Publications by authors named "Seunghun Ryu"

Article Synopsis
  • - The study evaluates the health risks associated with CMIT and MIT, commonly found in disinfectants, by examining their effects on the respiratory system in animal models.
  • - Researchers used radiolabeled compounds and advanced techniques to observe significant retention of CMIT/MIT in lung tissue and identified metabolites linked to potential toxicity.
  • - Findings suggest that CMIT/MIT can bind to important biological molecules, leading to irreversible damage and oxidative stress, emphasizing the need for stricter safety measures regarding these chemicals.
View Article and Find Full Text PDF

This study aims to characterize levels of molds, bacteria, and environmental pollutants, identify the associations between indoor mold and dampness exposures and childhood allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, using three different exposure assessment tools. A total of 50 children with their parents who registered in Seoul and Gyeonggi-do in Korea participated in this study. We collated the information on demographic and housing characteristics, environmental conditions, and lifestyle factors using the Korean version of the International Study of Asthma and Allergies in Childhood questionnaire.

View Article and Find Full Text PDF
Article Synopsis
  • - Benzylalkyldimethylammonium chloride (BAC) is a quaternary ammonium compound widely used for its antimicrobial properties, especially in products created since the COVID-19 outbreak.
  • - The study performed on male Sprague Dawley rats revealed significant uptake of BAC in respiratory and other internal organs, highlighting potential toxic effects due to inhalation exposure.
  • - Using quantitative whole-body autoradiography, researchers found that a small percentage of BAC remained in the rats long after administration, suggesting a need for further assessment of its impact in living organisms.
View Article and Find Full Text PDF
Article Synopsis
  • A study was conducted to investigate whether isothiazolinone biocides (CMIT and MIT) could cause lung injuries when introduced into the body via intratracheal and intranasal methods.
  • The researchers found that CMIT/MIT rapidly distributed throughout the respiratory tract, and significant amounts of the substances reached the lungs, causing detectable damage and inflammation.
  • The results indicated that intratracheal instillation led to greater lung injuries compared to intranasal exposure, suggesting varying levels of toxicity based on administration route.*
View Article and Find Full Text PDF

In April 2011, the Korea Centers for Disease Control and Prevention (CDC) announced the results of an epidemiological investigation that an unknown cause of lung disease that occurred throughout Korea was caused by humidifier disinfectants. The unprecedented social catastrophe caused by humidifier disinfectants, a household chemical, has so far reported 1,784 deaths and 5,984 survivors in South Korea. This study was designed to investigate the multi-layer relationships between psychological symptoms and adaptive functioning in survivors of the Humidifier disinfectants in South Korea caused by chemical toxic substances.

View Article and Find Full Text PDF

This study aimed to compare the psychological symptoms of humidifier disinfectant survivors to the general population and explore socio-demographic factors influencing survivors' psychological symptoms. A one-way Multivariate Analysis of Covariance (MANCOVA) and a series of two-way MANCOVA were conducted with a sample of 228 humidifier disinfectant survivors and 228 controls. The results demonstrated that the survivor group displayed higher anxious/depressed symptoms, withdrawn symptoms, somatic complaints, thought problems, attention problems, aggressive behavior and rule-breaking behavior than the general group.

View Article and Find Full Text PDF

This study aimed to quantify both chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) dissolved in different product brands and to characterize the exposure to these chemicals among humidifier disinfectant-associated lung injury (HDLI) patients. Both CMIT and MIT dissolved in different humidifier disinfectant (HD) products were quantified using gas chromatography-mass spectrometry. The inhalation level of CMIT and MIT was estimated based on HD-associated factors as reported by HDLI patients.

View Article and Find Full Text PDF

A mixture of 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT) had been used as an active ingredient in humidifier disinfectants (HDs). Owing to its high reactivity, the atmospheric concentration of CMIT/MIT, following its use in HD, would be lower than expected assuming that it is removed by ventilation only. In order to evaluate the exposure concentration of CMIT/MIT used as an HD, room-scale chamber studies were conducted under plausible use of three different HD doses at air change rates (ACR) of 0.

View Article and Find Full Text PDF

Background: Use of humidifier disinfectants (HD) at home leads to chemical airborne exposure, causing HD associated lung injury (HDLI) with high mortality. However, the lung function in children diagnosed with HDLI is not well studied. We investigated the effect of HD exposure on lung function, prognosis, and exposure characteristics associated with the lung function phenotype in children.

View Article and Find Full Text PDF

Since around the year 2000, hundreds of people in Korea have developed humidifier disinfectant-associated lung injury (HDLI). We collected all HD exposure-related information from the field investigations into the locations in which the 1199 registered patients had used HD. Among the people who registered, 38% (1st round = 214, 2nd = 73, 3rd = 166) were confirmed as HDLI patients.

View Article and Find Full Text PDF

Background: Children aged ≤6years reportedly account for 52% of victims of humidifier disinfectant-associated lung injuries.

Objectives: To evaluate the association of humidifier disinfectants with lung injury risk among children aged ≤6years.

Methods: Patients with humidifier disinfectant-associated lung injuries (n=214) who were clinically evaluated to have a definite (n=108), probable (n=49), or possible (n=57) association with humidifier disinfectants as well as control patients (n=123) with lung injury deemed unlikely to be associated with humidifier disinfectant use were evaluated to determine factors associated with increased risk of humidifier disinfectant-associated lung injury using unconditional multiple logistic regression analysis.

View Article and Find Full Text PDF
Article Synopsis
  • From 2002 to 2015, significant lung injuries and fatalities linked to humidifier disinfectants (HDs) occurred in Korea, primarily affecting pregnant women and young children.
  • A study examined 530 registered lung disease cases, confirming about 221 were directly associated with HD use, revealing a high incidence of injuries within the first year of use.
  • The most commonly implicated disinfectants were those containing polyhexamethylene guanidine phosphate (PHMG), followed by oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH) ), indicating a strong link between specific HD products and lung injuries.
View Article and Find Full Text PDF

The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled.

View Article and Find Full Text PDF

It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure.

View Article and Find Full Text PDF

Objective: The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM.

Methods: A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014.

View Article and Find Full Text PDF

We analyzed national data on blood lead levels (BLL) and blood cadmium levels (BCL) in residents living near 38 abandoned metal mining areas (n = 5,682, 18-96 years old) in Korea that were collected by the first Health Effect Surveillance for Residents in Abandoned Metal mines (HESRAM) from 2008 to 2011. The geometric mean BCL and BLL were 1.60 μg/L (95 % CI = 1.

View Article and Find Full Text PDF

Background: Municipal workers handling household waste are potentially exposed to a variety of toxic and pathogenic substances, in particular airborne bacteria, gram-negative bacteria (GNB), and fungi. However, relatively little is known about the conditions under which exposure is facilitated.

Methods: This study assessed levels of airborne bacteria, GNB, and fungi, and examined these in relation to the type of waste-handling activity (collection, transfer, transport, and sorting at the waste preprocessing plant), as well as a variety of other environmental and occupational factors.

View Article and Find Full Text PDF

Purpose: This study was performed to investigate polycyclic aromatic hydrocarbons (PAHs) exposure in the area around a cement factory with kilns using waste, including refuse plastic fuel.

Methods: Atmospheric total suspended particulates (TSPs) for each of an exposed area and a non-exposed area were collected. Similarly, urine samples were collected from 330 subjects in the exposed area and 126 subjects in the non-exposed area.

View Article and Find Full Text PDF

Objectives: This study was conducted to assess the size characteristics of particulate matter (PM) generated during waste collection and sorting, and to assess the effect of the type of waste-handling activity on levels of coarse and fine PM.

Methods: A portable aerosol spectrometer calibrated to 1.2 //min was used to monitor PM generated during four types of waste-handling activities.

View Article and Find Full Text PDF

This study was conducted to assess inhalation exposure to dust, endotoxin, and microorganisms (including viable bacteria, Gram-negative bacteria [GNB], and fungi) during waste collection and sorting; to identify factors affecting this exposure; and to estimate the gastrointestinal exposure to microorganisms. A total of 48 or 49 workers involved in collecting and sorting waste from households or the street were studied. Each worker carried two personal samplers in which filters were placed in the breathing zone for estimation of inhalation exposure.

View Article and Find Full Text PDF