Determination of oxidative properties of ambient particulate matter based on ascorbic acid

Abstract

Oxidative properties of different particulate matter samples were analyzed using an approach based on oxidation of ascorbate. Therefore aliquots of the samples were incubated with a buffer solution imitating the RELF (respiratory extracellular lining fluid) containing ascorbic acid. The depletion of ascorbic acid was determined using reversed phase liquid chromatography and an UV detector. The measurements were done with different ambient and indoor air samples collected within a variety of projects or within the ambient air sampling networks of provincial governments, originating from Vienna, Styria, Carinthia, Upper Austria, and Slovenia. The sampling stations of urban air samples can be separated in urban, urban-background, and background stations. Furthermore emission samples containing particulate matter that was formed during combustion processes was analyzed. Those oxidative properties were compared with the chemical composition of the particulate matter samples (with a main focus on ions, and metals typically originating from mineral dust) as well as carbon parameters and source distributions. Clearest trends were seen for carbon parameters, with higher concentrations leading to increased depletion of ascorbate.