Jen-Hsiung Tsai1, Shui-Jen Chen This email address is being protected from spambots. You need JavaScript enabled to view it.1, Sheng-Lun Lin2,3, Zheng-You Xu1, Kuo-Lin Huang1, Chih-Chung Lin1 

1 Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan
2 School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
3 Center for Environmental Toxin and Emerging-contaminant Research, Cheng Shiu University, Kaohsiung 83347, Taiwan

Received: November 16, 2020
Revised: February 4, 2021
Accepted: February 5, 2021

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

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Tsai, J.H., Chen, S.J., Lin, S.L., Xu, Z.Y., Huang, K.L., Lin, C.C. (2021). Chemical Characterization of Water-soluble Ions and Metals in Particulate Matter Generated by a Portable Two-stroke Gasoline Engine. Aerosol Air Qual. Res. 21, 200632.


  • Chemical characterization of a portable two-stroke gasoline engine was studied.
  • The dominant water-soluble ion species on the PM were Ca2+, Na+, and SO42–.
  • The A/C ratios increased with the engine load but were all less than 0.5.
  • The major metals among the 21 analyzed metals were Ca, Na, K, Al, Fe, Mg, and Zn.


To examine the characteristics of water-soluble ions and metals on the particulate matter (PM) in the exhausts, a P2SGE (portable two-stroke gasoline engine) was fueled by unleaded gasoline #92 blended with different two-stroke engine oil brands (CPC Super Low Smoke Two-Stork Engine Oil (SLS), CPC Low Smoke Two-Stroke Engine Oil (LS), and MERCURY STAR (MS)) and operated under idling, mid-load (1.5 kW), and high-load (1.9 kW), respectively. Experimental results reveal that the PM mass concentrations in the exhausts were in the order MS (avg. 1,934 mg Nm–3) > SLS (avg. 1,543 mg Nm–3) > LS (avg. 1,167 mg Nm–3) in all test conditions. The mass concentrations and emission factors (EFs) of PM decreased as the P2SGE load increased by adding each tested lubricant. Based on fuel consumption, EFs of ΣIons were the lowest when utilizing the LS additive (avg. 89.7 mg L-fuel–1), followed by the MS and SLS (165 and 168 mg L-fuel–1, in average, respectively); whereas the lowest levels of ΣMetals were observed by using MS additive (avg. 61.3 mg L–1), followed by using the LS (avg. 83.8 mg L–1) and SLS (avg. 85.2 mg L–1). The soluble ions on the PM were mostly Na+, Ca2+, NO3, and SO42– among eight tested species, which accounted for only 0.05–0.19% (avg. 0.1%) of PM mass. The 21 analyzed metal components represented only 0.05% of the mass of the PM, and were dominated by Na, Mg, Al, K, Ca, Fe, and Zn, which represented 98.7% by mass of ΣMetals. Our finding for portable engine emission has been rarely considered in the literature but it is unneglectable for labors who are usually exposed to the ions and metals. Further health risk assessment research is suggested to include temporarily real-life exposures with high pollutant levels.

Keywords: Portable two-stroke gasoline engine, Particulate matter, Water-soluble ions, Metals, Environmental pollution

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