1. APES Get out lab – keep at table

2. SMOG Ch. 18

3. Smog Localized air pollution in urban areas, mixture of pollutants that form with interaction with sunlight TYPES: 1.Brown 2.Gray

4. Air Pollution & Primary Pollutants Primary Pollutants Undergo Reactions to form Secondary Pollutants C + O 2 CO 2 2C + O 2 2CO + Soot S + O 2 SO 2 N 2 + O 2 2NO

5. Photochemical (Brown) Smog Brown haze Light initiates complex chemical reactions

7. Photochemical Smog in Santiago, Chile

8. Photochemical Smog Reaction VOCs + NO x + Heat + Sunlight yields –Ground level O 3 and other photochemical oxidants –Aldehydes –Other secondary pollutants

9. Fig. 18-11, p. 475 PANS and other pollutants Volatile organic compounds (VOCs) Ozone (O 3 ) Oxygen (O 2 ) Nitric oxide (NO) + Oxygen atom (O) Water vapor (H 2 O) Hydrocarbons UV radiation Peroxyacyl nitrates (PANs) Nitrogen dioxide (NO 2 ) Oxygen (O 2 ) Nitric oxide (NO) Oxygen (O 2 ) Burning fossil fuels Nitrogen (N) in fossil fuel Simplified Model

10. HOW? (Nitric Acid AKA Acid Rain) NO 2 +UV NO + O 2NO + O 2 2NO 2 3NO 2 + H 2 O 2HNO 3 + NO N 2 & O 2 in air react @ high temps nitrogen monoxide Stinky, yellowish brown gas, haze above cities (Nitrogen dioxide) Forms nitric acid & Nitrogen monoxide Nitric Acid = Acid Precipitation

11. HOW? Tropospheric Ozone (BAD!) NO 2 +UV NO + O O + O 2 O 3 Produces free oxygen Tropospheric ozone 

12. HOW? Peroxyacyl Nitrates (PANS) O 2 + hydrocarbons + NO PANS (peroxyacyl nitrates) Burning Eyes Damage Vegetation

13. Photochemical Smog Reaction Fig. 17-6 p. 424

14. Photochemical Oxidants NO 2, O 3, PANS Able to react with & oxidize compounds in atm. or our lungs Respiratory health issues Damaging to vegetation

15. Industrial (Gray) Smog Smoke pollution Sulfur oxides Particulates from burning coal/oil, Problems in China/India/Russia due to lack of pollution controls on smokestacks

16. Industrial Smog Reaction When burned, most carbon in coal and oil converted to CO & CO 2 Soot = unburned coal (suspended particulates) Sulfur dioxide & sulfuric acid created

17. Fig. 18-9, p. 474 Ammonium sulfate [(NH 4 ) 2 SO 4 ] Ammonia (NH 3 ) Sulfuric acid (H 2 SO 4 ) Water vapor (H 2 O) Carbon monoxide (CO) and carbon dioxide (CO 2 ) Sulfur trioxide (SO 3 ) Oxygen (O 2 ) Sulfur dioxide (SO 2 ) Burning coal and oil Oxygen (O 2 ) Sulfur (S) in coal and oilCarbon (C) in coal and oil

18. How? (Carbon) C + O 2 CO 2 + Soot (gray color) 2C + O 2 2CO + Soot #1 human made GHG Incomplete combustion

19. How? (Sulfur) S + O 2 SO 2 (suffocating gas) 2SO 2 + O 2 2SO 3 SO 3 + H 2 O H 2 SO 4 (sulfuric acid, acid rain) 2NH 3 + H 2 SO 4 (NH 4 ) 2 SO 4 (Ammonium Sulfate – GRAY COLOR)

20. Smog also creates greenhouse gases Methane (CH 4 ) Nitrous Oxide (N 2 O

21. Smog Hotter days = O 3 & other components

22. What’s location got to do with it? Cities with sunny, warm & dry climates Greater number of motor vehicles EX: LA; Salt Lake City, Utah; Syndey, Australia; Sao Paulo, Brazil; Bangkok, Thailand; Mexico City, Mexico and Santiago, Chile

23. What’s Location Got to Do With It? Temperature differences help to disperse air pollutants preventing harmful buildup of air toxins Ground air is warmed, rises, then cools = CONVECTION

24. Temperature Inversions Ground air colder than upper air – trap harmful pollutants near ground Cooler air is denser than warmer air above it Pollutants concentrate in stagnant cool layer NO mixing due to density

25. Types of Temperature Inversions Subsidence - Warmer mass enters high altitude region and floats atop a colder air mass. Prevents vertical mixing.

26. Types of Temperature Inversions Subsidence

27. Types of Temperature Inversions Radiation – Occurs at night as ground air cools faster than air above. Sun rises and warms surface – dispersing pollutants that were trapped during night Inversion layer Mountain range Sea breeze Descending warm air mass Decreasing temperature Increasing altitude

28. Types of Temperature Inversions*

29. Where does this occur? Valleys surrounded by mountains

30. Where does this occur? Near coastlines with sunny climage, and surrounded by mountains EX: Los Angeles, CA

31. Where does this occur? Leeward side of mountains