1. Air

2. Air Pollution
a substance that is present in the air in an amount that is undesirable or harmful to living things.
Air pollution can be in the form of
solid, liquid, or gases.

3. Most air pollution is the result of human activity but pollutants also come from natural sources.
Examples: volcanoes, salt from ocean, pollen/spores from plants.

4. Primary Pollutant
pollutant that is put directly into the air by human activity
Example: soot from smoke stacks

5. Secondary Pollutant
formed when a primary pollutant comes into contact with other primary pollutants, or when naturally occurring substances, like water vapor, combine and a chemical reaction takes place.
Examples : ozone + nitrogen dioxide = NO2

6. Types of Air Pollution

7. 1. Vehicles-
The majority of air pollution comes from gasoline burned in motor vehicles.

8. Clean Air Act (1970)
gives EPA the authority to regulate automobile emissions.
catalytic converters clean exhaust before they exit a tailpipe
one effective way to reduce air pollution is to carpool.
use alternative forms of energy

9. 2. Industrial Air Pollution
Most burn fossil fuels to get the energy they need. Causes huge quantities of oxides to be released.
Some industries produce volatile organic compounds (VOC’s), which form toxic fumes.

10. Controlling Air Pollution from Industries
Clean Air Act requires scrubbers or other pollution-control devices.
removes some noxious substances, moves gases through a spray of water that dissolves pollutants. Removes particulates.

11. 3. Smog Main Causes: pollutants released by cars and industries.
combination of smoke and fog.
Air pollution that hangs over urban areas and reduces visibility.
- results from chemical reactions involving sunlight, nitrogen oxides, and hydrocarbons.
Main Causes: pollutants released by cars and industries.

12. Effects on Human Health
Chronic Bronchitis
Asthma
Emphysema
Lung Cancer

13. Acid Precipitation
Highly acidic (pH < 5 ) precipitation that results from the burning of fossil fuels.
releases oxides of sulfur and nitrogen as byproducts.
Oxides combine with water in the atmosphere forming sulfuric acid and nitric acid, which falls as precipitation
can dissolve calcium carbonate in concrete and limestone (eats away historic monuments)