CHAPTER 4 LAND WATER AND AIR SOURCES Section 4: Air Pollution and Solutions

How Does the Scent Spread? (Discover Activity pg. 138) 1.Choose a placed to stand so that you and your classmates are evenly distributed around the room. 2.Your teacher will spray some perfume in one corner of the room. 3.Raise your hand when you first smell the perfume. Think it over: Describe the pattern you observed as people raised their hands. How do you think the scent traveled across the room?

I. - Air = a mixture of nitrogen, oxygen, carbon dioxide, water vapor, and other gases A. gases cycle between the atmosphere and living things. a. Ensures that air will not run out b. Can not ensure that air will be clean B. Emissions- pollutants that are released into the air. 1. factories, motor vehicles C. Natural causing pollutants as well: erupting volcano (smoke)

II. Smog- A. Photochemical Smog – a thick brownish haze formed when certain gases in the air react with sunlight 1. when the smog levels are high, it settles as a haze over a city B. Sources of Smog The major sources of smog are the gases emitted by automobiles and trucks. 1. ozone- the major chemical found in smog. a. Made up of hydrocarbons and nitrogen oxides b. Causes lung infections c. damages body’s defenses against infection

C. Temperature Inversion- a layer of warm air prevents the rising air from escaping. 1. polluted air is trapped close to the Earth’s surface. 2. smog is more dangerous at this time III. Acid Rain- precipitation that is more acidic than normal bc of air pollution Acid rain is caused by the emissions from power plants and factories that burn coal and oil.

A. Coal and oil produce: nitrogen and sulfur oxides when they are burned. 1. gases react with water vapor in the air = sulfuric acid =acid rain 2. Negative effects: a. Changes pH of water sources (affects organisms=fish) b. Damages leaves and stems of plants c. Changes nutrient levels in the soil for future plants d. Damages stone and metal = looks like it is melting e. Automobiles rust more quickly

IV.Indoor Air Pollution- Some substances that cause indoor air pollution, such as dust and pet hair, bother only those people who are sensitive to them. Other indoor air pollutants, such as toxic chemicals can affect anyone. Ex: glues and cleaning supplies give off toxic fumes A. Carbon Monoxide- a colorless, odorless gas 1. formed when wood, coal, oil, or gas are incompletely burned. 2. is deadly when it builds up in a house 3. install a CO detector for protection

B. Radon- a colorless, odorless gas that is radioactive 1. formed naturally by certain rocks underground 2. enters homes through cracks in basement walls 3. causes lung cancer and other health problems 4. unsure of a safe level of radon = install ventilation system in homes

V. Reducing Air Pollution- The key to reducing air pollution is to control emissions. Ex: Clean Air act - regulates the amt of certain pollutants released into the air. A. Controlling Emissions From Factories- 1. tall smoke stacks with devices placed inside to treat emissions: scrubbers a. Produce white smoke = steam instead of dirty smoke

2. Controlling Emissions From Vehicles- a. Car and trucks have pollution-control devices Ex: catalytic converter = reduces CO, hydrocarbons, and nitrogen oxides b. Vehicles required to pass an emissions test 3.What You Can Do- a. Reduce certain types of energy use: 1. burning fuels for electricity and transportation Ex: take public transportation, carpool, walk, or ride a bike = fewer emissions