AREP GURME Section 11 Case Studies of Episodes What is a Case Study? How to Conduct Case Studies Examples

AREP GURME 2 Section 11 – Case Study of Episodes 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

AREP GURME 3 Section 11 – Case Study of Episodes 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

AREP GURME 4 Section 11 – Case Study of Episodes 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 PM 10 episode Ozone episode PM 2.5 episode CO episode Long-range transport episode Multi-pollutant episode Smoke episode

AREP GURME 5 Section 11 – Case Study of Episodes Case Study of PM 10 Episode in Cairo, Egypt Location and background Air quality conditions Weather situation Summary of episode (air quality and meteorology)

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

AREP GURME 7 Section 11 – Case Study of Episodes Air Quality Conditions Time series plot of PM 10 concentrations in Cairo in October The October 20-25, 1999, episode is outlined (Dye et al., 2000).

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

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

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

AREP GURME 11 Section 11 – Case Study of Episodes 12-hr backward trajectories ending in Cairo at 1400 LT each day October 20 to 25, Backward trajectories to estimate transport Weather Situation (4 of 6) Longitude (degrees) Latitude (degrees) 20-Oct 21-Oct 22-Oct 23-Oct 24-Oct 25-Oct Short transport on high PM day

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

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

AREP GURME 14 Section 11 – Case Study of Episodes 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 PM 10 concentrations The episode ended when a strong trough followed by a ridge passed over Egypt, increasing the northerly winds and weakening the inversion Summary of Episode

AREP GURME 15 Section 11 – Case Study of Episodes 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 –PM 2.5 episode –PM 10 episode (done) –CO episode –Long-range transport episode –Multi-pollutant episode –Smoke episode

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

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

AREP GURME 18 Section 11 – Case Study of Episodes 500-mb Heights Surface Pressure (msl) 24-hr Backward Trajectory Jun 07 th 12:00 pm EST H Jun 08 th 12:00 pm EST H H Jun 09 th 12:00 pm EST H H L Jun 10 th 12:00 pm EST H H H Jun 11 th 12:00 pm EST H H L Jun 12 th 12:00 pm EST L L Case Study of Ozone Episode 9-11 June 2002 Episode Jun8-Jun9-Jun 10-Jun11-Jun12-Jun13-Jun Maximum AQI * * * * * * Youngstown Regional 8-hr O3 Maximum * Jun 13 th 12:00 pm EST L

AREP GURME 19 Section 11 – Case Study of Episodes Jul 06 th 12:00 pm EST H Case Study of Ozone Episode 500-mb Heights Surface Pressure (msl) 24-hr Backward Trajectory * * * Jul 07 th 12:00 pm EST H * * Youngstown Regional 8-hr O3 Maximum H H Jul 08 th 12:00 pm EST L Jul 09 th 12:00 pm EST H Jul 10 th 12:00 pm EST

AREP GURME 20 Section 11 – Case Study of 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 Summary of Ozone Episodes

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

AREP GURME 22 Section 11 – Case Study of Episodes Eg: Syndey O 3 Event Dec 1998

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

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

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

AREP GURME 26 Section 11 – Case Study of Episodes 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