Atmospheric Science and Air Pollution.ppt

This lecture will help you understand:
The Earth’s atmosphere
Outdoor pollution and solutions
Stratospheric ozone depletion
Acidic deposition and consequences
Indoor air pollution and solutions
The atmosphere
Atmosphere = the thin layer of gases that surrounds Earth
Absorbs radiation and moderates climate
Transports and recycles water and nutrients
78% nitrogen gas, 21% oxygen gas, 1% other gases
Its four layers differ in temperature, density position
Minute concentrations of permanent (remain at stable concentrations) and variable gases (varying concentrations)
Human activity is changing the amounts of some gases
The atmosphere’position
The first two layers of the atmosphere
Troposphere = bottommost layer
Air for breathing, weather
Temperature declines with altitude
Tropopause = limits mixing between troposphere and the layer above it
Stratosphere = 11-50 km (7-31 mi) above sea level
Drier and less dense, with little vertical mixing
Colder in its lower regions
Contains UV radiation-blocking ozone, 17-30 km (10-19 mi) above sea level
The two highest levels of the atmosphere
Mesosphere = 50-80 km (31-56 mi) above sea level
Extremely low air pressure
Temperatures decrease with altitude
Thermosphere = atmosphere’s top layer
Extends upward to 500 m (300 mi)
The atmosphere’s four layers
Atmospheric properties
Atmospheric pressure = measures the force per unit area produced by a column of air
Decreases with altitude
Relative humidity = the ratio of water vapor a given volume of air contains to the amount it could contain at a given temperature
Temperature = varies with location and time
Solar energy heats the atmosphere
The spatial relationship between the Earth and sun determines the amount of solar energy striking the Earth
Energy from the sun
Heats air
Moves air
Creates seasons
Influences weather and climate
Solar radiation is highest near the equator
Solar energy creates seasons
Because the Earth is tilted
Each hemisphere tilts toward the sun for