CHARACTERISTICS OF THE ATMOSPHERE

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

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

 Atmospheric Temperature  As altitude increases, temperature decreases  Lower part of atmosphere is warmer  Contains high percentage of gases that absorb solar energy

Layers of the Atmosphere  Troposphere  Stratosphere  Mesosphere  The layer in which we live  Lies next to Earth’s surface  Home of the Ozone layer  Middle layer  Coldest layer

Layers of the Atmosphere cont’d  Thermosphere  Ionosphere  Edge of the Atmosphere  Uppermost layer  Home of the Auroras  Upper Mesosphere and Lower Thermosphere  Nitrogen and Oxygen absorb harmful solar energy

GLOBAL WINDS AND LOCAL WINDS

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

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

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

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

 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

Local Winds  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

 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

AIR POLLUTION

 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)

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

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

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

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