EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Oxidative Potential and Chemical Characteristics of Ambient PM2.5 in Guangzhou, China

Peng Cheng1, Manman Zhang2, and Yongjie Li3
Peng Cheng et al.
  • 1Institute of Mass Spectrometer and Atmospheric Environment, Jinan University, Guangzhou, China (
  • 2Department of Pharmacy, Henan University of Chinese Medicine, Zhengzhou, China (
  • 3Department of Civil and Environmental Engineering, University of Macau, Macau, China (

The dithiothreitol (DTT) assay is widely used to characterize the Oxidation Potential (OP) of atmospheric particulate matter (PM), which can cause adverse effects on human health. However, it’s under debate which chemical species determines the consumption rate of DTT. During January and April 2018, we measured the improved DTT assay of daily PM2.5 samples collected in Guangzhou, China with complimentary measurements of water-soluble ions, organic/elemental carbon (OC/EC) and metal elements. The average sampled air volume normalized consumption rate of DTT (DTTv) was 4.67 ±1.06 and 4.45 ± 1.02 nmol min-1 m-3, in January and April, respectively while the average PM2.5 mass normalized consumption rate of DTT (DTTm) was 13.47 ± 3.86 and 14.66 ± 4.49 pmol min-1 μg-1. Good correlations were found between DTTv and concentration of PM2.5, OC, and EC while no correlation was found between DTTm and concentrations of water-soluble ions, OC, EC or metal element, which is consistent with most early observations. We also evaluated the contribution of soluble metals to DTT assay by addition of EDTA, a strong metal chelator. We found that nearly 90% of DTTv and DTTm were reduced by EDTA, suggesting a dominant role of soluble metals in determining the response of DTT to ambient PM2.5. Based on responses of DTT to soluble metals in literature, we found that Cu(II) and Mn(II) are the major contributors to OP of PM2.5 in Guangzhou. The correlation coefficient between DTTm and OC shows a clear increase after addition of EDTA, implying that the response of DTT to quinones is not strongly suppressed by EDTA.

How to cite: Cheng, P., Zhang, M., and Li, Y.: Oxidative Potential and Chemical Characteristics of Ambient PM2.5 in Guangzhou, China, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12389,, 2020


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