Aim: What are the major outdoor air pollutants?

Major Outdoor Air Pollutants: Carbon Oxides CO: Carbon Monoxide Forms during combustion of carbon containing materials. Problems: heart attacks, asthma, emphysema. Nausea, dizziness, confusion, death! CO2: Carbon Dioxide 93% forms naturally in C cycle. Rest from humans. Problems: heat exhaustion, loss of food production Cars, factories, smokestacks, burning forests Burning fossil fuels

Major Outdoor Air Pollutants: Nitrogen Oxides (NO) Nitric oxide Forms under high temps w/combustion (HNO3) Nitric acid Forms when NO2 reacts w/water vapor Problems: irritate eyes. Nose, throat, lung conditons, lower visibility, stunt plant growth. Car engines, coal power plants, lightening Photochemical smog: citities

Major Outdoor Air Pollutants: Sulfur Oxides (SO2 ): Sulfur Dioxide Forms naturally: 1/3 sulfur cycle. 2/3 from human combustion. Problems: In atm. Converts to aerosols. (H2SO4): Sulfuric Acid In aresols Problems: reduce visibility, breathing problems, damage crops, water supplies, corrode metal, damage buildings. Coal and industrial plants, smelting, ASIAN BROWN CLOUD

Major Outdoor Air Pollutants **Particulates** Suspended particulate matter (SPM) by EPA Fine Ultrafine Sources: 62% natural from dust, wildfires, sea salt. 38% from humans: cars, coal plants, factories, construction. Human health and environmental impact

Major Outdoor Air Pollutants (O3): Ozone Problems: respiratory issues, lung and heart disease. Damages plants, rubber, fabrics, and paints. (VOCs): Volatile organic compounds Forms: naturally or exits in atmosphere. Comes from plants CH4: Methane more harmful then CO2 at warming. Photochemical smog Plants, wetlands, humans, cows, landfills, oil and natural gas wells.

METHANE

Chemical Reactions That Form Major Outdoor Air Pollutants Table 18-1 Table 18-1, p. 470

Statue Corroded by Acid Deposition and Other Forms of Air Pollution, RI, U.S. Figure 18.7: Acid deposition and other forms of air pollution have corroded this statue in Newport, Rhode Island (USA). Fig. 18-7, p. 471

Case Study: Lead Is a Highly Toxic Pollutant (1) In air, water, soil, plants, animals Does not break down in the environment Human health and environmental impact Children most vulnerable Can cause death, mental retardation, paralysis

Case Study: Lead Is a Highly Toxic Pollutant (2) Reduction of lead (Pb) Unleaded gasoline Unleaded paint Still problems 15-18 million children have brain damage Need global ban on lead in gasoline and paint

Solutions: Lead Poisoning, Prevention and Control Figure 18.8: Individuals matter. There are several ways to help protect children from lead poisoning. Questions: Which two of these solutions do you think are the most important? Why? Fig. 18-8, p. 472

Science Focus: Detecting Air Pollutants Chemical instruments Satellites Lasers and remote sensors Biological indicators Lichens

Natural Capital: Lichen Species, Vulnerability to Air Pollutants Figure 18.A: Natural capital. Old man’s beard (Usnea trichodea) lichen (left) is growing on a branch of a larch tree in Gifford Pinchot National Park in the state of Washington (USA), and red and yellow crustose lichens (right) are growing on slate rock in the foothills of the Sierra Nevada near Merced, California (USA). Scientists can use such lichens to detect the presence of specific air pollutants and to track down their sources. Fig. 18-A, p. 473

Burning Coal Produces Industrial Smog Chemical composition of industrial smog Reduction of this smog in urban cities of the United States China and smog Human deaths Need strong standards, especially for coal burning

How Pollutants Are Formed from Burning Coal and Oil, Leading to Industrial Smog Figure 18.9: This is a greatly simplified model of how pollutants are formed when coal and oil are burned. The result is industrial smog. Fig. 18-9, p. 474

Carbon monoxide (CO) and carbon dioxide (CO2) Ammonium sulfate [(NH 4 )2SO4] Ammonia (NH3) Sulfuric acid (H2SO4) Carbon monoxide (CO) and carbon dioxide (CO2) Water vapor (H2O) Sulfur trioxide (SO3) Oxygen (O2) Sulfur dioxide (SO2) Burning coal and oil Figure 18.9: This is a greatly simplified model of how pollutants are formed when coal and oil are burned. The result is industrial smog. Oxygen (O2) Sulfur (S) in coal and oil Carbon (C) in coal and oil Fig. 18-9, p. 474

Industrial Smog in India Figure 18.10: Industrial smog hangs over a factory in an Indian city. Fig. 18-10, p. 474

Sunlight Plus Cars Equals Photochemical Smog Chemical composition Sources VOCs + NOx + Heat + Sunlight yields Ground level O3 and other photochemical oxidants Aldehydes Other secondary pollutants Human health and environmental impact

A Model of How Pollutants That Make Up Photochemicals Are Formed Figure 18.11: This is a greatly simplified model of how the pollutants that make up photochemical smog are formed. Fig. 18-11, p. 475

Global Outlook: Photochemical Smog in Santiago, Chile Figure 18.12: Global Outlook: Photochemical smog is a serious problem in Santiago, Chile. Question: How serious is photochemical smog where you live? Fig. 18-12, p. 475

Several Factors Can Decrease or Increase Outdoor Air Pollution (1) Outdoor air pollution may be decreased by Settling of particles due to gravity Rain and snow Salty sea spray from the ocean Winds Chemical reactions

Several Factors Can Decrease or Increase Outdoor Air Pollution (2) Outdoor air pollution may be increased by Urban buildings Hills and mountains High temperatures Emissions of VOCs from certain trees and plants Grasshopper effect Temperature inversions Warm air above cool air prevents mixing

A Temperature Inversion Figure 18.13: Frequent thermal inversions and the presence of many cars and industries lead to photochemical smog in downtown Los Angeles, California (USA). Fig. 18-13, p. 476

Summary: Should construction of tall smokestacks be banned in an effort to promote greater emphasis on preventing air pollution and acid deposition? Explain.

Homework: Read Chapter 18 Pages 481-484