Characterization of PM_(2.5) in the Baltimore Washington Corridor

摘要

1. Most PM_(2.5) at Ft. Meade this past year consisted of ammonium sulfate and carbonaceous material. 2. Ft. Meade PM_(2.5) annual and seasonal values appear to be consistent with other sites in the Mid-Atlantic Region. 3. Summer and winter experience the highest PM_(2.5) concentrations and greatest inter-seasonal contrasts in composition. 4. In both summer and winter 40% of the PM_(2.5) is carbonaceous and 60% is inorganic (with summer having the highest concentrations). 5. The inorganic material is primarily ammonium sulfate in summer and an equal mix of ammonium sulfate and nitrate in the winter. 6. The carbonaceous material is about 80% organic and 20% soot in all seasons. 7. Summer episodes of low to high to low PM_(2.5) concentrations seem to occur in 5-day periods, with near maximum concentrations on one to three day. Winter episodes seems to be of much shorter duration (2-3 days).