Heavy metals are defined as metals with relatively high density and atomic weight, and their various applications have raised serious concerns about the environmental impacts and potential human health effects. Chromium is an important heavy metal that is involved in biological metabolism, but Cr exposure can induce a severe impact on occupational workers or public health. In this study, we explore the toxic effects of Cr exposure through three exposure routes: dermal contact, inhalation, and ingestion. We propose the underlying toxicity mechanisms of Cr exposure based on transcriptomic data and various bioinformatic tools. Our study provides a comprehensive understanding of the toxicity mechanisms of different Cr exposure routes by diverse bioinformatics analyses.

Residential radon exposure and cigarette smoking are the two most important risk factors for lung cancer. The combined effects thereof were evaluated in a multi-center matched case-control study in South Korea. A total of 1038 participants were included, comprising 519 non-small cell lung cancer cases and 519 age- and sex- matched community-based controls. Residential radon levels were measured for all participants. Multivariate logistic regression was used to calculate odds ratios (OR) for lung cancer according to radon exposure (high ≥ 100 Bq/m³ vs. low < 100 Bq/m³), smoking status, and combinations of the two after adjusting for age, sex, indoor hours, and other housing information. The median age of the participants was 64 years, and 51.3% were women. The adjusted ORs (95% confidence intervals [CIs]) for high radon and cigarette smoking were 1.56 (1.03–2.37) and 2.53 (1.60–3.99), respectively. When stratified according to combinations of radon exposure and smoking status, the adjusted ORs (95% CIs) for lung cancer in high-radon non-smokers, low-radon smokers, and high-radon smokers were 1.40 (0.81–2.43), 2.42 (1.49–3.92), and 4.27 (2.14–8.52), respectively, with reference to low-radon non-smokers. Both residential radon and cigarette smoking were associated with increased odds for lung cancer, and the difference in ORs according to radon exposure was much greater in smokers than in non-smokers.

Formaldehyde is a colorless, pungent, highly reactive, and toxic environmental pollutant used in various industries and products. Inhaled formaldehyde is a human and animal carcinogen that causes genotoxicity, such as reactive oxygen species formation and DNA damage. This study aimed to identify the toxic effects of inhaled formaldehyde through an integrated toxicogenomic approach utilizing database information. Microarray datasets (GSE7002 and GSE23179) were collected from the Gene Expression Omnibus database, and differentially expressed genes were identified. The network analyses led to the construction of the respiratory system-related biological network associated with formaldehyde exposure, and six upregulated hub genes (AREG, CXCL2, HMOX1, PLAUR, PTGS2, and TIMP1) were identified. The expression levels of these genes were verified via qRT-PCR in 3D reconstructed human airway tissues exposed to aerosolized formaldehyde. Furthermore, NRARP was newly found as a potential gene associated with the respiratory and carcinogenic effects of formaldehyde by comparison with human in vivo and in vitro formaldehyde-exposure data. This study improves the understanding of the toxic mechanism of formaldehyde and suggests a more applicable analytic pipeline for predicting the toxic effects of inhaled toxicants.

The study investigated PM_2.5 and heavy metal pollutant concentrations in Seoul and Wonju, South Korea, emphasizing the importance of considering PM_2.5 chemical constituents for health impact assessments. While PM_2.5 concentrations were similar between the two cities with slight variations, heavy metal concentrations differed significantly. Regional sources, PM_2.5 composition, and meteorological conditions influenced these variations. Exposure to Fe was highest in all areas, with some heavy metals exceeding permissible levels, stressing the need to consider regional characteristics in assessments. Different heavy metals influence health risks differently in each city. When examining the HI (the summation of the hazard quotient for heavy metals), Seoul remained below an HI value of 1, while Wonju exceeded this threshold when exposed to CTE concentrations. In Seoul, As had a significant health impact of PM_2.5, while in Wonju, Mn was more influential. Source apportionment confirmed different pollution sources in Seoul and Wonju, affecting the distribution of PM_2.5 constituents in the atmosphere. Effective PM_2.5 management requires a comprehensive approach considering chemical constituents and health impacts not just mass-based PM_2.5 management, emphasizing regional-specific assessments and policy considerations to mitigate health risks. Therefore, tailored management strategies based on regional characteristics are necessary. Graphical Abstract

Currently, low-cost, sensor-based fine dust measurement devices are commercially available in South Korea. This study evaluated the reliability of three such devices—Yi Shan A4, Plantower PMS7003, and Plantower PMS7003—in comparison to long-term consecutive monitoring systems for discharge and prevention facilities regarding fine dust control. The performance of these devices for concentration intervals over time was examined through real-time comparison using a GRIMM (Model: 11-A, dust spectrometer from Grimm Technologies) as a reference; this included a correction factor (C-Factor), calculated by a gravimetric method and an equivalence test. For comparison, the reference and target devices were installed in a chamber with fine dust concentrations of 2 µg/m³, with temperature and humidity maintained at 20 °C and 40%, respectively. The fine particulate matter (PM)_2.5 concentrations were classified into five intervals: ≤40 µg/m³, 40–80 µg/m³, 80–120 µg/m³, 120–160 µg/m³, and 200–230 µg/m³. Statistical analysis was performed using data obtained from national stations for monitoring and controlling fine dust released from facilities under high fine dust loading conditions. The results showed that the measurements of all target devices, which were corrected according to the reference device, provided accurate values at PM_2.5 concentrations of ≥40 µg/m³. The statistical analysis results suggest that the evaluated devices are more reliable than the conventional numerical-analysis-based monitoring system