The influence of basic aerosols on throughfall fluxes of sulfate, ammonium and nitrate in three oak stands along a distance gradient from a lime quarry

Three oak stands (Quercus petraea and Quercus robur) in the Weinviertel, Lower Austria, located along a distance gradient from a lime quarry, were studied to determine the effects of basic aerosols on the deposition of ammonium, nitrate and sulfate. Higher concentrations of limestone aerosols in the vicinity of the quarry are suggested by higher Ca2+ fluxes and pH in throughfall and precipitation. The ammonium/nitrate ratio in throughfall decreases with distance from the quarry though monitoring of NH3 and NO2 concentrations in the air with passive samplers shows the opposite trend. These findings support the theory of discrimination against NH3 in dry deposition due to the presence of Ca2+ particles on leaf surfaces resulting from limestone aerosols. Higher sulfate deposition near the quarry is consistent with higher atmospheric SO2 concentrations and co-deposition between calcium and sulfate.