Jheng-Hong Chen1, Yun-Hwei Shen1, Hsi-Hsien Yang This email address is being protected from spambots. You need JavaScript enabled to view it.2, Jau-Huai Lu3, Lin-Chi Wang 4, Yen-Kung Hsieh This email address is being protected from spambots. You need JavaScript enabled to view it.5, Chia-Fon Lee6, Sheng-Lun Lin 7,8

Department of Resources Engineering, National Cheng Kung University, Tainan 70101, Taiwan
Department of Environmental Engineering and Management, Chaoyang University of Technology, Taichung 41349, Taiwan
Department of Mechanical Engineering, National Chung Hsing University, Taichung 40254, Taiwan
Department of Environmental Engineering, Chung Yuan Christian University, Taoyuan 32023, Taiwan
Marine Ecology and Conservation Research Center, National Academy of Marine Research, Kaohsiung 80661, Taiwan
Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, IL 61801, USA
Department of Civil Engineering and Geomatics, Cheng Shiu University, Kaohsiung 83347, Taiwan
Center for Environmental Toxin and Emerging-Contaminant Research, Cheng Shiu University, Kaohsiung 83347, Taiwan

Received: April 10, 2020
Revised: April 21, 2020
Accepted: April 21, 2020

Download Citation: ||https://doi.org/10.4209/aaqr.2020.04.0138 

Cite this article:

Chen, J.H., Shen, Y.H., Yang, H.H., Lu, J.H., Wang, L.C., Hsieh, Y.K., Lee, C.F. and Lin, S.L. (2020). Newer Generation of Scooters: Polychlorinated Dibenzo-p-dioxin and Dibenzofuran and Polychlorinated Biphenyl Reductions. Aerosol Air Qual. Res., https://doi.org/10.4209/aaqr.2020.04.0138


  • PCDD/F and PCB could be reduced with the improvement of regulated pollutant emissions.
  • Replacing carburetor by electronic fuel injection reduced > 95% PCDD/F and PCB emissions.
  • Tailpipe renew effectively reduces 60.0–93.8% PCDD/Fs and 85.3–97.7% PCB emissions.
  • The annual TEQ emissions could be reduced 99.7% by replacing all scooters to Tier 6.


Scooter emissions have attracted attention in recent years because of human exposure to their direct effects in urban areas. Trace toxics, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) have thus become important in scooter emissions. In this work, ten Tier 5 and 6 scooters were tested using a 100-second model to analyze their PCDD/F and PCB emissions and compare the results with previous Tier 3 studies. Tier 5 and 6 scooters emitted 1.86–2.91 and 0.133–0.298 pg WHO-TEQ Nm3 of PCDD/Fs and PCBs, respectively. It was interesting to find that the PCDD/Fs were reduced by 94.6–97.4% and 99.4–99.6% in Tier 5 and 6 motors, respectively. The congener profiles of PCDD/Fs were affected by improving the emission control. The domination of highly chlorinated congeners shown in Tier 3 was reduced in Tier 5 with increases in low chlorinated PCDFs. This showed that de novo synthesis occurred and could be inhibited by the OBD system in Tier 6. The tailpipe renews reduced 60.0–93.8% of PCDD/Fs and 85.3–97.7% of PCB emissions, but several cases would still exhibit a delay for stable operation of a catalytic converter. The annual emissions of PCDD/F TEQ was calculated based on the statistics in 2019 and tested as 1.63 g WHO-TEQ. It could be 99.7% reduced to 3.55 mg by replacing all scooters with Tier 6. Consequently, the improvement of electronic fuel injection and on-board diagnostics systems from a carburetor without feedback control not only reduced the regulated pollutants but effectively reduced PCDD/F emissions.

Keywords: Scooter; PCDD/Fs; PCBs; Electronic fuel injection; on-board diagnostics; Carburetor; Emission standards.

Impact Factor: 2.735

5-Year Impact Factor: 2.827

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