Beyond Substituted p-Phenylenediamine Antioxidants: Prevalence of Their Quinone Derivatives in PM2.5

Wei Wang, Guodong Cao, Jing Zhang, Pengfei Wu, Yanyan Chen, Zhifeng Chen, Zenghua Qi, Ruijin Li, Chuan Dong, Zongwei Cai*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

42 Citations (Scopus)


Substituted para-phenylenediamine (PPD) antioxidants have been extensively used to retard oxidative degradation of tire rubber and were found to pervade multiple environmental compartments. However, there is a paucity of research on the environmental occurrences of their transformation products. In this study, we revealed the co-occurrence of six PPD-derived quinones (PPD-Qs) along with eight PPDs in fine particulate matter (PM2.5) from two Chinese megacities, in which N,N′-bis(1,4-dimethylpentyl)-p-phenylenediamine quinone (77PD-Q) was identified and quantified for the first time. Prevalent occurrences of these emerging PPD-Qs were found in Taiyuan (5.59–8480 pg/m3) and Guangzhou (3.61–4490 pg/m3). Significantly higher levels of PPDs/PPD-Qs were observed at a roadside site, implying the possible contribution of vehicle emissions. Correlation analysis implied potential consistencies in the fate of these PPD-Qs and suggested that most of them were originated from the transformation of their parent PPDs. For different subpopulation groups under different exposure scenarios, the estimated daily intakes of PPD-Qs (0.16–1.25 ng kgbw–1 day–1) were comparable to those of their parent PPDs (0.19–1.41 ng kgbw–1 day–1), suggesting an important but overlooked exposure caused by novel PPD-Qs. Given the prolonged exposure of these antioxidants and their quinone derivatives to traffic-relevant occupations, further investigations on their toxicological and epidemiological effects are necessary.

Original languageEnglish
Pages (from-to)10629–10637
Number of pages9
JournalEnvironmental Science and Technology
Issue number15
Early online date14 Jul 2022
Publication statusPublished - 2 Aug 2022

Scopus Subject Areas

  • Chemistry(all)
  • Environmental Chemistry

User-Defined Keywords

  • airborne quinones
  • fine particulate matter
  • human inhalation exposure
  • para-phenylenediamine derivatives
  • tire rubber additives


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