Oxidative potential of PM10 and PM2.5 collected at high air pollution site related to chemical composition: Krakow case study

Measurements of the oxidative potential (OP) of airborne particulate matter may be applied for the assessment of the health-based exposure by integrating various biologically relevant properties of particles. This study aimed at the determination of oxidative activity of two size fractions of particulate using the ascorbic acid (AA) and reduced glutathione (GSH) assay. Samples of PM were collected in Krakow, one of the most polluted cities in Poland, in the city centre. Samples were collected during wintertime, when heating sources used in residential areas have significant influence on the concentrations of particulate matter in the air. PM10 and PM2.5 concentrations varied from 8.9 to 92.5 μg m^?3. Samples were chemically analysed for elemental carbon, organic carbon, ions and metals. PM2.5 was found as a more oxidative active fraction, where OP_AA and OP_GSH depletions were up to 81.7 and 132.0 μg m^?3, respectively. The average values of OP_AA of PM10 and PM2.5 were similar and equalled 40.8 and 37.2 μg m^?3, respectively. The average value of OP_GSH of PM2.5 equalled 56.7 μg m^?3 and was 3.5 times higher than OP_GSH of PM10. The loss of AA amount in PM10 and PM2.5 and the depletion of GSH in PM2.5 were best described by the pseudo second-order kinetics model. The kinetics of the GSH depletion reaction in PM10 was best described by the pseudo first-order kinetics model. The strong correlations between carbonaceous and metallic constituents of PM and oxidative potential suggest their relevance in participation in oxidative activity of particulate matter.