BACKGROUND: We previously demonstrated that continuous exposure to nitrous acid gas (HONO) for 4 weeks, at a concentration of 3.6 parts per million (ppm), induced pulmonary emphysema-like alterations in guinea pigs. In addition, we found that HONO affected asthma symptoms, based on the measurement of respiratory function in rats exposed to 5.8 ppm HONO. This study aimed to investigate the dose-response effects of HONO exposure on the histopathological alterations in the respiratory tract of guinea pigs to determine the lowest observed adverse effect level (LOAEL) of HONO. METHODS: We continuously exposed male Hartley guinea pigs (n = 5) to four different concentrations of HONO (0.0, 0.1, 0.4, and 1.7 ppm) for 4 weeks (24 h/day). We performed histopathological analysis by observing lung tissue samples. We examined samples from three guinea pigs in each group under a light microscope and measured the alveolar mean linear intercept (Lm) and the thickness of the bronchial smooth muscle layer. We further examined samples from two guinea pigs in each group under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). RESULTS: We observed the following dose-dependent changes: pulmonary emphysema-like alterations in the centriacinar regions of alveolar ducts, significant increase in Lm in the 1.7 ppm HONO-exposure group, tendency for hyperplasia and pseudostratification of bronchial epithelial cells, and extension of the bronchial epithelial cells and smooth muscle cells in the alveolar duct regions. CONCLUSIONS These histopathological findings suggest that the LOAEL of HONO is < 0.1 ppm.
Alveolar Epithelial Cells ; drug effects ; Animals ; Bronchi ; drug effects ; Dose-Response Relationship, Drug ; Emphysema ; chemically induced ; Epithelial Cells ; drug effects ; Guinea Pigs ; Hyperplasia ; chemically induced ; Inhalation Exposure ; adverse effects ; Lung ; drug effects ; pathology ; ultrastructure ; Male ; Microscopy, Electron, Scanning ; Microscopy, Electron, Transmission ; Myocytes, Smooth Muscle ; drug effects ; Nitrous Acid ; toxicity

PURPOSE: Occupational asthma may be induced by high- or low-molecular weight allergens (HMWA or LMWA, respectively). The study was conducted to compare the pattern of bronchial response in 200 HMWA-induced asthmatics (n = 130) and LMWA-induced asthmatics (n = 70). METHODS: The study participants underwent a single-blind, placebo-controlled specific inhalation challenge (SIC) with workplace allergens, accompanied by evaluation of non-specific bronchial hyperresponsiveness (NSBHR) with methacholine before and after the SIC. RESULTS: A single early bronchial response more frequently occurred in HMWA-induced asthmatics than in LMWA-induced asthmatics (86.2% vs. 20%). An isolated late bronchial response or atypical patterns were more frequently observed in LMWA-induced asthmatics than in LMWA-induced asthmatics (45.7% vs. 3.8% or 34.3% vs. 10%, respectively). Baseline NSBHR before SIC was more often detected in LMWA-induced asthmatics than in HMWA-induced asthmatics (81.4% vs. 54.6%), and the median value of the provocation concentration of methacholine was relevantly lower in these patients before and after SIC. A significant 3-fold increase in NSBHR after SIC was observed more often in LMWA-induced asthmatics than in HMWA-induced asthmatics (82.8% vs. 66.1%). In addition, compared to LMWA-induced asthmatics, HMWA-induced asthmatics were older, were more frequently active smokers, showed lower level of NSBHR, and more frequently continued their work in harmful occupational exposure. CONCLUSIONS: The results of this study suggest that HMWA-induced asthmatics may have milder clinical courses and that there is a possibility of job continuation despite asthma exacerbation requiring medical surveillance.
Allergens ; Asthma ; Asthma, Occupational ; Bronchial Hyperreactivity ; Humans ; Immunoglobulin E ; Inhalation ; Methacholine Chloride ; Molecular Weight ; Occupational Exposure ; Prognosis

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.
Air Pollution, Indoor ; Clothing ; Deodorants ; Inhalation Exposure ; Inhalation ; Korea ; Polyurethanes ; Risk Assessment ; Risk Factors ; Seoul

Radon is a naturally occurring radioactive material classified as a carcinogen by the World Health Organization, and is known to be the factor with the second-greatest impact on lung cancer after smoking. An association between radon and lung cancer has consistently been reported in epidemiological studies on mine workers and residents of homes with indoor radon exposure. However, associations between radon and other diseases, such as leukemia and thyroid cancer, have yet to be confirmed due to a lack of consistent research findings and biological relevance. Such associations are unlikely because there is a very low likelihood that organs other than the lungs are exposed to radon upon inhalation due to the short half-life of radon and its progeny and the low permeability of alpha rays. In spring 2018, the radon bed mattress incident occurred, leading to a spike of concern and interest among the public regarding the health effects of radiation exposure. This paper presents a description of radon exposure and its health effects based on the current literature and provides practical information based on health consultations experienced following the 2018 radon mattress incident.
Alpha Particles ; Epidemiologic Studies ; Half-Life ; Inhalation ; Leukemia ; Lung ; Lung Neoplasms ; Miners ; Permeability ; Radiation Exposure ; Radon ; Referral and Consultation ; Smoke ; Smoking ; Thyroid Neoplasms ; World Health Organization

The inhalation of naphthalene used as deodorant balls in public toilets could be an important cancer risk factor. The atmospheric concentration of naphthalene in public toilets (C(in)) was estimated both by a polyurethane foam passive air sampler (PUF-PAS) deployed in nine public toilets in Seoul, Korea and by a steady-state indoor air quality model, including emission estimation using Monte-Carlo simulation. Based on the estimated C(in), cancer risk was also assessed for cleaning workers and the general population. The steady-state C(in) estimated using the estimated emission rate, which assumed that air exchange was the only process by which naphthalene was removed, was much greater than the C(in) value measured using PUF-PAS in nine public toilets, implying the importance of other removal processes, such as sorption to walls and the garments of visitors, as well as decreased emission rate owing to wetting of the naphthalene ball surface. The 95 percentile values of cancer risk for workers based on the estimation by PUF-PAS was 1.6×10⁻⁶, whereas those for the general public were lower than 1×10⁻⁶. The results suggested that naphthalene deodorant balls in public toilets may be an important cancer risk factor especially for the cleaning workers.
Air Pollution, Indoor ; Clothing ; Deodorants ; Inhalation Exposure ; Inhalation ; Korea ; Polyurethanes ; Risk Assessment ; Risk Factors ; Seoul

BACKGROUND: Metalworking fluids (MWFs) are mixtures with inhalation exposures as mists, dusts, and vapors, and dermal exposure in the dispersed and bulk liquid phase. A quantitative risk assessment was performed for exposure to MWF and respiratory disease.METHODS: Risks associated with MWF were derived from published studies and NIOSH Health Hazard Evaluations, and lifetime risks were calculated. The outcomes analyzed included adult onset asthma, hypersensitivity pneumonitis, pulmonary function impairment, and reported symptoms. Incidence rates were compiled or estimated, and annual proportional loss of respiratory capacity was derived from cross-sectional assessments.RESULTS: A strong healthy worker survivor effect was present. New-onset asthma and hypersensitivity pneumonitis, at 0.1 mg/m3 MWF under continuous outbreak conditions, had a lifetime risk of 45%; if the associated microbiological conditions occur with only 5% prevalence, then the lifetime risk would be about 3%. At 0.1 mg/m3, the estimate of excess lifetime risk of attributable pulmonary impairment was 0.25%, which may have been underestimated by a factor of 5 or more by a strong healthy worker survivor effect. The symptom prevalence associated with respiratory impairment at 0.1 mg/m3 MWF was estimated to be 5% (published studies) and 21% (Health Hazard Evaluations).CONCLUSION: Significant risks of impairment and chronic disease occurred at 0.1 mg/m3 for MWFs in use mostly before 2000. Evolving MWFs contain new ingredients with uncharacterized long-term hazards.
Adult ; Alveolitis, Extrinsic Allergic ; Asthma ; Asthma, Occupational ; Chronic Disease ; Dust ; Humans ; Incidence ; Inhalation Exposure ; National Institute for Occupational Safety and Health (U.S.) ; Prevalence ; Risk Assessment ; Survivors

Radon is a naturally occurring radioactive material that is formed as the decay product of uranium and thorium, and is estimated to contribute to approximately half of the average annual natural background radiation. When inhaled, it damages the lungs during radioactive decay and affects the human body. Through many epidemiological studies regarding occupational exposure among miners and residential exposure among the general population, radon has been scientifically proven to cause lung cancer, and radon exposure is the second most common cause of lung cancer after cigarette smoking. However, it is unclear whether radon exposure causes diseases other than lung cancer. Media reports have often dealt with radon exposure in relation to health problems, although public attention has been limited to a one-off period. However, recently in Korea, social interest and concern about radon exposure and its health effects have increased greatly due to mass media reports of high concentrations of radon being released from various close-to-life products, such as mattresses and beauty masks. Accordingly, this review article is intended to provide comprehensive scientific information regarding the health effects of radon exposure.
Background Radiation ; Beauty ; Beds ; Epidemiologic Studies ; Human Body ; Inhalation Exposure ; Korea ; Lung ; Lung Neoplasms ; Masks ; Mass Media ; Miners ; Occupational Exposure ; Radon ; Smoking ; Thorium ; Uranium

BACKGROUND: Although lead neurotoxicity is a known phenomenon, it can often be missed at a primary or secondary care level especially if detailed environmental exposure history is missed. METHODS: This is an outbreak investigation where we observed 15 pediatric cases with neurologic signs and symptoms clustered in a slum area known for an unorganized artificial jewelry industry. Their clinical, biochemical, and epidemiological features were compared with 14 other children from the same region reporting with non-neurological symptoms who were considered as unmatched controls. RESULTS: Cases with neurological manifestations had a higher in-house lead smelting activity [OR 7.2 (95% CI 1.4-38.3)] as compared to controls. Toddlers below 3 years of age were more vulnerable to the effects of lead. CONCLUSION This study emphasizes that many focal sources of lead poisoning still remain especially in the unorganized sector. In cases presenting with unexplained neurotoxicity, specific occupational and environmental inquiry for chemical poisoning, with special consideration for lead, should be actively pursued.
Adolescent ; Air Pollution, Indoor ; adverse effects ; Case-Control Studies ; Child ; Child, Preschool ; Disease Outbreaks ; Female ; Humans ; India ; epidemiology ; Infant ; Inhalation Exposure ; adverse effects ; Jewelry ; poisoning ; Lead ; blood ; standards ; Lead Poisoning ; epidemiology ; pathology ; physiopathology ; Male ; Metallurgy ; Neurotoxicity Syndromes ; epidemiology ; pathology ; physiopathology ; Poverty Areas ; Risk Factors

BACKGROUND: This paper describes a simple-to-use and reliable screening tool called Critical Task Exposure Screening (CTES), developed by a chemical company. The tool assesses if the exposure to a chemical for a task is likely to be within acceptable levels. METHODS: CTES is a Microsoft Excel tool, where the inhalation risk score is calculated by relating the exposure estimate to the corresponding occupational exposure limit (OEL) or occupational exposure band (OEB). The inhalation exposure is estimated for tasks by preassigned ART1.5 activity classes and modifying factors. RESULTS: CTES requires few inputs. The toxicological data, including OELs, OEBs, and vapor pressure are read from a database. Once the substance is selected, the user specifies its concentration and then chooses the task description and its duration. CTES has three outputs that may trigger follow-up: (1) inhalation risk score; (2) identification of the skin hazard with the skin warnings for local and systemic adverse effects; and (3) status for carcinogenic, mutagenic, or reprotoxic effects. CONCLUSION: The tool provides an effective way to rapidly screen low-concern tasks, and quickly identifies certain tasks involving substances that will need further review with, nevertheless, the appropriate conservatism. This tool shows that the higher-tier ART1.5 inhalation exposure assessment model can be included effectively in a screening tool. After 2 years of worldwide extensive use within the company, CTES is well perceived by the users, including the shop floor management, and it fulfills its target of screening tool.
Follow-Up Studies ; Inhalation ; Inhalation Exposure ; Mass Screening* ; Occupational Exposure ; Politics ; Risk Assessment* ; Risk Management ; Skin ; Vapor Pressure

The safety of occupational exposure to inhaled anesthetics remains a concern among the medical staff in hospitals. Few reports are seen about the impact of inhaled anesthetics on the reproductive system, particularly that of males. Several clinical and basic studies on isoflurane and others suggest that inhaled anesthetics affect the reproductive system of rodents by decreasing the sperm count, inducing sperm morphological abnormality, reducing sperm motility, and changing the levels of reproductive hormones, the underlying mechanisms of which are mainly associated with the alteration of the hypothalamic-pituitary-gonadal axis and DNA damage and apoptosis of reproductive cells. This article reviews the main impacts of inhaled anesthetics on the male reproductive system and the possible mechanisms.
Anesthetics, Inhalation ; pharmacology ; Apoptosis ; DNA Damage ; Genitalia, Male ; drug effects ; Humans ; Isoflurane ; pharmacology ; Male ; Occupational Exposure ; Sperm Count ; Sperm Motility ; drug effects ; Spermatozoa ; drug effects