High-resolution observation per 1.5 h revealed prominent time-dependent daily contamination variations of p-phenylenediamine (PPD) antioxidants and their quinone derivatives PPDQs in PM2.5 from central China

• Zifang PengZhengzhou University
• Shijiao HouZhengzhou University
• Qingyun HeZhengzhou University
• Fangcheng SuZhengzhou University
• Liang RenHenan University of Chinese Medicine
• Congcong PeiZhengzhou University
• Dan YinZhengzhou University
• Yanhao ZhangHong Kong Baptist University
• Yanjie HuangHenan University of Chinese Medicine
• Shusheng ZhangZhengzhou University
• Zongwei CaiHong Kong Baptist University