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Progress Report to MDEJune 7, 2010

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 2008-2010Diurnal-Seasonal Variation of

PM2.5 in Maryland

Our goal is to depict the seasonal and daily cycles in SO2 and PM2.5 and to reveal and evaluate effects of changes in Maryland Power Plants SO2 emissions on PM2.5.

2008-10 OBSERVED VARIATIONS OF PM2.5 AT MD STATIONS

DIURNAL-SEASONAL PATTERN

2008-10 OBSERVED VARIATIONS OF SO2 AT MD STATIONS

DIURNAL-SEASONAL PATTERN

DIURNAL-SEASONAL PATTERNMD Power Plants SO2 Emissions

PM2.5 vs. SO2

OBSERVED PM2.5 OBSERVED SO2

MD POWER PLANTS SO2 EMISSIONS

PM2.5

SO2

OBSERVATIONS 2008-10

Diurnal/Seasonal Variation and Variability of PM2.5 Maryland, Surface Stations Hourly Observations 2008-2010

Take home messages:

1. The residual layer and PBL dynamics play a major role in the daily cycle of surface concentrations of SO2 and PM2.5.

2. Concentrations of SO2 peak in mid day because the major sources are aloft and vertical mixing is faster in daylight hours.

3. PM2.5 shows a major summer maximum and a minor winter maximum.

4. The winter maximum occurs at night because much of the PM is primary.

5. The summer max is broad-based because much of the PM is secondary and is transported aloft.