1. DIURNAL AND SEASONAL VARIATIONS OF SO 2 and OTHER ATMOSPHERIC POLLUTANTS OBSERVED AT PINEY RUN STATION AND ITS VICINITY Konstantin Vinnikov and Russell Dickerson – University of Maryland at College Park Nickolay Krotkov – GSFC/NASA Edwin Gluth and Najma Khokhar – Maryland Department of Environment Frostburg, MD Campaign Data Meeting. GSFC, January 27, 2011

2. There are two surface stations with multi-year hourly CO observation in MD. The Beltsville’s record before October 2007 does not look homogeneous and is excluded from analysis. 1.CO Diurnal cycle in both sites is almost negligible. 2.CO Seasonal cycle in both sites is very week but well pronounced with summer time minimum. 3.The estimates of scales of CO temporal autocorrelation exceed 8 hours at Frostburg Reservoir station for all seasons and at Beltsville, MD station – for cold season. Warm season scale estimates at Beltsville, MD are mostly smaller and are about 6 hours. 4.These scales estimates does not have noticeable diurnal cycle.

3. 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.

4. 4 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

5. It is assumed that lag-correlation functions of observed temporal SO 2 variations can be approximated as R(t) =exp(-τ/T), where τ is lag, and T is decay time. This time is needed for observed anomaly of SO 2 concentration to decrease e times. For two physical processes with decay times T 1 and T 2, the resulted decay time 1/T=1/T 1 +1/T 2 or T=T 1 T 2 / (T 1 +T 2 ). The resulted T is always smaller than the smallest of T 1 and T 2. SO 2 LOCAL RESIDENCE TIME IN HOURS Piney Run estimates: T 1 ≈10h is Meteorological Processes Time Scale for CO. T≈5h is SO 2 Local Residence Time Scale. T 2 ≈10h is estimate of SO 2 Chemical Life Time Scale

6. CURRENTLY AVAILABLE 2010 DATA OF OBSERVATION AT PINEY RUN STATION. All these data will be quality controlled and corrected, if necessary. The relevant emissions data are not yet available for the 4 th Quarter of 2010.

7. PINEY RUN, MD AIR QUALITY STATION. ELEVATION ≈ 777m ABOVE MSL. 2010: DIURNAL-SEASONAL VARIATIONS IN THE OBSERVED CONCENTRATIONS OF ATMOSPHERIC POLLUTANTS

8. Preliminary conclusions: Observations reveal well pronounced diurnal and seasonal variations of main atmospheric pollutants at Piney Run station. Full 2010 observation data are not yet available. They will be quality controlled and released a few months later. Statistically evaluated scale of residence time of SO2 fluctuations at Piney Run is about 5 hours. Statistically evaluated scale of residence time of CO fluctuations at Piney Run is about 10 hours. Estimated scale of chemical life time of SO2 at Piney Run is about 10 hours.