1. 1 Progress Report to MDE June 12, 2009 Dr. Konstantin Vinnikov, Acting State Climatologist for Maryland Prof. Russell Dickerson, Department of Atmospheric and Oceanic Science University of Maryland at College Park, MD Observed Diurnal-Seasonal and Longer Scale Variation of Sulfur Dioxide in Maryland Partly supported by NASA

2. 2 TASK: Study Temporal and Spatial Variability of SULFUR DIOXIDE in Atmospheric Air Using Multi-year Observations at Surface Stations at Maryland and its Vicinity. GOAL: Define Temporal and Scale Requirements for Geostationary Satellite Monitoring of Air Pollutants & Evaluate/Validate CMAQ model. DATA: 1.National Parks 2.MDE-run stations

3. 3

4. 4 YEAR 2002 DATA

5. 5 1 STATIONS MAP

6. 6 Altitude = 1073 m above MSL SHENANDOAH NATIONAL PARK: This station is ~1 km above sea level. No local SO 2 emissions. Very weak diurnal cycle. Noticeable seasonal cycle

7. 7 Altitude = 346 m MSL Altitude = 23 m MSL VINTON, VA BLUE RIDGE PWY: Altitude ~350 m No local emissions Weak diurnal cycle. Noticeable seasonal cycle. ALEXANDRIA, VA G. Wash. Mem. Pwy: Traffic emissions. Well pronounced diurnal and seasonal cycles in SO 2.

8. 8 Altitude = 49 m MSL Altitude = 777 m MSL BELTSVILLE, MD: Suburban environment. Traffic emissions. Well pronounced seasonal and diurnal cycles in SO 2. PINEY RUN, MD: Altitude is 777 m. Strong seasonal cycle. Strong diurnal cycle in SO 2 without known sources of local emissions.

9. 9 =7.2 ppb Altitude = 5 m MSL Long-term changes in seasonal and diurnal cycles of SO 2 =9.8 ppb =7.2 ppb =6.3 ppb =4.4 ppb

10. 10 Conclusions: Seasonal cycle of SO 2 with late winter (reduced loss rates due to H 2 O 2 and OH) maximum always exists in surface data at MD and its vicinity. Diurnal cycle of SO 2 depends on diurnal cycle of local pollutants and on diurnal evolution of boundary layer. High elevated monitoring stations at National Parks do not display noticeable diurnal cycle in SO 2. Unexpected well pronounced diurnal cycle in observation of Piney Run, MD station is a mystery! These estimates will be used for model validation. The work is in progress. Seasonal and diurnal cycles of CO and PM 2.5 and other pollutants are going to be studied next.