Stack Plume: Looping Strong turbulence http://www.uwm.edu/~kahl/CoVis/Plume/stable.gif Q: Is it at stable or unstable condition? High or low wind speed? Does it happen during the day or night? Is it good for dispersing pollutants?03/30/13 Aerosol & Particulate Research Lab http://www.med.usf.edu/~npoor/3 3
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5. Stack Plume: Coning Strong wind, no turbulence What is the stability class? Good vertical mixing? On sunny or cloudy days? Good for dispersing pollutants? What is the ground level concentration as a function of distance from the stack?03/30/13 Aerosol & Particulate Research Lab 5
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7. Stack Plume: Fanning http://www.med.usf.edu/~npoor/4 Q: What is the stability class? What is the top view of the plume? What is the ground level concentration as a function of distance from the stack?03/30/13 Aerosol & Particulate Research Lab 7
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9. Stack Plume: Fumigation Q: Why can’t the pollutants be dispersed upward? Does it happen during the day or night? What’s your opinion about requiring power plants to reduce their power output from 3 am to 3 hours after sunrise? What is the ground level concentration as a function of distance from the stack?03/30/13 Aerosol & Particulate Research Lab 9
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11. Stack Plume: Lofting Q: Why can’t the pollutants be dispersed downward? When does it happen? Lofting is a transition stage. To which type of plume? What is the ground level concentration as a function of distance from the stack?03/30/13 Aerosol & Particulate Research Lab 11
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13. Stack Plume: Trapping Q: What is the stability class? What is the ground level concentration as a function of distance from the stack? http://www.uwm.edu/~kahl/CoVis/Plume/03/30/13 Aerosol & Particulate Research Lab 13
14. Effect of Surface Discontinuity (a) (b) Warm land Cold water (c) Warm land Cold water Cold land Warm water Q: What is the ground level concentration as a function of distance from the stack?03/30/13 Aerosol & Particulate Research Lab 14
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16. Effects of Terrain on the Plume Pattern Q: Does the shape of the building matter? Is the wake bigger at stable or unstable condition?03/30/13 Aerosol & Particulate Research Lab 16
17. Impact of Building and Stack Location Backwash Downwash Q: Is stack height an important parameter?03/30/13 Aerosol & Particulate Research Lab 17
18. Impact of Stack Height: Stack Upwind of Building03/30/13 Aerosol & Particulate Research Lab 18
19. Impact of Stack Height: Building Supported Stack03/30/13 Aerosol & Particulate Research Lab 19
20. Impact of Stack Height: Stack Downwind of Building Conclusions?03/30/13 Aerosol & Particulate Research Lab 20
21. Cases of Downwash03/30/13 Aerosol & Particulate Research Lab 21
22. Plume Affected by Natural Terrain Irregularity03/30/13 Aerosol & Particulate Research Lab 22
23. Plume Near Very Large Obstacle Unstable Stable03/30/13 Aerosol & Particulate Research Lab 23
24. Plume in a Valley03/30/13 Aerosol & Particulate Research Lab 24
25. Heat Island Effect Q: When does the effect break?03/30/13 Aerosol & Particulate Research Lab 25
26. Plume Affected by Heat Island Effect Toward a city Within a city03/30/13 Aerosol & Particulate Research Lab 26
27. Long-Range Transport • Transport of pollutants hundreds/thousands of miles; resulting in air quality problems far away from the source Examples? Planetary Transport • Stable air above PBL retards vertical mixing • Transport out of PBL to free troposphere takes few hours to few days • Transport to top of troposphere with uniform mixing takes about a week (for long-lived pollutants, e.g. CO2, CH4, CFC) Why only long-lived?03/30/13 Aerosol & Particulate Research Lab 27
28. Summary Take 2 minutes to summarize here what you have learned from this