[Analysis on the Characteristics of Oxidation Potential and Influence Sources of PM in Baoding City in Winter].

In order to explore the characteristics of PM oxidation potential and its impact sources in the suburbs of Baoding City in the winter of 2018, the dithiothreitol (DTT) method was used to determine the reactive oxygen species in PM. Pearson correlation was used to analyze the relationship between the chemical components in PM and the oxidation potential. PMF was used to analyze the pollution source of DTT. Firstly, the results showed that the average value of (PM) in Baoding in winter was (140.96±70.67) μg·m higher than the concentration of PM in Beijing during the same period. Secondly, both the DTT and DTT values of the oxidation potential were higher during the day than those at night[DTT was (2.37±0.76) nmol·(min·m) during the day and (2.14±1.17) nmol·(min·m) at night; DTT was (0.96±0.60) pmol·(min·μg) during the day and (0.76±0.41) pmol·(min·μg) at night]. This showed that the atmospheric environment during the day was more conducive to the generation and survival of active oxygen. In addition, through the analysis of the correlation between DTT and carbohydrates, inorganic salt ions, OC, EC, and water-soluble metals, it was found that metal Fe, oxalate, and NH had a high correlation with DTT both day and night (during the day:=0.790, <0.01, at night:=0.960, <0.01; during the day:=0.609, <0.01, at night:=0.577, <0.01; during the day:=0.627, <0.01, at night:=0.586, <0.01), and OC, levoglucan, mannan, and galactan were only highly correlated with DTT in the daytime (=0.675, <0.01; =0.701, <0.01; =0.662, <0.01; =0.671, <0.01). Finally, according to the PMF source analysis, there were five main pollution sources that affected DTT:secondary sources (29.9%), biomass combustion (29.2%), dust (11.2%), mineral dust and industrial sources (8.6%), and traffic sources (21.1%). The influence of secondary sources and biomass combustion on DTT was dominant.