1. Gabby Gabanic Chapter 18-1

2. Power Plants Coal-burning. Smoke released into the atmosphere through smokestacks. Usually around 300 meters. Contains high concentrations of sulfur. Purpose: To release sulfur-rich smoke high into the atmosphere, where winds would disperse and dilute it.

3. Power Plants (continued) Were first introduced in the mid- 1950s. Common in the United States and Europe. The sulfur released from the smokestacks can combine with water vapor to produce sulfuric acid. Snow/Rain bring the sulfuric acid back down to Earth.

4. Acid Rain Acidified precipitation. Northeastern United States and Southeastern Canada is where it is most severe. They are areas that are downwind from coal-burning plants in the Midwest.

5. Acid Rain Process

6. Impact of Acid Rain Forests in certain regions are being damaged. Harming symbiotic fungi in tree roots.

7. The Ozone Hole Scientists said it was as if an ozone eater were causing a mysterious zone of below-normal concentration. Because the decrease in ozone allows more ultraviolet radiation to reach the Earths surface, scientists expect an increased incidence of diseases caused by exposure to ultraviolet radiation. Ex. Skin cancer, cataracts and cancer of the retina.

8. Ozone Hole

9. Destruction of the ozone Chlorofluorocarbons (CFC)- class of chemicals. Considered extremely stable, harmless, and a nearly ideal heat exchanger. Used as coolants. Refrigerators and air conditioners. Aerosol propellants-spray cans. Foaming agents-production of plastic-foam cups and containers. Primary cause of the ozone hole.

10. Destructions of ozone (cont.) Ultraviolet radiation from the sun is able to break the usually stable bonds in CFCs. The resulting free chlorine atoms then enter into a series of reactions that destroy the ozone.

11. Global Temperatures Temperature of the Earth has been increasing steadily since the 1950s. Global warming happens in periods. Sunspot cycles may contribute to this along with human activity.

12. Greenhouse Effect Greenhouse effect- traps heat within the atmosphere like the way a greenhouse traps in heat. Greenhouse gases- insulating effects of certain gases.