• Metal-composite filaments emit more than twice the amount of nanoparticles, raising concerns over inhalation exposure
  

• Research published in the Journal of Hazardous Materials (Top 4.9% in the environmental field, IF 11.3)

A schematic overview of the study. When using PLA-Steel filament, quantitative and qualitative analysis showed that the emitted nanoparticles were metal-oxide particles containing hematite.

The research team led by Prof. Jong-Sang Yoon of the Department of Energy & Environmental Engineering (Air Quality Research Lab.) at The Catholic University of Korea, in joint research with Prof. Ki-Joon Jeon of the Department of Environmental Engineering at Inha University, experimentally demonstrated for the first time worldwide that metal-oxide nanoparticles can be released into the air during 3D printing. Master’s program student Eun-Jin Park from the Department of Energy & Environmental Engineering participated as the first author. The research findings were published in the Journal of Hazardous Materials, a journal ranked in the top 4.9% in the environmental field with an impact factor of 11.3.

Although 3D printing technology is widely used in industrial, household, and educational settings, concerns continue to be raised regarding potential human health and environmental impacts caused by ultrafine and nanoscale particles emitted during the printing process. Previous studies have mainly focused on common plastic filaments such as PLA and ABS, leaving the risks associated with metal-composite filaments insufficiently understood.

Prof. Yoon’s team used PLA filament containing stainless steel to quantitatively and qualitatively analyze the physical and chemical characteristics of nanoparticles emitted during printing. The results showed that particles in the tens-of-nanometers range were released at more than twice the amount compared to general PLA filament.

Electron microscopy analysis revealed distinctive flake-shaped particles, which were identified as metal-oxide nanoparticles rich in α-Fe2O3 (hematite). The research team explained that such particles, when inhaled, may pose potential toxicity and health risks.

Prof. Jong-Sang Yoon stated, “This study will serve as foundational data for various follow-up studies such as toxicity assessment, environmental exposure modeling, and the establishment of indoor workplace management guidelines. It is also expected to contribute to the development of public safety guidelines and indoor environmental safety standards.”

The study led by Prof. Yoon’s research team was conducted with the support of the IITP Integrated Bachelor-Master ICT Talent Training Program (IITP-2025-RS-2024-00438207) and the National Research Foundation of Korea Basic Research Program (RS-2023-00250272).