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Global Change. Gabby Gabanic Chapter 18-1. Power Plants. Coal-burning. Smoke released into the atmosphere through smokestacks. Usually around 300 meters. Contains high concentrations of sulfur.
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Global Change. Gabby Gabanic Chapter 18-1
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.”
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.
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.”
Impact of Acid Rain • Forests in certain regions are being damaged. • Harming symbiotic fungi in tree roots.
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 Earth’s surface, scientists expect an increased incidence of diseases caused by exposure to ultraviolet radiation.” • Ex. Skin cancer, cataracts and cancer of the retina.
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.
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.”
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.
Greenhouse Effect • Greenhouse effect- traps heat within the atmosphere like the way a greenhouse traps in heat. • Greenhouse gases- insulating effects of certain gases.