1. Copyright © 2013 Pearson Education, Inc. The Atmosphere: An Introduction to Meteorology, 12 th Lutgens Tarbuck Lectures by: Heather Gallacher, Cleveland State University Chapter 13: Air Pollution Copyright © 2013 Pearson Education, Inc.

2. The Threat of Air Pollution

3. Copyright © 2013 Pearson Education, Inc. The Threat of Air Pollution  Natural air pollution:  Dust storms, ash from volcanoes, pollen and spores, and smoke from wildfires are all forms of natural air pollution.  Human caused air pollution:  Smoke, soot, and other gases from chimneys, smog, and carbon monoxide are among the human causes of air pollution.

4. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Air pollutants are particles and gases in concentrations that endanger the health and well- being of organisms.  Primary pollutants are emitted directly from identifiable sources.  Secondary pollutants are produced via chemical reactions in the atmosphere with primary pollutants.

5. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Primary pollutants:  These pollutants consist of particulate matter, which is a mixture of solid particles and liquid droplets found in the air.  Fine particles are less than 2.5 micrometers in diameter  These are from combustion, wood burning, and power generation.  Coarse particles are less than 10 micrometers.  These particles come from dirt roads and crushing and grinding operations.

6. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution

7. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Sulfur dioxide (SO 2 )  SO 2 is a colorless gas originating from the combustion of sulfur-containing fuel, such as coal and oil.  Important sources are power plants, smelters, pulp and paper mills, and petroleum refineries.  SO 2 is also a cause of acid rain.

8. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Nitrogen oxide (No x )  Nitrogen oxides are gases that form during the high- temperature combustion of fuel when nitrogen in the air or fuel reacts with oxygen.  Motor vehicles and power plants are the primary sources.  It is also a contributor to acid rain.

9. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Volatile organic compounds (VOCs):  VOCs are also called hydrocarbons.  They encompass a wide array of solids, liquids, and gases.  Carbon monoxide (CO):  CO is a colorless, odorless, and poisonous gas produced by the incomplete burning of coal, wood, and oil.  More than three-quarters of U.S. emissions are from motor vehicles and nonroad equipment.  Lead (Pb):  Lead was formerly added to gasoline to prevent engine knock.  Occasional violations still occur at lead smelters.

10. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution

11. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Secondary air pollution:  Air pollution in urban and industrial areas is called smog, a combination of smoke and fog.  Photochemical reactions are triggered by strong sunlight.  Nitrogen oxides absorb sunlight in the presence of VOCs.  It is a noxious mixture of gases and particulates.  The major component is ozone.

12. Copyright © 2013 Pearson Education, Inc. Sources and Types of Air Pollution  Volcanic smog (Vog):Vog  This occurs in active volcanoes.

13. Copyright © 2013 Pearson Education, Inc. Trends in Air Quality

14. Copyright © 2013 Pearson Education, Inc. Trends in Air Quality  Clean Air Act of 1970:  It was responsible for the creation of the Environmental Protection Agency.  This legislation set standards for the four primary pollutants as well as the secondary pollutant.  Primary  Particulates  SO 2  NO x  CO  Secondary  Ozone

15. Copyright © 2013 Pearson Education, Inc. Trends in Air Quality  Short term:  Acute effects refers to levels that might be life threatening within a period of hours or days.  Long term:  Chronic effects occur when levels cause gradual deterioration of fhysiological functions over a span of years.

16. Copyright © 2013 Pearson Education, Inc. Trends in Air Quality  Air Quality Index (AQI):  The AQI is an indicator for reporting daily air quality to the general public.  The EPA calculates the AQI for the five pollutants regulated by the Clean Air Act.  The AQI scale runs from 0–500.  Less than 100 on the scale is good.  Greater than 100 is considered unhealthy.

17. Copyright © 2013 Pearson Education, Inc. Trends in Air Quality www.airnow.gov

18. Copyright © 2013 Pearson Education, Inc. Meteorological Factors Affecting Air Pollution  Wind as a factor

19. Copyright © 2013 Pearson Education, Inc. Meteorological Factors Affecting Air Pollution  The role of atmospheric stability:  This determines how far the pollutants will move vertically.  Mixing depth is the vertical distance between Earth’s surface and the height of convectional movement.  When air is stable, there is little convection and the mixing depths are small.  When air is unstable air, there is greater convection and the mixing depths are large.

20. Copyright © 2013 Pearson Education, Inc. Meteorological Factors Affecting Air Pollution  Surface temp inversions

21. Copyright © 2013 Pearson Education, Inc. Meteorological Factors Affecting Air Pollution  Inversions aloft

22. Copyright © 2013 Pearson Education, Inc. Acid Precipitation  Wet deposition:  Through a series of chemical reactions, pollutants emitted from sources, such as power-generating plants, ore- smelting, petroleum refining and motor vehicles of all kinds, are converted to acids then fall as rain or snow.  Dry deposition  Acid-producing chemicals may become incorporated into dust or smoke and then fall to the ground.

23. Copyright © 2013 Pearson Education, Inc. Acid Precipitation  Extent and potency of acid precipitationacid precipitation

24. Copyright © 2013 Pearson Education, Inc. Acid Precipitation

25. Copyright © 2013 Pearson Education, Inc. Acid Precipitation  Effects of acid precipitation  It lowers the natural pH of lakes and rivers.  It reduces agriculture yields.  It corrodes metals and stone structures.

26. Copyright © 2013 Pearson Education, Inc. End Of Chapter 13