Pollution sources affecting the oxidative potential of fine aerosols in a Portuguese urban-industrial area - an exploratory study

This study targets to determine the oxidative potential (OP) of fine aerosols in an urban-industrial area of the Lisbon Metropolitan Area (Portugal) and, in addition, to identify which pollution sources may have an impact on the OP levels of fine aerosols. For this purpose, thirty samples were selected from a set of 128 samples collected over one year (Dec 2019-Nov 2020), based on the highest load for each source (both mass and OP_V^DTT ) showed to have a significant positive association with PM2.5 levels (R2 = 0.714). Considering that the mass contributions of the different sources to the PM2.5 levels were known, Spearman correlations were assessed and significant correlations were found between OP_V^DTT and three different sources: vehicle exhaust (ρ = 0.647, p-value = 0.001), fuel-oil combustion (ρ = 0.523, p-value = 0.012) and industry (ρ = 0.463, p-value = 0.018). Using a multiple linear regression analysis, these three sources were found to explain 82 OP_V^DTT , with vehicle exhaust being the most influential source.