Numerous toxicological studies have highlighted the association between urban particulate matter (PM) and increased respiratory infections and lung diseases. The adverse impact on the lungs is directly linked to the complex composition of particulate matter, initiating reactive oxygen species (ROS) production and consequent lipid peroxidation. Excessive ROS, particularly within mitochondria, can destroy subcellular organelles through various pathways. In this study, we confirmed the induction of ferroptosis, an iron-dependent cell death, upon exposure to an urban PM using RT-qPCR and signaling pathway analysis. We used KRISS CRM 109-02-004, the certified reference material for the analysis of particulate matter, produced by the Korea Research Institute of Standards and Science (KRISS). To validate that ferroptosis causes lung endothelial toxicity, we assessed intracellular mitochondrial potential, ROS overproduction, lipid peroxidation, and specific ferroptosis biomarkers. Following exposure to the urban PM, a significant increase in ROS generation and a decrease in mitochondrial potential were observed. Furthermore, it induced hallmarks of ferroptosis, including the accumulation of lipid peroxidation, the loss of antioxidant defenses, and cellular iron accumulation. In addition, the occurrence of oxidative stress as a key feature of ferroptosis was confirmed by increased expression levels of specific oxidative stress markers such as NQO1, CYP1B1, FTH1, SOD2, and NRF. Finally, a significant increase in key ferroptosis markers was observed, including xCT/SLC7A11, NQO1, TRIM16, HMOX-1, FTL, FTH1, CYP1B1, CHAC1, and GPX4. This provides evidence that elevated ROS levels induce oxidative stress, which ultimately triggers ferroptosis. In conclusion, our results show that the urban PM, KRISS CRM, induces cellular and mitochondrial ROS production, leading to oxidative stress and subsequent ferroptosis. These results suggest that it may induce ferroptosis through ROS generation and may offer potential strategies for the treatment of lung diseases.

Accurate measurement of hazardous elements in cosmetics is considerably important in response to cosmetic safety issues. A sample preparation method using microwave-assisted acid digestion combined with double isotope dilution inductively coupled plasma/mass spectrometry (ID ICP-MS) was used for the certification of the hazardous elements, Cd, Hg and Pb, in cosmetic powder samples. The HF-free sample preparation method was validated and applied to analyse Cd and Pb in cosmetic powder. The Hg content in the sample was determined by employing a fast valve sample introduction system to resolve the severe memory effect in Hg analysis. Homogeneity and stability were also evaluated. The certified values of Cd, Hg and Pb were (24.8 ± 1.3) mg kg⁻¹, (0.648 ± 0.065) mg kg⁻¹ and (24.55 ± 0.31) mg kg⁻¹, respectively. The relative combined standard uncertainty was 2.7% for Cd, 5.1% for Hg and 0.62% for Pb. The detailed procedure for certification and evaluation of the associated uncertainty is also presented. The proper use of the developed CRM for quality control and method validation in testing laboratories and the cosmetic industry is expected to significantly improve the reliability and quality of test results for hazardous elements in cosmetics, thereby contributing to cosmetic safety.

We report comprehensive elemental composition studies on the average urban airborne particulate matters (PMs) collected in the Greater Seoul area, Korea, in 2019 to identify regional and chronological characteristics of the sample as a candidate for certified reference material (CRM), using k₀-based single comparator instrumental neutron activation analysis (k₀-INAA). The method was successfully validated by comparing the analysis result of a similar matrix CRM (SRM 1648a urban particulate matter) of National Institute of Standards and Technology, USA, with corresponding certified values. The same methodology was applied to determine various elements in candidate environmental materials for future CRM development, including the urban PMs and incineration ashes, to investigate the possibility of using k₀-INAA for certification of relevant reference materials. In total, 46 elements in the urban PM sample were analyzed and their concentration levels were compared with the urban PMs collected in the 1970s in St. Louis, USA. Urban PMs of Korea Research Institute of Standards and Science in 2019 contain significantly lower levels of hazardous elements, such as As, Cd, Cr, Hg, and Pb, as compared to those of the 1970s, which can be attributed to the reduced air pollution by environmental regulation and technological innovation. The potential major source of urban airborne PMs was also discussed.

An international comparison study on the accurate determination of the molar mass M (Si) of silicon artificially enriched in ²⁸ Si ( x ( ²⁸ Si) > 0.9999 mol mol ⁻¹ ) has been completed. The measurements were part of the high level CCQM-P160 pilot study assessing the ability of National Metrology Institutes (NMIs) and Designated Institutes (DIs) to make such measurements at the lowest possible levels of measurement uncertainty and to identify possible difficulties when measuring this kind of sample. This study supports the molar mass measurements critical to disseminating the silicon route to realizing the new definitions for the kilogram and the mole. Measurements were also made by one external research institute and an external company. The different institutes were free to choose their experimental (mass spectrometric) set-ups and equipment, thereby enabling also the comparison of different techniques. The investigated material was a chemically pure, polycrystalline silicon material. The subsequent modified single crystalline secondary product of this material was intended for the production of silicon which was used for two additional spheres in the context of the redetermination of the Avogadro constant N _A , required for the revision of the International System of Units (SI) via fundamental constants which came into force from May 2019. The CCQM pilot study was organized by Physikalisch-Technische Bundesanstalt (PTB). Aqueous silicon solutions were shipped to all participating institutions. The data analysis as well as the uncertainty modelling and calculation of the results was predefined. The participants were provided with an uncertainty budget as a GUM Workbench ^® file as well as a free software license for the duration of the comparison. The agreement of the values of the molar mass ( M (Si) = 27.976 942 577 g mol ⁻¹ ) was excellent with ten out of 11 results reported within the range of relative uncertainty of 1 × 10 ⁻⁸ required for the revision of the SI.