

18. CONVECTION
Convection is the movement that transfers heat within fluids and air (gas)
Heat is transferred by currents within the fluid or gas
Convection = VENTS (through air and liquid particles)
Convection moves in
a circular pattern

19. Convection
Example, as air is heated, it becomes less dense and rises. Cool air is denser, so it sinks. As the cool air sinks, it pushes the warm air up. The cool air is eventually heated by the Earth's surface and begins to rise again. This is called a convection current

20. Greenhouse Effect
70% of the radiation that enters the atmosphere is absorbed by the clouds or by the Earth’s surface.
The energy is converted into thermal energy.

21. Greenhouse Effect
The greenhouse effect is the process by which the gases in the atmosphere absorb thermal energy and radiate it back to the Earth.
Acts much like the glass walls and roof in a greenhouse.

22. Radiation Balance
In order for the Earth to remain livable, the amount of radiation coming into the Earth must equal the amount of thermal energy the Earth releases into space.
There must be BALANCE!!

23. Global Warming
Global warming is the gradual increase in average global temperature
Causes the icecaps to start to melt
Possible causes
Too many greenhouse gases
Human activity
People are not doing their part to keep the Earth clean and safe
Using too many Fossil Fuels!!

24. Global Winds and Local Winds
Wind: the movement of air caused by differences in air pressure (When HIGH and LOW Pressure meet)
The greater the pressure, the faster the wind moves.

25. Air Rises at the Equator and Sinks at the Poles
Differences in air pressure are caused by unequal heating of the Earth.
Equator
Poles
Receives more solar energy
Air is warmer and less dense
The air rises creating an area of low pressure
The warm air flows towards the poles
Receives the warm air, which becomes colder and denser
The cold air sinks creating an area of high pressure
The cold air then flows back towards the equator.

26. Pressure belts are found every 30º
Air travels in many large circular patterns called convection cells.
Convection cells are separated by pressure belts that include bands of high and low pressure every 30° of latitude

28. Coriolis Effect
The Coriolis effect is the apparent curving motion of winds and ocean currents due to Earth’s rotation.
Northern Hemisphere the winds traveling north curve to the east and winds traveling to the south curve to the west

30. Global Winds
The combination of convection cells found at every 30º of latitude and the Coriolis effect produces patterns of air circulation called global winds.

31. Polar Easterlies
The wind belts that extend from the poles to 60° latitude in both hemispheres are called the polar easterlies.
They are formed as the cold sinking air moves from the poles toward 60° north and 60° south latitude.
The polar easterlies are responsible for bringing cold arctic air over the United States.

32. Prevailing Westerlies
The wind belts found between 30° and 60° latitude in both hemispheres are called the westerlies.
The westerlies flow towards the poles from west to east
The westerlies are responsible for bringing moist air to the United States.

33. Trade Winds
The winds that blow from 30° latitude almost to the equator are called trade winds.
The Coriolis effect causes the trade winds to curve west in the Northern Hemisphere and east in the Southern Hemisphere
Early traders used these winds to sail from Europe to the Americas.

34. The Doldrums
The trade winds meet in an area around the equator called the doldrums.
There is very little wind because there is very low pressure.
This is why it is called the doldrums.

35. Horse Latitudes
At about 30° north and 30° south latitude, sinking air creates an area of high pressure. The winds are weak in this area called the horse latitudes.
Legend says that sailors would get stuck in this windless area. Instead of wasting drinking water they would through the horses overboard.
Most of the Earth’s deserts are located at this latitude.

37. Jet Streams: Atmospheric Conveyor Belts
Jet Streams are a narrow belt of strong winds that blow in the upper troposphere.
Can reach maximum speeds of 400km/h
Do not follow regular patterns
Important for pilots and meteorologists.

38. Local Winds
Local winds move short distances and can blow from any direction.
Shorelines or mountains can create local wind patterns

39. Sea Breeze- during the day, air over the ocean is cooler and forms an area of high pressure. The cool air flows to the land producing a sea breeze.

40. Land Breeze- at night air over the land is cooler and forms an area of high pressure. The cooler air moves toward the ocean producing a land breeze.

41. Sea and Land Breezes

43. Mountain Breeze- at night air along the mountain slopes cool
Mountain Breeze- at night air along the mountain slopes cool . This cool air moves down the slopes into the valley producing a mountain breeze.

44. Valley Breeze – during the day, the sun warms the air along the mountain slopes. This warm air rises up the mountain creating a valley breeze.

45. Air Pollution
In December 1952, one of London's dreaded "pea souper" fogs settled on the city. But this was no ordinary fog—it was thick with coal smoke and air pollution. It burned people's lungs, and the sky grew so dark that people could not see their hands in front of their faces. When the fog lifted four days later, thousands of people were dead!

46. Air Pollution
Air Pollution is the contamination of the atmosphere by the introduction of pollution from human and natural sources
Air pollution is common in many places
Must be reduced

47. Primary Pollutants
Pollutants that are put directly into the air by humans or natural activity are primary pollutants
Ex: dust, sea salt, volcanic gases and ash, smoke for forest fires, and pollen, carbon monoxide, dust, smoke, vehicle exhaust

48. Primary Pollutants

49. Secondary Pollutants
Pollutants that form when primary pollutants react with other primary pollutants or with naturally occurring substances are secondary pollutants.
Ex: ozone and smog

50. Formation of Smog
Smog forms when ozone and vehicle exhaust react with sunlight
Pollution controls have been put in effect in some places to control the amount of pollution and reduce the amount of smog.

52. Sources of human caused air pollution
Transportation is a major cause of air pollution
It causes10-20 % of the pollution in the United States
Vehicle exhaust contains nitrogen oxide which contributes to smog

53. Industrial Air Pollution
Industrial plants and electrical power plants burn fossil fuels to produce energy.
Oil refineries, chemical manufacturing plants, dry-cleaning businesses, furniture refinishers, and auto body shops all produce air pollution.

54. Indoor Air Pollution

55. Indoor Air Pollution Indoor air pollution can be reduced by
Ventilation-mixing of indoor air with outdoor air
Reduce indoor air pollution by limiting the use of chemical solvents and cleaners

56. Acid Precipitation
Precipitation such as rain, sleet, or snow that contains acids from air pollution is called acid precipitation.
The burning of fossil fuels releases sulfur dioxide and nitrogen oxide into the atmosphere.
They combine with water in the atmosphere to form sulfuric acid and nitric acid.

57. Acid Precipitation and Plants
Soil naturally has acid.
Acid precipitation can cause the soil acidity to increase
This is called acidification.
When acidification occurs
Some nutrients are dissolved
Aluminum and toxic metals are released and absorbed by the roots of plants

58. The Effects of Acid Precipitation on Forests
Eastern Europe :Poland
Forests have been severely damaged by acid precipitation

59. Acid Precipitation and Aquatic Ecosystems
If the amount of acid increases in the water then the plants, fish, and other organisms may die.
A rapid change in a body of water’s acidity is called acid shock.
Some communities use powered lime a base to reduce the amount of acid in the water.

60. The Ozone Hole
1985 scientists reported that the ozone layer over Antarctic regions was thinning.
Chemicals called CFC were causing the ozone to break down into oxygen

61. The Ozone Hole 1987 action was taken to solve the ozone problem
A ban of all CFC chemicals was created
CFC alternatives were developed
CFC chemicals take 60 to 120 years to quit working. Therefore even with the ban CFC’s used 30 years ago are still harming the ozone now!!!

62. Air Pollution and Human Health
Short Term Effects
Long Term Effects
Headache
Nausea
Irritation to eyes, nose, and throat
Coughing
Upper respiratory infection
Worsening of asthma and emphysema
Emphysema
Lung cancer
Permanent lung damage
Heart disease

63. Cleaning up air pollution
1970 the United States Clean Air Act was passed by Congress.
This act gives the Environmental Protection Agency the authority to control the amount of pollutants that can be released from any source.
The EPA checks air quality.
The Clean Air Act was strengthened in 1990.

64. Air Pollution from Industry
The Clean Air Act requires factories to use scrubbers.
A scrubber is a device that is used to remove some pollutants before they are released by smokestacks.

65. The Allowance Trading System
The Allowance Trading System – the EPA gives allowances for the amount of pollutants that companies can release.
If a company goes over--- they pay fines.
If a company is under they can sell there extra allowances to other businesses.

66. Reducing Air Pollution from Vehicles
The EPA requires car makers to meet certain criteria for exhaust.
Use of cleaner fuels and more efficient engines
Hybrids, carpools, public transportation, or biking and walking all reduce air pollution.