1. AIR QUALITY & AIR POLLUTION

2. COMPOSITION OF AIR 78% nitrogen 21% oxygen 1% other gases Argon
Carbon dioxide
Methane
Nitrogen oxide
Ozone
CFCs

3. LAYERS OF THE ATMOSPHERE
TROPOPHERE
STRATOSPHERE
OZONE LAYER
MESOPHERE
THERMOSPHERE

5. TROPOSPHERE STRATOSPHERE
4-11 miles above surface
Temperature decreases as altitude increases
Most gas concentration (due to gravity)
Highest air pressure (decreases with altitude)
Weather occurs in this layer
11-30 miles
Gas concentration is lower than troposphere but similar in composition
Less water vapor
More ozone…
Ozone layer: “global sunscreen”… absorbs ~95% UV rays

6. AIR CONVECTIVE CIRCULATION
Natural way of keeping pollutants from reaching dangerous levels
Sun heats earth...warm air rises...carrying pollutants up
THERMAL INVERSION...warm air can trap cooler air below...traps pollutants

7. AIR CONVECTION CELL CIRCULATION

8. AIR POLLUTION
Chemicals in air that are at high enough concentrations to be harmful to living organisms & ecosystems
Natural: Wind blown dust…debris from volcanic eruptions & forest fires
Human generated: burning of fossil fuels…occur mostly in industrialized & urban areas
PRIMARY pollutants: emitted directly into air (cars, factories, volcanoes)…EX: CO, CO2, NOx, SO2
SECONDARY pollutants: result from interaction of primary pollutants… EX: sulfuric acid, nitric acid, ozone