Characterization and source apportionment of oxidative potential of ambient PM_2.5 in Nanjing, a megacity of Eastern China

ABSTRACT

Oxidative potential (OP) reflects integratedtoxicity of PM_2.5. Therefore, OP of PM_2.5 samples collected from traditional central and suburban areas (Gulou and Xianlin) in Nanjing, a megacity of China, from Jan. 2020 to Jun. 2021 was analyzed by using two abiotic assays, DTT and AA assays (OP^DTT and OP^AA). Values of OP^DTTv and OP^AAv were  0.82 ~ 3.82  and    0.15 ~ 2.22 nmol/min/m³, respectively. The OP values of PM_2.5 samples collected from the Xianlin were higher than those from the Gulou by using both the DTT assay and the AA assay in this study, suggesting the seasonal and spatial variation. Moreover, OP values analyzed by using DTT assay were higher than those by using AA assay. Based on Positive Matrix Factorization (PMF), the major pollution source of the OP of PM_2.5 in Nanjing was combustion source. This study may be helpful for evaluating adverse health risks of PM_2.5 in a megacity.

KEYWORDS:

• Oxidative potential
• PM_2.5
• seasonal variation
• spatial variation
• positive matrix factorization

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

All data reported here can be made available on request

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [2018YFC1800603]; National Natural Science Foundation of China [21874065 and 22176085].