Air Chapter 12 Environmental Science What Causes Air

Air Chapter 12 Environmental Science

What Causes Air Pollution? n Clean Air q q q n Nitrogen gas Oxygen gas Small amounts of other gases and water vapor Unclean Air q Primary pollutants n q Put directly into air by humans Secondary pollutants n n Primary pollutant mixed with another pollutant Example – ozone (oxygen mixed with UV light)

Sources of Pollutants n Air Quality Activity

Motor Vehicle Emissions n Gasoline burned by vehicles q Clean Air Act of 1970 n n n Required gradual elimination of lead in gasoline Requires cleaning of exhaust gases before exits vehicle Zero-Emission Vehicle Program in CA q q q No emissions from gasoline No emission-control systems that fail over time Each year more vehicles are required to have zero emissions (ex. Electric vehicles)

Industrial Air Pollution q Scrubbers n Removes harmful substances that would pollute the air q q Electrostatic precipitators n n q Example - Ammonia Used in cement factories and power plants that burn coal Removes dust particles from smoke stacks Smog n n n Air pollution that hangs over urban areas Reduces visibility Pollutants enter the air and chemical reactions occur causing the pollution

Industrial Pollution, etc. n Temperature Inversions q When the air above is warmer than the air below n q Can trap pollution in the atmosphere n q Under normal circumstances, the higher in the atmosphere you go, the colder the air Normally, air currents keep the air pollution from reaching dangerous levels. Causes of temperature inversions n n Mountains Cities are located in valleys

Assignment n n n Section 1 Review Page 308 #1 -4

Air, Noise and Light Pollution n Effects of Air Pollution q Short-term effects n n n q Headache Nausea Irritated eyes, nose, throat Coughing Bronchitis and pneumonia Long-term effects n n n Emphysema Lung cancer Heart disease

Indoor Air Pollution n Sources of indoor pollution q q n Sick-Building Syndrome q q n Plastics Industrial chemicals Buildings with poor air quality Common in hot places where buildings are tightly sealed to keep out heat Ways to reduce indoor air pollution q q Ventilation - mixing outdoor air with indoor air Properly identifying and removing pollutants

Indoor Air Pollution, cont. n Radon Gas q q q Colorless, Odorless, Tasteless Enters home through cracks, holes in foundations When inhaled, radon damages the lungs n n Can cause lung cancer Asbestos q q q Long thin fibers of minerals that are strong and heat resistant and used in insulation Use banned in the 1970 s When inhaled, causes damage to the lungs

Noise Pollution n Noise q n Noise pollutants q n A sound of any kind Airplanes, city traffic, home appliances Health problems caused by noise pollution q q Loss of hearing High blood pressure Stress Loss of sleep (leads to lower productivity)

Noise Pollution, cont. n Decibels q Measurement of intensity of sound n n q Quietest sound you can hear – 0 decibels Sound that causes pain – 120 decibels Permanent deafness occurs after continuous exposure to 120 decibels and higher

Light Pollution n n Does not directly affect human health Does affect our environment q Inefficient lighting n n When lighting is used at night and lost in space because it was directed upward Example q n Billboards and signs that are lit from below Solutions q q q Light from above (downward) Use time controls (only use light when needed) Use low-pressure sodium sources (most efficient)

Assignment n n n Section 2 Review Page 313 # 1 -4, 6

Acid Precipitation n n Rain, sleet or snow that contains high levels of acid What causes acid rain? q q q Fossil fuels are burned Sulfur and nitrogen dioxides enter the atmosphere Forms into acid in the atmosphere Falls to the surface with precipitation Causes living organisms to die or lowers populations of plants and animals

p. H n n n How acidic or basic a substance is Pure water has a p. H of 7. 0 (neutral) Normal precipitation is slightly acidic Acid rain - p. H of 5. 0 or lower Acid rain will drop the p. H of the soil q Acidification n n Causes some nutrients to dissolve and wash away Causes toxic elements to be absorbed by roots

Acid Precipitation & Aquatic Ecosystems n n If the p. H drops, animals may die Acid shock occurs q q q When a sudden influx of acidic water causes a rapid p. H change Affects reproduction and causes birth defects in fish Lime is added to the lake to reverse acid shock

Quick Lab n n Neutralizing Acid Precipitation Page 316

Acid Precipitation and Humans n n n Increase in respiratory problems Trees are damaged Fishermen less able to fish Dissolves calcium carbonate in concrete, limestone buildings and historic monuments International Problem q Pollutants can be released in one geographic area and falls in another hundreds of miles away In 1991, Canada-US Air Quality Agreement q Agreed to reduce acidic emissions that flow across the border

Assignment n n n Section 3 Review Page 317 # 1 -5

Chapter 12 Review Questions n n Pages 319 -321 #6 -19, 21 -26, 28, 33 -34