Oxidative Potential Characterization of Different PM 2.5 Sources and Components in Beijing and the Surrounding Region.

With the implementation of air pollution control measures, the concentration of air pollutants in the North China Plain has exhibited a downward trend, but severe fine particulate matter (PM) pollution remains. PM is harmful to human health, and the exploration of its source characteristics and potential hazards has become the key to mitigating PM pollution. In this study, PM samples were collected in Beijing and Gucheng during the summer of 2019. PM components, its oxidative potential (OP), and health risks were characterized. The average PM concentrations in Beijing and Gucheng during the sampling period were 34.0 ± 6.1 μg/m and 37.1 ± 6.9 μg/m, respectively. The principal component analysis (PCA) results indicated that the main sources of PM in Beijing were vehicle exhaust and secondary components and that the main sources in Gucheng were industrial emissions, dust and biomass combustion. The OP values were 91.6 ± 42.1 and 82.2 ± 47.1 pmol/(min·m), respectively, at these two sites. The correlation between the chemical components and the OP values varied with the PM sources at these two locations. The health risk assessment results demonstrated that Cr and As were potentially carcinogenic to all populations at both sites, and Cd posed a potential carcinogenic risk for adults in Gucheng. Regional cooperation regarding air pollution control must be strengthened to further reduce PM pollution and its adverse health effects.