The spatial and temporal variations of inhalation-level airborne particulate matter in four Wards of Washington, DC were characterized during two six-week observation periods in the summer and fall of 2003. The average aerosol mass densities during the summer (19.3 μg m −3) were roughly double the average values observed during the fall (10.0 μg m−3). In general, a concentration gradient is observed from north to south across the District of Columbia with the gradient becoming more pronounced in the summer time. The fine aerosol size fractions centered at 0.15 and 0.30 microns dominated the mass distributions during both observation periods and the smallest size fraction showed a strong (0.79) correlation with wind speed during the summer IOP but negligible correlations with temperature and relative humidity. This may be an indication that non-local sources are contributing significantly to the fine aerosol fraction during this season.
Abegaz, Samuel, "Seasonal spatial and temporal distribution of daytime inhalation-level particulate matter in Washington, DC" (2011). Faculty Bibliography. 1043.