DRY DEPOSITION OF SULFUR CONTAINING SPECIES TO THE WATER SURFACE SAMPLER AT TWO SITES

摘要

Sulfate dry deposition increases the deteriorating effects on environment. Sulfate can be deposited from atmosphere to water via both particulate (SO_4~(2-): sulfate) and a gas (SO_2: sulfur dioxide) form. In this research, the fluxes of gaseous (SO_2) and particulate (SO_4~(2-)) species were measured employing a water surface sampler (WSS) and glass fiber filters (GFFs) on the knife-edge surrogate surface (KSSs) in the campus of Uludag University and the city of Bursa, Turkey. Sampling program was conducted intermittently between September 2004 and March 2005. Average total sulfate fluxes measured with the WSS at the Uludag University campus and in the city of Bursa were 58 ± 41 and 235 ± 43 mg m~(-2) d~(-1), respectively. The total sulfate fluxes measured at Bursa were higher and this was probably due to greater sulfur containing species in its atmosphere. The dry deposition of gaseous SO_2 flux was calculated by subtracting the particulate flux collected with the KSSs from the total flux (particulate sulfate plus SO_2 flux) obtained by the WSS. An automatic SO_2 analyzer was used concurrently to measure the ambient concentration of gaseous SO_2. The average SO_2 gas fluxes and ambient SO_2 concentrations were 18 ± 28 and 54 ± 48 mg m~(-2) day~(-1) and 11 ± 7 and 49 ± 14 μg m~(-3) for the campus and the city, respectively. The measured gaseous SO_2 fluxes and ambient concentrations were used to calculate the mass transfer coefficient. The calculated MTC values for the campus and the city were 0.8 ± 1.0 and 1.2 ± 1.1 cm s~(-1), respectively. These values were in agreement with previously reported dry deposition velocities for SO_2.