Ambient concentration, dry deposition flux and overall deposition velocities of particulate sulfate measured at two sites

Abstract

In this study, the particulate sulfate fluxes were measured employing the knife-edge surrogate surfaces (KSSs). The sampling program was conducted intermittently between September 2004 and March 2005 in the Uludag University campus and the city of Bursa, Turkey. Ambient air samples (n = 20) and deposition fluxes (n = 20) were sampled simultaneously at these two sites. Average particulate sulfate dry deposition fluxes for the campus and city were 30.9 +/- 34.2 (average +/- 1 S.D.) and 154.9 +/- 79.5 mg m(-2) day(-1), respectively. The measured fluxes were in general higher than those measured in other places. Concurrently, measured ambient air concentrations were 15.2 +/- 6.7 mu g m(-3) and 32.5 +/- 28.3 mu g m(-3) for the campus and the city, respectively. The city had higher ambient air sulfate concentrations and this was mainly due to its proximity to the sources of sulfur emissions and micrometeorological factors. The average overall sulfate dry deposition velocities, calculated by dividing the fluxes to the corresponding concentrations were 3.0 +/- 3.9 cm s(-1) for the campus and 7.5 +/- 4.0 cm s(-1) for the city.