New nanoparticles found in aircraft exhaust
Regarding the retraction of an article due to analytical errors (July 29, 2026)
The authors have retracted the article, featured in this press release, because the authors discovered critical errors in the experiments described in the article. Consequently, the research findings described in this press release are no longer considered valid scientific knowledge.
After the publication, the authors received comments at a scientific meeting that onion-like carbon particles might be formed during the production of carbon films used for transmission electron microscopy (TEM) analysis. The authors conducted validation experiments, including reanalysis of the TEM samples used in the study, and identified a significant number of onion-like particles and trace particles in the blank samples. Consequently, it became difficult to conclude that the onion-like particles and trace particles originated from the jet engine exhaust, which was one of the major findings of this study.
We deeply apologize to all parties for the wrong conclusions drawn from the analytical errors.
Retraction Notice: https://doi.org/10.1021/acsestair.6c00248
Original article:
A multi-national research team from the National Institute for Environmental Studies, Zurich University of Applied Sciences, Tokyo Metropolitan University, and other institutions (hereinafter referred to as “our research team”) conducted emission tests on aircraft engines and examined the shapes and internal structures of the exhaust particles with high-resolution transmission electron microscopy. Our research team identified novel onion-like (multiple concentric spherical crystal layered) particles and amorphous (non-crystalline) particles, in addition to the well-known soot in the aircraft engine exhausts. The exhaust particles were typically very small (approximately 10–20 nm in diameter) and single spherical particles. Although the detailed physicochemical properties of the onion-like particles are currently unknown, their behaviors in the atmosphere and in the body may be different from other particles. Therefore, further research is required to assess their potential impacts on climate and health. The related research paper has been published in ACS ES&T Air, a journal in the field of atmospheric sciences, by the American Chemical Society (ACS), on 8 April 2025.