Presentation on theme: "Human Impact on Air Resources Chapter 26.3. Global Impacts of Air Pollution A.Global Warming - Greenhouse Effect - a natural process in which atmospheric."— Presentation transcript:
Human Impact on Air Resources Chapter 26.3
Global Impacts of Air Pollution A.Global Warming - Greenhouse Effect - a natural process in which atmospheric gases trap thermal energy. - over time, the Earths climate has undergone both warming and cooling trends. - the main greenhouse gas carbon dioxide, however, has been increasing due to the increased use of fossil fuels. - Scientists believe this rise in CO 2 has caused the avg. surface temperature of the Earth to rise 0.5 o C over the past century. Video – Greenhouse Effect (2:15 min)
Question! What is the main greenhouse gas?
B. Photochemical Smog - a yellow-brown haze that forms around heavily populated areas. - created by the reaction of car exhaust and oxygen in the atmosphere. - produces ozone (O 3 ) which is harmful to breathe. Video – Future Car (5:01 min)
Question! What is the main cause of smog?
C. Ozone Depletion - ozone (O 3 ) in the upper atmosphere protects the Earth from harmful UV light from the Sun. - chemicals called CFCs were used in the 1960s s as a refrigerant in air conditioners, refrigerators, and freezers. - Scientists discovered that these chemicals were damaging the ozone layer and they are now banned from use in most of the world. - the ozone hole should eventually be repaired in a few hundred years as the CFCs drift into space. Video – Ozone Hole (5:04 min)
Question! What chemical kills the ozone layer?
D. Acid Precipitation - burning fossil fuels that contain sulfur releases toxic sulfur dioxide and nitric oxide into the air. - these combine with moisture in the air to produce sulfuric and nitric acids. - these acids harm aquatic life, plant life, dissolve nutrients from the soil, and increase weathering of buildings and monuments. - most acid rain in the US is from the burning of coal in electrical power plants.
Question! What kind of acid is found in acid rain?
E. Reducing Air Pollution - Government regulations have been very effective in reducing emission of air pollutants. - These include: - emission standards for coal burning power plants and new cars. - banning the use of CFCs. - encouraging the use of alternative energy sources.