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PM10 Episode Case Study in Cairo: Air Quality & Meteorology Analysis

Explore an in-depth analysis of a PM10 episode in Cairo, Egypt in October 1999, focusing on air quality conditions, weather situations, and key processes that influenced the episode. Understand the impact of meteorological factors on air quality.

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PM10 Episode Case Study in Cairo: Air Quality & Meteorology Analysis

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  1. Section 11Case Studies of Episodes What is a Case Study? How to Conduct Case Studies Examples

  2. What is a Case Study? • Analysis of the causes of an air quality episode • Case studies provide insight into important processes • Components of a case study • Air quality conditions • Weather situation • Summary of episode • Important air quality processes • Important meteorological processes Section 11 – Case Study of Episodes

  3. How to Conduct Case Studies • Select a few air quality episodes to study • Include ramp-up and cleanout days • Review locations, magnitude, and duration of poor air quality • Review surface and upper-air weather patterns • Create backward trajectories to estimate transport • Estimate upwind air quality to quantify local versus background contributions • Review the temperature soundings to estimate vertical mixing • Summarize the important processes that produced the episode Section 11 – Case Study of Episodes

  4. Examples • Each example includes • Location and background • Air quality conditions • Weather situation (surface, upper-air, stability, winds, etc.) • Summary of episode (air quality and meteorology) • Case study examples • PM10 episode • Ozone episode • PM2.5 episode • CO episode • Long-range transport episode • Multi-pollutant episode • Smoke episode Section 11 – Case Study of Episodes

  5. Case Study of PM10 Episode in Cairo, Egypt • Location and background • Air quality conditions • Weather situation • Summary of episode (air quality and meteorology) Section 11 – Case Study of Episodes

  6. Cairo Location – Cairo, Egypt Section 11 – Case Study of Episodes

  7. Air Quality Conditions Time series plot of PM10 concentrations in Cairo in October 1999. The October 20-25, 1999, episode is outlined (Dye et al., 2000). Section 11 – Case Study of Episodes

  8. H Weather Situation (1 of 6) • Surface and upper-air weather patterns 500-mb heights (dm) (solid) and 850-mb temperatures (oC) (dashed) (left), and sea level pressure (mb) and surface wind flags (right) on October 20, 1999, at 1400 LT Section 11 – Case Study of Episodes

  9. L Light northerly winds Weak trough just passed Weather Situation (2 of 6) • Surface and upper-air weather patterns 500-mb heights (dm) (solid) and 850-mb temperatures (oC) (dashed) (left), and sea level pressure (mb) and surface wind flags (right) on October 23, 1999, (high PM day) at 1400 LT Section 11 – Case Study of Episodes

  10. Weather Situation (3 of 6) Moderate northerly winds Strong trough just passed Surface and upper-air weather patterns 500-mb heights (dm) (solid) and 850-mb temperatures (oC) (dashed) (left), and sea level pressure (mb) and surface wind flags (right) on October 25, 1999, (cleanout day) at 1400 LT Section 11 – Case Study of Episodes

  11. 32 20-Oct 21-Oct 22-Oct 23-Oct 31.5 21 24-Oct 25 20 25-Oct 22 31 24 Latitude (degrees) 23 30.5 Short transport on high PM day 30 29.5 29.5 30 30.5 31 31.5 32 32.5 Longitude (degrees) Weather Situation (4 of 6) • Backward trajectories to estimate transport 12-hr backward trajectories ending in Cairo at 1400 LT each day October 20 to 25, 1999. Section 11 – Case Study of Episodes

  12. Weather Situation (5 of 6) • Upper-air nighttime soundings to estimate vertical mixing 0200 LT temperature soundings taken at Helwan from October 20 to 25, 1999. Section 11 – Case Study of Episodes

  13. Warming Height (m) 21 22 25 24 20 23 Temperature (ºC) Weather Situation (6 of 6) • Upper-air daytime soundings to estimate vertical mixing 1400 LT temperature soundings taken at Helwan from October 20 to 25, 1999. Section 11 – Case Study of Episodes

  14. Summary of Episode • Episode characteristics • Weak upper-level troughs passed over and north of Egypt • The troughs lowered surface pressures to the north, thereby weakening the northerly winds, but winds still remained light-to-moderate from the north • Aloft temperatures warmed, the capping inversion lowered, and vertical mixing was reduced • Despite the moderately strong northerly winds, the reduced vertical mixing allowed for high PM10 concentrations • The episode ended when a strong trough followed by a ridge passed over Egypt, increasing the northerly winds and weakening the inversion Section 11 – Case Study of Episodes

  15. Examples • GTT – Please provide examples of other case studies • For each example include • Location and background • Air quality conditions • Weather situation (surface, upper-air, stability, winds, etc.) • Summary of episode (air quality and meteorology) • Case study examples • Ozone episode • PM2.5 episode • PM10 episode (done) • CO episode • Long-range transport episode • Multi-pollutant episode • Smoke episode Section 11 – Case Study of Episodes

  16. Case Study of Ozone Episode • Location and background • Air quality conditions • Weather situation • Summary of episode (air quality and meteorology) Section 11 – Case Study of Episodes

  17. Case Study of Ozone Episode • Youngstown, Ohio, USA • Summer 2002 Section 11 – Case Study of Episodes

  18. 24-hr Backward Trajectory Surface Pressure (msl) 500-mb Heights L H L H L L H L H H H H H H H Jun07th12:00 pmEST Jun13th12:00 pmEST Jun11th12:00 pmEST Jun12th12:00 pmEST Jun08th12:00 pmEST Jun09th12:00 pmEST Jun10th12:00 pmEST Case Study of Ozone Episode 9-11 June 2002 Episode Youngstown Regional 8-hr O3 Maximum 160 * 140 * 120 * 100 Maximum AQI 80 * * 60 * * 40 20 0 7-Jun 8-Jun 9-Jun 12-Jun 13-Jun 10-Jun 11-Jun Section 11 – Case Study of Episodes

  19. 24-hr Backward Trajectory Surface Pressure (msl) 500-mb Heights L H H H H H Jul08th12:00 pmEST Jul10th12:00 pmEST Jul06th12:00 pmEST Jul07th12:00 pmEST Jul09th12:00 pmEST Case Study of Ozone Episode * Youngstown Regional 8-hr O3 Maximum * * * * Section 11 – Case Study of Episodes

  20. Summary of Ozone Episodes • Episode characteristics • Ridge of high pressure created high pressure system • Recirculation was important for the 9-11 June and July 8, 2002 • Episodes occurred on weekdays, which typically have higher emission patterns • Trajectories are useful for diagnosing air movement • Transport of ozone from upwind regions contributed to the ozone on 11 June 2002 Section 11 – Case Study of Episodes

  21. AUSTRALIA SYDNEY Case Study of Ozone Episode in Sydney, Australia • Ozone episode Section 11 – Case Study of Episodes

  22. Eg: Syndey O3 Event Dec 1998 Section 11 – Case Study of Episodes

  23. AUSTRALIA MELBOURNE Case Study of Smoke Episode in Melbourne, Australia • Smoke episode Section 11 – Case Study of Episodes

  24. Case Study of Smoke Episode in Melbourne, Australia Section 11 – Case Study of Episodes

  25. Case Study of Smoke Episode in Melbourne, Australia • Visible satellite image and modeled smoke Section 11 – Case Study of Episodes

  26. How to Conduct Case Studies • Select a few air quality episodes to study • Include ramp-up and cleanout days • Review locations, magnitude, and duration of poor air quality • Review surface and upper-air weather patterns • Create backward trajectories to estimate transport • Estimate upwind air quality to quantify local versus background contributions • Review the temperature soundings to estimate vertical mixing • Summarize the important processes that produced the episode Section 11 – Case Study of Episodes

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