Newer Generation of Scooters: Polychlorinated Dibenzo-p-dioxin and Dibenzofuran and Polychlorinated Biphenyl Reductions
| Autor: | Hsi-Hsien Yang, Lin-Chi Wang, Yen-Kung Hsieh, Yun Hwei Shen, Sheng-Lun Lin, Jheng-Hong Chen, Jau-Huai Lu, Chia-Fon Lee |
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| Rok vydání: | 2020 |
| Předmět: |
Pollutant
010504 meteorology & atmospheric sciences Feedback control Direct effects Polychlorinated biphenyl 01 natural sciences Pollution law.invention Dibenzofuran chemistry.chemical_compound Congener chemistry law Environmental chemistry Catalytic converter Environmental Chemistry Environmental science Dibenzo-p-dioxin 0105 earth and related environmental sciences |
| Zdroj: | Aerosol and Air Quality Research. 20:1495-1509 |
| ISSN: | 2071-1409 1680-8584 |
| DOI: | 10.4209/aaqr.2020.04.0138 |
| Popis: | 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 Nm-3 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. |
| Databáze: | OpenAIRE |
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