Air

1. Air What causes air pollution? Chapter 12 Section 1

2. Air Pollution • Harmful substances build up in the air to unhealthy levels • Primary – put directly into the air by human activity • Secondary – primary pollutant comes into contact with other primary pollutants or other substances such as water vapor and a chemical reaction takes place

3. Primary Pollutants in the U. S. • Carbon monoxide – cars, trucks, buses, small engines • Nitrogen oxide – burning fuels in vehicles, power plants, industrial boilers • Sulfur dioxide – burning fossil fuels • Volatile organic compounds – burning fuels, especially vehicles • Particulate matter – construction, agriculture, forestry & fires, vehicles, industry

4. Motor Vehicle Emissions • One-third of air pollution comes from gasoline burned in vehicles • Clean Air Act of 1970 and 1990 allows EPA to regulate emissions • ZEV – zero emission vehicles, no tailpipe, no emissions form gasoline, and no emission control systems that wear-out over time. Est. in 1990 in California, adopted by Maine, Massachusetts, New York and Vermont

5. Industrial Air Pollution • Industry and power plants burn fossil fuels which release nitrogen oxide and sulfur dioxide • Clean Air Act requires scrubbers to clean air from smoke stacks • Smog – combination of auto exhaust and ozone, caused by pollutants from vehicles and industry

6. Smog

7. Temperature Inversions • Air above is warmer than the air below so pollution is trapped in the lower layer