Formaldehyde Exposure and Epigenetic Effects: A Systematic Review

A review of recent advances in metal-organic frameworks materials for zero-energy passive adsorption of chemical pollutants in indoor environments

Approximately 75-90 % of a person's lifetime is spent inside increasingly airtight buildings, where indoor pollutant levels typically exceed those outdoors. Poor indoor air quality can lead to allergies, respiratory diseases, and even cancer, and can also reduce the longevity of buildings. Passive adsorption materials play a crucial role in reducing indoor pollutants. This review highlights the latest advances in using Metal-organic Frameworks (MOFs) as passive adsorption materials for indoor pollutant capture and outlines the principles for developing high-performance adsorbents. It provides a comparative analysis of the development and performance of MOFs and composite adsorbent materials, highlighting their respective advantages and limitations in indoor pollutant adsorption technology. The article proposes strategies to address these challenges and offers a comprehensive review of current practical adsorption devices. Finally, aiming to advance commercialization of MOFs, the anticipated development of indoor pollutant adsorption technology is discussed in this paper.

Effect of fish oil supplementation on histological changes, apoptosis and oxidative stress of rat placenta against formaldehyde-induced toxicity

Formaldehyde (FA) as a common organic compound has been shown to cause placental dysfunction and fetal defects. The potential benefits of fish oil (FOil) in protecting placental structures are attributed to its antioxidant properties. This study aimed to explore the preventive role of FOil in mitigating the adverse effects of FA in pregnant rats. Thirty pregnant Wistar rats were randomly categorized into five groups of control, sham (Normal saline; Orally and intraperitoneally), FOil (0.5 ml/day; Orally), FA (5 mg/kg/bw; intraperitoneally), FA+FOil. The treatment period was from day 0-20 of pregnancy. On the 20th day of pregnancy, placental morphometric parameters were measured. The histological and histochemical analyses were performed using H&E and PAS staining, respectively. Also, the placenta tissue was analyzed for oxidative stress biomarkers, p-53 protein levels, and the expression of caspase-3 gene. The administration of FA led to a significant decrease in the weight, diameter, and thickness of the placenta, as well as a decrease in the thickness of the decidua layer, junctional and labyrinth zone, and the number of trophoblast giant cells in rat placentas. FA led to a significant increase in placental p-53 protein levels, caspase-3 expression, and oxidative stress biomarkers. Administration of FOil to pregnant rats treated with FA led to a significant decrease in morphometric and histological changes, oxidative stress, and the expression of genes associated with apoptosis. The findings suggest that the administration of FOil to FA-treated pregnant rats can protect placental histopathological changes by enhancing the activity of the antioxidant enzymes.

Multi-sensor monitoring and analysis of indoor pollutant emissions in response to laser cutter operating conditions

This study analyzed pollutant emissions from laser cutters used in modeling in a laboratory, which can have harmful effects on indoor air quality and health. Four conditions were tested: material thickness, laser cutter strength, minimum strength per thickness, and air purifier level. Four pollutants were analyzed: PM2.5, HCHO, VOCs, and CO2. The study found that the emissions of PM2.5, HCHO, and VOCs increased with paperboard thickness, while CO2 emissions were not significant. PM2.5 was more affected by laser cutting strength, while HCHO and VOCs were more affected by paperboard thickness. Additionally, we analyzed the PM2.5 emission rates based on the thickness of the paperboard and the laser cutting strength. Therefore, emission rates based on thickness and laser cutting strength ranged from 7275 to 18,783 μg/min. The air purifier significantly reduced PM2.5 but not HCHO and VOCs. To reduce these gaseous pollutants, combining mechanical ventilation or using an air purifier with a filter that adsorbs HCHO and VOCs is effective. This study highlights the importance of considering laser cutters as a potential source of indoor air pollutants and implementing measures to mitigate their harmful effects.

Health risk assessment from inhalation exposure to indoor formaldehyde: A systematic review and meta-analysis

This systematic review and meta-analysis investigated studies on formaldehyde (FA) inhalation exposure in indoor environments and related carcinogenic (CR) and non-carcinogenic (HQ) risk. Studies were obtained from Scopus, PubMed, Web of Science, Medline, and Embase databases without time limitation until November 21, 2023. Studies not meeting the criteria of Population, Exposure, Comparator, and Outcomes (PECO) were excluded. The 45 articles included belonged to the 5 types of sites: dwelling environments, educational centers, kindergartens, vehicle cabins, and other indoor environments. A meta-analysis determined the average effect size (ES) between indoor FA concentrations, CR, and HQ values in each type of indoor environment. FA concentrations ranged from 0.01 to 1620 μg/m3. The highest FA concentrations were stated in water pipe cafés and the lowest in residential environments. In more than 90% of the studies uncertain (1.00 ×10-6 1.00 ×10-4) due to FA inhalation exposure was reported and non-carcinogenic risk was stated acceptable. The meta-analysis revealed the highest CR values due to inhalation of indoor FA in high-income countries. As 90% of the time is spent indoors, it is crucial to adopt effective strategies to reduce FA concentrations, especially in kindergartens and schools, with regular monitoring of indoor air quality.

Human exposure to formaldehyde and health risk assessment: a 46-year systematic literature review

After confirming that formaldehyde (FA) is carcinogenic, many studies were conducted in different countries to investigate this finding. Therefore, according to the dispersion of related studies, a bibliometric review of the current literature was performed with the aim of better understanding the exposure to FA and the resulting health risk, for the first time, using the Scopus database and the two open-source software packages, Bibliometrix R package. After screening the documents in Excel, the data was analyzed based on three aspects including performance analysis, conceptual structure, and intellectual structure, and the results were presented in tables and diagrams. A total of 468 documents were analyzed over period 1977-2023, in which 1956 authors from 56 countries participated. The number of scientific publications has grown significantly from 1977 (n = 1) to 2022 (n = 19). Zhang Y., from the Yale School of Public Health (USA), was identified as the most impactful author in this field. The Science of the Total Environment journal was identified as the main source of articles related to exposure to formaldehyde by publishing 25 studies. The United States and China were the most active countries with the most international collaboration. The main topics investigated during these 46 years included "formaldehyde" and "health risk assessment", which have taken new directions in recent years with the emergence of the keyword "asthma". The present study provides a comprehensive view of the growth and evolution of studies related to formaldehyde and the resulting health risks, which can provide a better understanding of existing research gaps and new and emerging issues.

Monitoring, exposure and risk assessment of formaldehyde in alcoholic beverages in Korea

Formaldehyde occurs naturally in food and alcoholic beverages. Formaldehyde and alcoholic beverages can cause various health problems, including irritation of the eyes, nose, and throat, respiratory problems, and skin rashes. Alcoholic beverage samples (N = 236) were collected and analyzed for formaldehyde by liquid chromatography-tandem mass spectrometry. The highest average concentrations were detected in fruit wines (1.71 µg/g), followed by wines (1.15 µg/g), cheongju (0.95 µg/g), soju (0.85 µg/g), takju (0.64 µg/g) and beers (0.61 µg/g). We assessed the exposure and risk assessment to formaldehyde from alcoholic beverages based on the monitoring data for the general population and consumers in Korea using various schemes for point estimation. The daily intakes of formaldehyde for the general population and consumers were estimated to be 83 µg and 1202 µg, respectively. The mean hazard indexes (HI) for the general population and consumers in Korea were 0.009 and 0.132, respectively. On the other hand, the mean hazard indexes (HI) for the general population and consumers in Korea were 0.009 and 0.132, respectively. The exposure to formaldehyde in these alcoholic beverages for the Korean population was shown to be of low concern, but it is necessary to monitor the level of formaldehyde in alcoholic beverages and continuously conduct exposure assessment for consumers.

Inhalational exposure to formaldehyde, carcinogenic, and non-carcinogenic risk assessment: A systematic review

Formaldehyde is one of the most widely used substances in a variety of industries, although it was classified as a human carcinogen by the International Agency for Research on Cancer (IARC). The present systematic review was conducted to retrieve studies related to occupational exposure to formaldehyde until November 2, 2022. Aims of the study were to identify workplaces exposed to formaldehyde, to investigate the formaldehyde concentrations in various occupations and to evaluate carcinogenic and non-carcinogenic risks caused by respiratory exposure to this chemical among workers. A systematic search was done in Scopus, PubMed and Web of Science databases to find the studies done in this field. In this review, studies that did not meet the criteria specified by Population, Exposure, Comparator, and Outcomes (PECO) approach were excluded. In addition, the inclusion of studies dealing with the biological monitoring of FA in the body and review studies, conference articles, books, and letters to the editors were avoided. The quality of the selected studies was also evaluated using the Joanna Briggs Institute (JBI) checklist for analytic-cross-sectional studies. Finally, 828 studies were found, and after the investigations, 35 articles were included in this study. The results revealed that the highest formaldehyde concentrations were observed in waterpipe cafes (1,620,000 μg/m³) and anatomy and pathology laboratories (4237.5 μg/m³). Carcinogenic and non-carcinogenic risk indicated the potential health effects for employees due to respiratory exposure as acceptable levels of CR = 1.00 × 10^-4 and HQ = 1, respectively were reported to be exceeded in more than 71% and 28.57% of the investigated studies. Therefore, according to the confirmation of formaldehyde's adverse health effects, it is necessary to adopt targeted strategies to reduce or eliminate exposure to this compound from the occupational usage.

The exposure to formaldehyde in industries and health care centers: A systematic review and probabilistic health risk assessment

Formaldehyde is classified as a definitive human carcinogen by the International Agency for Research on Cancer (IARC). The workers in several industries such as foundry, melamine, resin, and health care centers (pathology and anatomy laboratories and operating rooms) are exposed to airborne formaldehyde. In this systematic review, studies conducted from 2000 to 2020 on occupational exposure to airborne formaldehyde in Iran were collected and analyzed. The carcinogenic and non-carcinogenic risk assessments of exposure to airborne formaldehyde were estimated using the recommended United State Environmental Protection Agency (USEPA) method by Monte-Carlo simulation. Results demonstrated that in both health care centers and industrial settings, mean concentrations of airborne formaldehyde were higher than that 8- hour time-weighted average threshold limit value (TWA-TLV) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). Also, results showed that cancer and non-cancer risks due to exposure to airborne formaldehyde (Neurological, dermal, respiratory effects and so on) were considerable in both industrial settings and health care settings. The results of this study could be used by health policy makers to eliminate or reduce exposure to airborne formaldehyde in workplaces.

Effect of formaldehyde exposure on bacterial communities in simulating indoor environments

Indoor formaldehyde (CH₂O) exceeding the recommended level is a severe threat to human health. Few studies have investigated its effect on indoor surface bacterial communities, affecting habitants' health. This study used 20-L glass containers to mimic the indoor environment with bacterial inputs from human oral respiration. The behavior of bacterial communities responding to CH₂O varied among the different CH₂O levels. The bacterial community structure significantly changed over time in the 0.054 mg·m^-3 CH₂O group, which varied from the 0.1 mg·m^-3 and 0.25 mg·m^-3 CH₂O groups. The Chao1 and Shannon index significantly increased in the 0.054 mg·m^-3 CH₂O group at 6 week, while they remained unchanged in the 0.25 mg·m^-3 CH₂O group. At 12 week, the Chao1 significantly increased in the 0.25 mg·m^-3 CH₂O group, while it remained unchanged in the 0.054 mg·m^-3 CH₂O group. Only a few Operational Taxonomic Units (OTUs) significantly correlated with the CH₂O concentration. CH₂O-induced OTUs mainly belong to the Proteobacteria and Firmicutes. Furthermore, bacterial communities formed at 6 or 12 weeks differed significantly among different CH₂O levels. Functional analysis of bacterial communities showed that inferred genes related to chemical degradation and diseases were the highest in the 0.25 mg·m^-3 CH₂O group at 12 weeks. The development of nematodes fed with bacteria collected at 12 weeks was applied to evaluate the bacterial community's hazards. This showed significantly impaired growth in the 0.1 mg·m^-3 and 0.25 mg·m^-3 CH₂O groups. These findings confirmed that CH₂O concentration and exposure time could affect the indoor bacterial community and formed bacterial communities with a possibly more significant hazard to human health after long-term exposure to high CH₂O levels.