BACKGROUND: Indoor air quality (IAQ) is an important determinant of human health. In Japan, IAQ guidelines have been established for 13 chemicals since 1997. Regarding ethylbenzene (EB), a previous guideline value of 3800 µg/m³ was established in 2000. However, the Ministry of Health, Labour, and Welfare decided to revise the value because of the publication of new hazard information after the establishment of the previous guideline value and the establishment of their respective IAQ guidelines by foreign organizations based on the new hazard information. This study conducted a detailed hazard assessment on EB and derived hazard assessment values to provide a toxicologically valid basis for revising the IAQ guideline value. METHODS: As it was defined that the IAQ guidelines would not exert adverse health effects on humans even if they inhaled the chemicals from indoor air over a lifetime, we investigated the general toxicity, developmental and reproductive toxicity, genotoxicity, and carcinogenicity of EB based on reliable hazard information cited in published assessment documents by domestic, foreign, or international risk assessment organizations. All the collected hazard information was examined, and we originally judged the no-observed adverse effect level and the lowest observed adverse effect level of each toxicity study. We then selected the most appropriate key study, an endpoint, and a point of departure and derived the hazard assessment values for each toxicity category. Finally, we selected a representative hazard assessment value for EB from the minimum hazard assessment value among general toxicity, developmental and reproductive toxicity, and carcinogenicity. RESULTS: Among the three toxicity categories, the minimum hazard assessment value was obtained from general toxicity, which was 0.0858 ppm (370 µg/m³) based on the loss of the outer hair cells in the organ of Corti in the cochlea observed in a 13-week repeated-dose inhalation toxicity study using rats. CONCLUSIONS It would be appropriate to adopt 0.0858 ppm (370 µg/m³) as a representative hazard assessment value to provide a basis for revising the IAQ guideline value for EB.
Japan ; Air Pollution, Indoor/adverse effects* ; Risk Assessment ; Humans ; Benzene Derivatives/toxicity* ; Guidelines as Topic ; Animals ; Air Pollutants/toxicity*

Per- and polyfluoroalkyl substances (PFAS) have recently been shown to affect human health at low levels in the blood, according to epidemiological evidence. Consequently, human exposure to these chemicals should be strictly controlled to prevent health risks. This review reports on the potential sources of PFAS using Japan as an example. Tap water has attracted attention as a source of exposure to PFAS. PFAS have also been detected in the air, in household dust, and in consumer products. Furthermore, in the general population, diet is the most common source of exposure, and there is particular concern about human exposure to PFAS accumulated in seafood. Continuous monitoring is important for appropriate management of exposure for both humans and the environment.
Seafood/toxicity* ; Fluorocarbons/toxicity* ; Japan ; Drinking Water/standards* ; Air Pollutants/toxicity* ; Humans ; Dust/analysis* ; Environmental Exposure/standards* ; Food Contamination/analysis* ; Environmental Pollutants/toxicity* ; Water Pollutants, Chemical/toxicity*

Humans ; Diabetes Mellitus, Type 2/epidemiology* ; Air Pollution/adverse effects* ; Air Pollutants/toxicity* ; Risk Assessment ; Particulate Matter ; Environmental Exposure

Ozone/toxicity* ; Air Pollution/analysis* ; Air Pollutants/analysis* ; China/epidemiology* ; Environmental Exposure/analysis* ; Mortality ; Particulate Matter/analysis*

Ambient fine particulate matters (PM_2.5) refer to particulate matters with an aerodynamic diameter less than or equal to 2.5 μm. PM_2.5 enter the body through the target organ-lung, and can induce a variety of adverse health effects (such as cardiovascular diseases, diabetes, respiratory diseases, neurodegenerative diseases and adverse birth outcomes). PM_2.5 are known to have complex compositions (including water-soluble/-insoluble components and biological components), diverse sources and capacity of secondary transformation. Numerous epidemiological and toxicological studies indicated that different components of PM_2.5 may induce adverse health effects through different biological mechanisms. In adddition, co-exposure of different components and their interaction should also be considered. Thus here we have systematically reviewed studies in recent years about the toxicological effects and underlying mechanisms of different components of ambient fine particulate matters, including inflammatory response, oxidative stress, endoplasmic reticulum stress, activation of the NF-κB signaling pathway and so on. The information may give some insights into the prevention and treatment of adverse health effects caused by exposure to different components of PM_2.5.
Air Pollutants/toxicity* ; Cardiovascular Diseases/chemically induced* ; Humans ; Lung ; Oxidative Stress ; Particulate Matter/toxicity*

Objective: To screen the differential methylation sites, genes and pathways of air pollution fine particles (PM(2.5)) on human bronchial epithelial (HBE) cells by methylation chip and bioinformation technology, so as to provide scientific basis for further study of the toxicological mechanism of PM(2.5) on HBE cells. Methods: In August 2020, HBE cells were infected with 10 μg/ml and 50 μg/ml PM(2.5) aqueous solution for 24 h, namely PM(2.5) 10 μg/ml exposure group (low dose group) and PM(2.5) 50 μg/ml exposure group (high dose group) ; uninfected HBE cells were used as control group. The DNA fragments were hybridized with the chip, the chip scanned and read the data, analyzed the data, screened the differential methylation sites, carried out GO analysis and KEGG analysis of the differential methylation sites, and analyzed the interaction relationship of the overall differential methylation sites by functional epigenetic modules (FEMs). Results: Compared with the control group, 127 differential methylation sites were screened in the low-dose group, including 89 genes, including 55 sites with increased methylation level and 72 sites with decreased methylation level. The differential methylation sites were mainly concentrated in the Body region and UTR region. Compared with the control group, 238 differential methylation sites were screened in the high-dose group, including 168 genes, of which 127 sites had increased methylation level and 111 sites had decreased methylation level. The differential heterotopic sites were mainly concentrated in the Body region and UTR region. Through FEMs analysis, 8 genes with the most interaction were screened, of which 6 genes had significant changes in methylation level. MALT1 gene related to apoptosis was found in the heterotopic site of methylation difference in low-dose group; PIK3CA and ARID1A genes related to carcinogenesis were found in the heterotopic sites of methylation difference in high-dose group; TNF genes related to tumor inhibition were found in the results of FEMs analysis. Conclusion: After PM(2.5) exposure to HBE cells, the DNA methylation level is significantly changed, and genes related to apoptosis and carcinogenesis are screened out, suggesting that the carcinogenic mutagenic effect of PM(2.5) may be related to DNA methylation.
Air Pollutants/toxicity* ; Basic Helix-Loop-Helix Transcription Factors/analysis* ; Carcinogenesis ; DNA Methylation ; Humans ; Particulate Matter/toxicity* ; Technology

Objective: Epidemiological studies reveal that exposure to fine particulate matter (aerodynamic diameter ≤ 2.5 μm, PM Methods: EVs were isolated from the serum of healthy subjects, quantified Results: PM Conclusions EVs treatment promotes cell survival and attenuates PM
A549 Cells ; Air Pollutants/toxicity* ; Apoptosis/drug effects* ; Cell Survival/drug effects* ; Extracellular Vesicles ; Humans ; Male ; Middle Aged ; Particulate Matter/toxicity* ; Protective Agents/pharmacology* ; Proto-Oncogene Proteins c-akt/metabolism* ; Serum

Objective To quantitatively evaluate the associations of PM
Air Pollutants/toxicity* ; Air Pollution/adverse effects* ; Child, Preschool ; China ; Dermatitis, Atopic/epidemiology* ; Female ; Humans ; Male ; Outpatients ; Particulate Matter/analysis*

OBJECTIVES: The association between concentrations of sulfur dioxide (SO), nitrogen dioxide (NO), carbon monoxide (CO), ozone (O), and emergency ambulance dispatches (EADs) for asthma was explored in the central Sichuan Basin of southwestern China for the first time. METHODS: EADs for asthma were collected from the Chengdu First-Aid Command Center. Pollutant concentrations were collected from 24 municipal environmental monitoring centers and including SO, NO, CO, daily 8-h mean concentrations of O (O-8 h), and particulate matter less than 2.5 μm in aerodynamic diameter (PM). The climatic data were collected from the Chengdu Municipal Meteorological Bureau. All data were collected from years spanning 2013-2017. A time-stratified case-crossover design was used to analyze the data. RESULTS: After controlling for temperature, relative humidity, and atmospheric pressure, IQR increases in SO (13 μg/m), NO (17 μg/m), and CO (498 μg/m) were associated with 18.8%, 11.5%, and 3.1% increases in EADs for asthma, respectively. The associations were strongest for EADs and SO, NO, and CO levels with 3-, 5-, and 1-day lags, respectively. CONCLUSIONS This study provides additional data to the limited body of literature for potential health risks arising from ambient gaseous pollutants. The results of the study suggest that increased concentrations of SO, NO, and CO were positively associated with emergency ambulance dispatches for asthma in Chengdu, China. Further studies are needed to investigate the effects of individual air pollutants on asthma.
Air Pollutants ; analysis ; toxicity ; Asthma ; chemically induced ; epidemiology ; Carbon Monoxide ; analysis ; toxicity ; China ; epidemiology ; Cities ; Cross-Over Studies ; Emergency Medical Dispatch ; statistics & numerical data ; Environmental Monitoring ; statistics & numerical data ; Humans ; Nitrogen Dioxide ; analysis ; toxicity ; Ozone ; analysis ; toxicity ; Particle Size ; Particulate Matter ; analysis ; toxicity ; Risk ; Sulfur Dioxide ; analysis ; toxicity

With the increasing occurrence of haze during the summer, the physicochemical characteristics and toxicity differences in PM_2.5 in different seasons are of great concern. Hangzhou is located in an area that has a subtropical monsoon climate where the humidity is very high during both the summer and winter. However, there are limited studies on the seasonal differences in PM_2.5 in these weather conditions. In this test, PM_2.5 samples were collected in the winter and summer, the morphology and chemical composition of PM_2.5 were analyzed, the toxicity of PM_2.5 to human bronchial cells BEAS-2B was compared, and the correlation between PM_2.5 toxicity and the chemical composition was discussed. The results showed that during both the winter and summer, the main compounds in the PM_2.5 samples were water-soluble ions, particularly SO₄^2-, NO₃^-, and NH₄⁺, followed by organic components, while heavy metals were present at lower levels. The higher the mass concentration of PM_2.5, the greater its impact on cell viability and ROS levels. However, when the mass concentration of PM_2.5 was similar, the water extraction from the summer samples showed a greater impact on BEAS-2B than that from the winter samples. The cytotoxicity of PM_2.5 was closely associated with heavy metals and organic pollutants but less related to water-soluble ions.
Air Pollutants/toxicity* ; Bronchi/metabolism* ; Carbon/chemistry* ; Environmental Monitoring ; Humans ; Ions ; Metals, Heavy ; Organic Chemicals ; Particle Size ; Particulate Matter/toxicity* ; Seasons ; Temperature ; Water