Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment

What are the DNA lesions underlying formaldehyde toxicity?

Formaldehyde is a highly reactive organic compound. Humans can be exposed to exogenous sources of formaldehyde, but formaldehyde is also produced endogenously as a byproduct of cellular metabolism. Because formaldehyde can react with DNA, it is considered a major endogenous source of DNA damage. However, the nature of the lesions underlying formaldehyde toxicity in cells remains vastly unknown. Here, we review the current knowledge of the different types of nucleic acid lesions that are induced by formaldehyde and describe the repair pathways known to counteract formaldehyde toxicity. Taking this knowledge together, we discuss and speculate on the predominant lesions generated by formaldehyde, which underly its natural toxicity.

Low-temperature thermocatalytic removal of formaldehyde in air using copper manganite spinels

The removal of formaldehyde (FA) is vital for indoor air quality management in light of its carcinogenic propensity and adverse environmental impact. A series of copper manganite spinel structures (e.g., CuMn2O4) are prepared using the sol-gel combustion method and treated with reduction or oxidation pretreatment methods at 300°C condition. Accordingly, CuMn2O4-O ("O" suffix for oxidation pre-treatment in air) is identified as the best performer to achieve 100% conversion (XFA) of FA (50 ppm) at 90°C; its performance, if assessed in terms of reaction kinetic rate (r) at XFA =10%, is 5.02E-03 mmol g-1 h-1. The FA removal performance increases systematically with decreases in flow rate, FA concentration, and relative humidity (RH) or with increases in bed mass. The reaction pathways and intermediates of FA catalytic oxidation on CuMn2O4-A are studied with density functional theory simulations, temperature-programmed characterization experiments, and in-situ diffuse reflectance infrared Fourier transform spectroscopy. The synergistic combination of large quantities of adsorbed oxygen (OA) species and oxidized metal species (e.g., Cu2+) contribute to the enhanced catalytic performance of CuMn2O4-O to oxidize FA into CO2 with the reaction intermediates of H2CO2 (DOM), HCOO-, and CO. The present study is expected to provide valuable insights into the thermocatalytic oxidation of FA over spinel CuMn2O4 materials and their catalytic performances in relation to the key process variables.

Ambient air formaldehyde levels during skin biopsies

Formaldehyde is a carcinogenic agent regularly used in dermatology clinics to prepare skin biopsy specimens for histopathology. The objective of this study was to measure formaldehyde concentrations using an air quality meter in an examination room during exposure to open formaldehyde-containing skin biopsy specimen containers. Formaldehyde concentration in the examination room remained low throughout the 60 min of exposure to both one and five opened formaldehyde-containing specimen containers, at levels below the short-term exposure limits imposed by the World Health Organization, Occupational Safety and Health Administration and National Institute for Occupational Safety and Health.

Growth of Ag/g-C3N4 nanocomposites on nickel foam to enhance photocatalytic degradation of formaldehyde under visible light

Formaldehyde is a pollutant that significantly affects the indoor air quality. However, conventional remediation approaches can be challenging to deal with low-concentration formaldehyde in an indoor environment. In this study, Photocatalysts of Ag/graphitic carbon nitride (g-C3N4)/Ni with 3D reticulated coral structure were prepared by thermal polymerization and liquid phase photo-deposition, using nickel foam (NF) as the carrier. Experiments demonstrated that when the Ag concentration was 3%, and the relative humidity was 60%, the Ni/Ag/g-C3N4 showed the maximum degradation rate of formaldehyde at 90.19% under visible light irradiation, and the formaldehyde concentration after degradation was lower than the Hygienic standard stated by the Chinese Government. The porous structure of Ni/Ag/g-C3N4 and the formation of Schottky junctions promoted the Adsorption efficiency and degradation of formaldehyde, while the nickel foam carrier effectively promoted the desorption of degradation products. Meanwhile, the degradation rate was only reduced by 3.4% after 16 recycles, the three-dimensional porous structure extended the lifetime of the photocatalyst. This study provides a new strategy for the degradation of indoor formaldehyde at low concentrations.

Imparting Chemiresistor with Humidity-Independent Sensitivity toward Trace-Level Formaldehyde via Substitutional Doping Platinum Single Atom

The modification of metal oxides with noble metals is one of the most effective means of improving gas-sensing performance of chemiresistors, but it is often accompanied by unintended side effects such as sensor resistance increases up to unmeasurable levels. Herein, a carbonization-oxidation method is demonstrated using ultrasonic spray pyrolysis technique to realize platinum (Pt) single atom (SA) substitutional doping into SnO2 (named PtSA-SnO2 ). The substitutional doping strategy can obviously enhance gas-sensing properties, and meanwhile decrease sensor resistance by two orders of magnitude (decreased from ≈850 to ≈2 MΩ), which are attributed to the tuning of band gap and fermi-level position, efficient single atom catalysis, and the raising of adsorption capability of formaldehyde, as validated by the state-of-the-art characterizations, such as spherical aberration-corrected scanning transmission electron microscopy (Cs -corrected STEM), in situ diffuse reflectance infrared Fourier transformed spectra (in situ DRIFT), CO temperature-programmed reduction (CO-TPR), and theoretical calculations. As a proof of concept, the developed PtSA-SnO2 sensor shows humidity-independent (30-70% relative humidity) gas-sensing performance in the selective detection of formaldehyde with high response, distinguishable selectivity (8< Sformaldehyde /Sinterferant <14), and ultra-low detection limit (10 ppb). This work presents a generalized and facile method to design high-performance metal oxides for chemical sensing of volatile organic compounds (VOCs).

Constructing α-MnO2/Mn2O3 heterojunction for formaldehyde oxidation

Constructing heterojunctions with oxygen defect-rich structures and abundant phase interfaces poses an appealing yet challenging task in the development of non-precious metal oxide catalysts for formaldehyde (HCHO) oxidation. Herein, we present a simple and efficient method for fabricating highly active manganese oxide heterojunction catalysts for HCHO oxidation. This method involves the hydrothermal synthesis of a nanostructured α-MnO2/γ-MnOOH composite, followed by mechanical milling-induce phase transformation of γ-MnOOH to Mn2O3. Importantly, mechanical milling not only creates the heterojunction but also imparts oxygen defect-rich structures and an abundant phase interface to the catalyst. The resulting α-MnO2/Mn2O3 heterojunction exhibits outstanding performance in HCHO oxidation, comparable to the best non-precious metal oxide catalysts reported thus far. It achieves a 100% conversion of 100 ppm HCHO under a gas hourly space velocity of 120 L gcat-1 h-1 at 80 °C, corresponding to a mass-specific reaction rate of 8.92 μmol g-1 min-1 and an area-specific reaction rate of 0.18 μmol m-2 min-1. Based on the control experiments using in situ diffuse reflectance infrared Fourier transform spectroscopy combined with online gas chromatography, we gained insights into the mechanism of HCHO oxidation over the α-MnO2/Mn2O3 catalyst and the functional roles played by its component phases.

Assessment of atmospheric levels of carbonyls in an urban environment of Argentina

It is well-documented that carbonyl compounds have adverse effects on human health. On the other hand, these oxygenated volatile organic compounds (OVOCs) are precursors of secondary pollutants such as tropospheric ozone or peroxy acetyl nitrate (PAN). In particular, formaldehyde, the simplest carbonyl, is the most abundant carbonyl in the air generated from the degradation of most volatile organic compounds (VOCs). This work presents for the first time the characterization and determination of levels of carbonyl compounds by passive monitoring performed from April-December 2021 in the city of Córdoba, Argentina, the second most populated Mediterranean city located in the center of the country. Annual concentrations, considering the 11 carbonyls measured, were in the range of 0.13-8.75 μgm-3. Formaldehyde and acetaldehyde were the carbonyls detected in the highest annual average concentrations of 4.44 ± 1.75 μgm-3 and 3.85 ± 1.44 μgm-3, respectively. These carbonyls represent a contribution of around 40-57% on total carbonyls measured. Statistical analysis to determine significant differences and Pearson correlations with the meteorological parameters were performed. Spring and summer were found to be the seasons with the highest carbonyl concentration linked to forest fire episodes, especially in springtime. The values for the C1/C2 and C2/C3 ratios showed that sources of carbonyl formation are anthropogenic. In addition, the prop-Equiv concentration was determined, where formaldehyde and acetaldehyde were the main producers of tropospheric ozone. The ozone formation potential (OFP) showed that spring and summer are the seasons where carbonyls contribute to the formation of tropospheric ozone.This study represents a first approach of the carbonyl concentration in the city and of the influence of meteorological parameters on the behavior of carbonyls.

China's air quality improvement strategy may already be having a positive effect: evidence based on health risk assessment

Aiming to investigate the health risk impact of PM2.5 pollution on a heavily populated province of China. The exposure response function was used to assess the health risk of PM2.5 pollution. Results shows that the total number of premature deaths and diseases related to PM2.5 pollution in Shandong might reach 159.8 thousand people based on the new WHO (2021) standards. The health effects of PM2.5 pollution were more severe in men than in women. Five of the 16 cities in Shandong had higher health risks caused by PM2.5 pollution, including LinYi, HeZe, JiNing, JiNan, and WeiFang. PM2.5 pollution resulted in nearly 7.4 billions dollars in healthy economic cost, which accounted for 0.57% of GDP in Shandong in 2021. HeZe, LiaoCheng, ZaoZhuang, and LinYi were the cities where the health economic loss was more than 1% of the local GDP, accounted for 1.30, 1.26, 1.08, and 1.04%. Although the more rigorous assessment criteria, the baseline concentration was lowered by 30 μg/m3 compared to our previous study, there was no significant increase in health risks and economic losses. China's air quality improvement strategy may already be having a positive effect.

A New Perspective on SPME and SPME Arrow: Formaldehyde Determination by On-Sample Derivatization Coupled with Multiple and Cooling-Assisted Extractions

Formaldehyde (FA) is a toxic compound and a human carcinogen. Regulating FA-releasing substances in commercial goods is a growing and interesting topic: worldwide production sectors, like food industries, textiles, wood manufacture, and cosmetics, are involved. Thus, there is a need for sensitive, economical, and specific FA monitoring tools. Solid-phase microextraction (SPME), with O-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBHA) on-sample derivatization and gas chromatography, is proposed for FA monitoring of real-life samples. This study reports the use of polydimethylsiloxane (PDMS) as a sorbent phase combined with innovative commercial methods, such as multiple SPME (MSPME) and cooling-assisted SPME, for FA determination. Critical steps, such as extraction and sampling, were evaluated in method development. The derivatization was performed at 60 °C for 30 min, followed by 15 min sampling at 10 °C, in three cycles (SPME Arrow) or six cycles (SPME). The sensitivity was satisfactory for the method's purposes (LOD-LOQ at 11-36 ng L^-1, and 8-26 ng L^-1, for SPME and SPME Arrow, respectively). The method's linearity ranges from the lower LOQ at trace level (ng L^-1) to the upper LOQ at 40 mg L^-1. The precision range was 5.7-10.2% and 4.8-9.6% and the accuracy was 97.4% and 96.3% for SPME and SPME Arrow, respectively. The cooling MSPME set-up applied to real commercial goods provided results of quality comparable to previously published data.

A novel fluorescent probe for the detection of formaldehyde in real food samples, animal serum samples and gaseous formaldehyde

Formaldehyde (FA) is widely used as an adhesion promoter and dyeing aid in industrial production. Ingestion of a certain amount of formaldehyde may cause corrosive burns in the mouth, throat, and digestive tract. Therefore, it is very necessary to use simple and effective detection methods to ensure human health and food safety. Herein, a novel fluorescent probe NFD based on naphthalimide for the detection of formaldehyde in food was designed and synthesized. The probe had a remarkable fluorescence response to formaldehyde at 554 nm. And it exhibited fascinating advantages of good selectivity, high sensitivity, and low detection limit. In addition, the solid sensor prepared by loading the probe on the filter paper was successfully realized the visual detection of liquid and gaseous formaldehyde. More importantly, the probe possessed excellent stability in the detection of formaldehyde in real food samples and animal serum samples.

Design of a microfluidic lung chip and its application in assessing the toxicity of formaldehyde

In this work, a microfluidic lung chip with membrane supporting cell growth that can produce multiple concentration gradients of gas and liquid is introduced. The chip is composed of a gas gradient layer in the upper part, a porous membrane supporting cell growth in the middle and a liquid gradient layer in the lower part. The gas-liquid interface environment of the cells on the membrane can expose the cells to the gas in the upper layer and the liquid in the lower layer at the same time. Then, the chip is applied to the toxicity testing of formaldehyde in A549 cells. The results showed that at 6 × 10-5 mol/L formaldehyde, the survival rate of the cells in four channels were 90, 87, 81, and 71%, which shows a dose-response trend under the influence of different concentrations of formaldehyde. ROS staining results also showed that formaldehyde exposure at 6 × 10-5 mol/L lead to the increase of ROS level in the cells. These results suggest that the chip based on cell growth on membrane could be used for toxicological evaluation of environmental polluting gases.

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.

Relationship between formaldehyde exposure, respiratory irritant effects and cancers: a review of reviews

OBJECTIVES

Formaldehyde is an organic compound used in the production of resins, paper, wood plywood, solvents and cleaning products. Formaldehyde is also present when tobacco is smoked. Formaldehyde has been defined as an irritant and is classified as a human carcinogen by the International Agency for Research on Cancer. The purpose of this study was to demonstrate the following two distinct correlations: (1) the association between formaldehyde exposure and development of irritant diseases affecting the respiratory tract, mainly asthma; and (2) the association between formaldehyde exposure and development of neoplastic diseases.

STUDY DESIGN

This was an umbrella review.

METHODS

A search was conducted in the three main electronic databases of scientific literature: PubMed, Scopus and Web of Science. The search included systematic reviews and meta-analyses published in the previous 10 years. Initially, titles and abstracts of retrieved articles were evaluated, then full-text assessments of selected articles took place. Data extraction and quality assessment were performed according to Assessing the Methodological Quality of Systematic Reviews (AMSTAR) score.

RESULTS

A total of 630 articles were initially collected. Nine articles concerning the association between formaldehyde exposure and asthma were included in the present review, and the majority of these reported good association. In addition, 27 articles investigating the association between formaldehyde exposure and neoplastic diseases were included in the review. These studies showed that nasopharyngeal cancer and leukaemia were the most represented neoplastic diseases; however, only a weak association was reported between formaldehyde exposure and cancer.

CONCLUSIONS

Although the studies included in this review did not show a strong association between exposure to formaldehyde and irritant or neoplastic diseases, the World Health Organisation recommends that levels of formaldehyde do not exceed the threshold value of 0.1 mg/m³ (0.08 ppm) for a period of 30 min. It is recommended that preventive measures, such as ventilation in workplaces with high exposure to formaldehyde and environmental monitoring of formaldehyde concentrations, are implemented.

Electrochemical and Optical Sensors for the Detection of Chemical Carcinogens Causing Leukemia

The incidence and mortality due to neoplastic diseases have shown an increasing tendency over the years. Based on GLOBOCAN 2020 published by the International Agency for Research on Cancer (IARC), leukemias are the thirteenth most commonly diagnosed cancer in the world, with 78.6% of leukemia cases diagnosed in countries with a very high or high Human Development Index (HDI). Carcinogenesis is a complex process initiated by a mutation in DNA that may be caused by chemical carcinogens present in polluted environments and human diet. The IARC has identified 122 human carcinogens, e.g., benzene, formaldehyde, pentachlorophenol, and 93 probable human carcinogens, e.g., styrene, diazinone. The aim of the following review is to present the chemical carcinogens involved or likely to be involved in the pathogenesis of leukemia and to summarize the latest reports on the possibility of detecting these compounds in the environment or food with the use of electrochemical sensors.

The Minderoo-Monaco Commission on Plastics and Human Health

Background

Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted.

Goals

The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives.

Report Structure

This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations.

Plastics

Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked.

Plastic Life Cycle

The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic.

Environmental Findings

Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being.

Human Health Findings

Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life.

Economic Findings

Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation.

Social Justice Findings

The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs.

Conclusions

It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals.

Recommendations

To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs.

Summary

This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.

Ozone catalytic oxidation of low-concentration formaldehyde over ternary Mn-Ce-Ni oxide catalysts modified with FeOx

Manganese oxide-based catalysts have attracted extensive attention due to their relatively low cost and remarkable performance for removing VOCs. In this research, we used the Pechini method to synthesize manganese-cerium-nickel ternary oxide catalysts (MCN) and evaluated the effectiveness of catalytic destruction of formaldehyde (HCHO) and ozone at room temperature. FeO_x prepared by the impregnation method was applied to modify the catalyst. After FeO_x treatment, the catalyst represented the best performance on both HCHO destruction and ozone decomposition under dry conditions and exhibited excellent water vapor resistance. The as-prepared catalysts were next characterized via H₂-temperature programmed reduction (H₂-TPR), temperature programmed desorption of O₂ (O₂-TPD), and X-ray photoelectron spectroscopy (XPS), and the results demonstrated that addition of FeO_x increased Mn³⁺ and Ce³⁺ concentrations, oxygen vacancies and surface lattice oxygen species, facilitated adsorption, and redox properties. Based on the results of in situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS), possible mechanisms of ozone catalytic oxidation of HCHO were proposed. Overall, the ternary mixed-oxide catalyst developed in this study holds great promise for HCHO and ozone decomposition in the indoor environment.

Formaldehyde and Acetaldehyde Exposure in "Non-Traditional" Occupational Sectors: Bakeries and Pastry Producers

INTRODUCTION

Formaldehyde, a colorless and highly irritating substance, causes cancer of the nasopharynx and leukemia. Furthermore, it is one of the environmental mutagens to which humans are most abundantly exposed. Acetaldehyde was recently classified as carcinogen class 1B and mutagen class 2 in Annex VI EC regulation. Occupational exposure to the two aldehydes occurs in a wide variety of occupations and industries. The aim of this study is to deepen exposure to the two aldehydes in the non-traditional productive sectors of bakeries and pastry producers.

METHODS

The evaluation of exposure to formaldehyde and acetaldehyde was conducted in Italy in 2019, in specific tasks and positions of 11 bakeries and pastry producers (115 measures, of which 57.4% were in fixed positions and the rest were personal air sampling). The measurements were performed using Radiello© radial diffusion samplers. A logarithmic transformation of the data was performed, and the correlation between the two substances was calculated. Moreover, linear models considering the log-formaldehyde as the outcome and adjusting for log-acetaldehyde values were used.

RESULTS

The study identified high levels of acetaldehyde and formaldehyde exposure in the monitored workplaces. Higher mean values were observed in the leavening phase (8.39 µg/m³ and 3.39 µg/m³ for log-transformed data acetaldehyde and formaldehyde, respectively). The adjusted univariate analyses show statistically significant factors for formaldehyde as the presence of yeast, the presence of type 1 flour, the use of barley, the use of fats, the type of production, the use of spelt, and the presence of type 0 flour.

CONCLUSIONS

The measurements confirmed the release of formaldehyde and acetaldehyde in bakeries and pastry industries, especially in some phases of the work process, such as leavening.

Injectable Nanomedicine-Hydrogel for NIR Light Photothermal-Chemo Combination Therapy of Tumor

Traditional hydrogels have drawbacks such as surgical implantation, large wound surfaces, and uncontrollable drug release during tumor treatment. In this paper, targeted nanomedicine has been combined with injectable hydrogel for photothermal-chemotherapy combination therapy. First, targeted nanomedicine (ICG-MTX) was fabricated by combining near-infrared (NIR) photothermal reagents (ICG) and chemotherapy drugs (MTX). The ICG-MTX was then mixed with the hydrogel precursor and radical initiator to obtain an injectable hydrogel precursor solution. Under the irradiation of NIR light, the precursor solution could release alkyl radicals, which promote the transition of the precursor solution from a liquid to a colloidal state. As a result, the nanomedicine could effectively remain at the site of the tumor and continue to be released from the hydrogel. Due to the targeted nature of MTX, the released ICG-MTX could target tumor cells and improve the accuracy of photothermal-chemo combination therapy. The results indicated that the injectable nanomedicine-hydrogel system has a favorable therapeutic effect on tumors.

UV-vis spectroscopic detection of formaldehyde and its analogs: A convenient and sensitive methodology

Formaldehyde is deemed to be an indispensable industrial product that has been widely applied in manufacture of resins, drugs, building materials, etc. It has been widely accepted that, nevertheless, residual formaldehyde will cause pathogen reactions, even leading to cancers like leukemia. Thus, a facile and efficient approach has been designed to achieve the determination of formaldehyde by ultraviolet and visible (UV-vis) spectrophotometry in liquid media. In detail, O-(carboxymethyl) hydroxylamine (C₂H₅NO₃·0.5HCl) is chosen as the detection reagent for the specific recognition of formaldehyde on account of its unique aminooxy (-O-NH₂) which can react with formaldehyde to form oxime bonds (O-NCH₂), accompanied with the only by-product of H₂O. Likewise, this simple and sensitive detection approach based on the chemical detection reagent C₂H₅NO₃·0.5HCl can also be applied to the determination of other aldehyde homologs with carbonyl groups including acetaldehyde, acetone, benzaldehyde, 1, 4-phthalaldehyde. As a result, all the UV absorbances of analytes display remarkable linear detection relationships. The limits of detection (LOD) and limits of quantitation (LOQ) values are in the range of 0.03-1.16 ppm and 0.03-5.81 ppm respectively, with RSDs of 3.27-3.75 %, evidencing the feasibility of our method to determine formaldehyde and its homologs by UV-vis spectrophotometry and auspicious prospects of practical applications.

Research on the on-line determination of formaldehyde gas by the gas-liquid phase chemiluminescence method

Based on the gas-liquid phase chemiluminescence tester independently developed by our laboratory, a highly sensitive, fast and accurate on-line detection method of formaldehyde gas in ambient atmosphere is established. The chemiluminescence system and the trace formaldehyde gas in the air directly undergo an interface heterogeneous chemiluminescence reaction to obtain a strong chemiluminescence signal. Through the measurement of the chemiluminescence signal intensity, a highly sensitive, real-time and on-line method for the determination of formaldehyde in the air was established. Factors influencing the experimental results such as gallic acid, potassium dichromate, reaction medium concentration, surfactant type and concentration, pump speed, tube length, and interfering gas were discussed based on the single factor and orthogonal analysis results. Finally, the optimal detection conditions were collected, and the detection results were compared with the national standard phenol reagent method. The results show that when the concentration of the standard formaldehyde gas is in the range of 0-0.582 μg L-1, the linear equation of this method is y = 208x + 29.667, the linear coefficient is R 2 = 0.997, and the minimum detection concentration of formaldehyde is 2.327 × 10-3 μg L-1. Under the same external conditions, the comparison and analysis using the national standard phenol reagent method proved that this method has the advantages of fast detection speed, low detection limit, good sensitivity, and accurate results, which can be used for real-time and online determination of trace formaldehyde in ambient air.

A review of plants formaldehyde metabolism: Implications for hazardous emissions and phytoremediation

The wide use of hazardous formaldehyde (CH₂O) in disinfections, adhesives and wood-based furniture leads to undesirable emissions to indoor environments. This is highly problematic as formaldehyde is a highly hazardous and toxic compound present in both liquid and gaseous form. The majority of gaseous and atmospheric formaldehyde derive from microbial and plant decomposition. However, plants also reversibly absorb formaldehyde released from for example indoor structural materials in such as furniture, thus offering beneficial phytoremediation properties. Here we provide the first comprehensive review of plant formaldehyde metabolism, physiology and remediation focusing on release and absorption including species-specific differences for maintaining indoor environmental air quality standards. Phytoremediation depends on rhizosphere, temperature, humidity and season and future indoor formaldehyde remediation therefore need to take these biological factors into account including the balance between emission and phytoremediation. This would pave the road for remediation of formaldehyde air pollution and improve planetary health through several of the UN Sustainable Development Goals.

Progress in the Study of Optical Probes for the Detection of Formaldehyde

Formaldehyde, one of the simplest reactive carbonyl substances, is involved in many physiological and pathological processes in living organisms. There is a large amount of data showing that abnormal elevation of formaldehyde is associated with a variety of diseases in the body, such as neurodegenerative diseases, Alzheimer's disease, cardiovascular diseases and cancer, and is also a representative carcinogen, so monitoring formaldehyde is of great importance for disease diagnosis and treatment. In this review, In this paper, we summarize and classify the last ten years of probes for the detection of formaldehyde according to different reaction mechanisms and discuss the structures and applications of the probes. Finally, we briefly describe the challenges and possible solutions in this field. We believe that more new probes provide powerful tools to study the function of formaldehyde in living systems.

An Eco-Friendly Wood Adhesive Consisting of Soybean Protein and Cardanol-Based Epoxy for Wood Based Composites

Formaldehyde-derived wood adhesives have dominated in woody composites production up to now, while facing a significant challenge in non-renewable raw materials and the formaldehyde emission. To solve these problems, an eco-friendly soybean protein-based wood adhesive was explored via the addition of renewable cardanol based epoxy (CBE) as cross-linking agent. The curing mechanism and viscosity of the adhesives were investigated and the bonding performance was evaluated with three-ply plywood. Fourier transformed infrared spectroscopy (FTIR) analysis confirmed the formation of new ether linkages and the consumption of epoxy groups in the cured adhesives, thereby improving the thermal stabilities and cohesion. Plywood bonded with the CBE-modified soybean protein-based adhesive reached the maximum wet shear strength of 1.11 MPa (4 wt.% CBE addition), a 48% increase compared to the control, whereas the viscosity of adhesive decreased by 68.2%. The wet shear strength of the plywood met the requirements of the Chinese National Standard GB/T 9846-2015 for interior plywood application. The formaldehyde-free adhesive with excellent water resistance adhesiveness performance shows great potential in woody composites as an alternative to formaldehyde derived wood adhesives.

Facile Hydrothermal Synthesis of SnO2 Nanoflowers for Low-Concentration Formaldehyde Detection

In this work, SnO₂ nanoflowers were prepared by a simple one-step hydrothermal process. The morphology and structure of SnO₂ nanoflowers were characterized by SEM, TEM, Raman spectroscopy, and XRD, which demonstrated the good crystallinity of the SnO₂ tetrahedron structure of the as-synthesized materials. In addition, the sensing properties of SnO₂ nanoflowers were studied in detail. It was found that the SnO₂ nanoflower-based gas sensor exhibits excellent gas response (9.2 to 120 ppm), fast response and recovery (2/15 s to 6 ppm), good linearity of correlation between response (S) vs. concentration (C) (lgS = 0.505 lgC − 0.147, R² = 0.9863), superb repeatability, and selectivity at 300 °C. The outstanding performance can also be attributed to the high specific surface area ratio and size of SnO₂ nanoflowers close to the thickness of the electron depletion layer that can provide abundant active sites, promote the rate of interaction, and make it easier for gas molecules to diffuse into the interior of the material. Therefore, SnO₂ nanoflowers can be an ideal sensing material for real-time monitoring of low-concentration HCHO.

Gradient Porous Structured MnO2-Nonwoven Composite: A Binder-Free Polymeric Air Filter for Effective Room-Temperature Formaldehyde Removal

Recently, MnO₂-coated polymeric filters have shown promising performance in room-temperature formaldehyde abatement. However, a commonly known concern of MnO₂/polymer composites is either MnO₂ crystal encapsulation or weak adhesion. This work reports a low-cost high-throughput and green strategy to produce binder-free MnO₂-nonwoven composite air filters. The production approach is energy saving and environmentally friendly, which combines MnO₂ crystal coating on bicomponent polyolefin spunbond nonwovens and subsequent heat immobilizing of crystals, followed by the removal of weakly bonded MnO₂. The binder-free MnO₂-nonwoven composites show firm catalyst-fiber adhesion, a gradient porous structure, and excellent formaldehyde removal capability (94.5% ± 0.4%) at room temperature, and the reaction rate constant is 0.040 min⁻¹. In contrast to the MnO₂-nonwoven composites containing organic binders, the HCHO removal of binder-free filters increased by over 4%. This study proposes an alternative solution in producing catalyst/fabric composite filters for formaldehyde removal.

Toxicological Mechanism of Individual Susceptibility to Formaldehyde-Induced Respiratory Effects

Understanding the mechanisms of individual susceptibility to exposure to environmental pollutants has been a challenge in health risk assessment. Here, an integrated approach combining a CRISPR screen in human cells and epidemiological analysis was developed to identify the individual susceptibility to the adverse health effects of air pollutants by taking formaldehyde (FA) and the associated chronic obstructive pulmonary disease (COPD) as a case study. Among the primary hits of CRISPR screening of FA in human A549 cells, HTR4 was the only gene genetically associated with COPD susceptibility in global populations. However, the association between HTR4 and FA-induced respiratory toxicity is unknown in the literature. Adverse outcome pathway (AOP) network analysis of CRISPR screen hits provided a potential mechanistic link between activation of HTR4 (molecular initiating event) and FA-induced lung injury (adverse outcome). Systematic toxicology tests (in vitro and animal experiments) were conducted to reveal the HTR4-involved biological mechanisms underlying the susceptibility to adverse health effects of FA. Functionality and enhanced expression of HTR4 were required for susceptibility to FA-induced lung injury, and FA-induced epigenetic changes could result in enhanced expression of HTR4. Specific epigenetic and genetic characteristics of HTR4 were associated with the progression and prevalence of COPD, respectively, and these genetic risk factors for COPD could be potential biomarkers of individual susceptibility to adverse respiratory effects of FA. These biomarkers could be of great significance for defining subpopulations susceptible to exposure to FA and reducing uncertainty in the next-generation health risk assessment of air pollutants. Our study delineated a novel toxicological pathway mediated by HTR4 in FA-induced lung injury, which could provide a mechanistic understanding of the potential biomarkers of individual susceptibility to adverse respiratory effects of FA.

Formalin-free soft embalming of human cadavers using N-vinyl-2-pyrrolidone: perspectives for cadaver surgical training and medical device development

The traditional apprenticeship approach to surgical skill education for young surgeons has drastically changed to more systematic surgical training using cadavers. Cadavers fixed with formalin are not suitable for surgical training because of their associated health hazards and overhardening. Recently, we established a formalin-free soft preservation method for human cadavers using N-vinyl-2-pyrrolidone. Since 2012, 61 cadavers have been embalmed with pyrrolidone in our institution. Tissues of pyrrolidone-embalmed cadavers are soft and pliable, and their bodies can be preserved for as long as 37 months without any signs of corruption. In this review, we introduce our recent attempts to apply pyrrolidone-embalmed cadavers in surgical and medical procedure training, including endotracheal intubation, motion physiology of the vocal folds, laparoscopic surgery, endoscopic skull base surgery, and development of novel medical devices. Future research perspectives on pyrrolidone embalming are discussed.

Combinative ex vivo studies and in silico models ProTox-II for investigating the toxicity of chemicals used mainly in cosmetic products

Human data on remains sparse and of varying quality and reproducibility. Ex vivo experiments and animal experiments currently is the most preferred way to predict the skin sensitization approved by the regulatory agencies across the world. However, there is a constant need and demand to reduce animal experiments and provide the scope of alternative methods to animal testing. In this study, we have compared the predictive performance of the published computational tools such as ProTox-II, SuperCYPsPred with the data obtained from ex-vivo experiments. From the results of the retrospective analysis, it can be observed that the computational predictions are in agreement with the experimental results. The computational models used here are generative models based on molecular structures and machine learning algorithms and can be applied also for the prediction of skin sensitization. Besides prediction of the toxicity endpoints, the models can also provide deeper insights into the molecular mechanisms and adverse outcome pathways (AOPs) associated with the chemicals used in cosmetic products.

Diurnal variation and potential sources of indoor formaldehyde at elementary school, high school and university in the Centre Val de Loire region of France

Formaldehyde (HCHO) is one of the abundant indoor pollutants and has been classified as a human carcinogen by the International Agency for Research on Cancer (IARC). Indoor HCHO at schools is particularly important due to the high occupancy density and the health effects on children. In this study, high time resolved measurement of formaldehyde concentration was conducted in the classrooms at elementary school, high school and university under normal students' activities in three different locations in the Region Centre Val de Loire-France. Indoor average formaldehyde concentrations at those three educational institutions were observed to be in the range 10.96-17.95 μg/m³, not exceeding the World Health Organization (WHO) guideline value of 100 μg/m³. As expected, ventilation was found playing an important role in the control of indoor formaldehyde concentration. After opening windows for 30 min, formaldehyde level decreased by ~25% and 38% in the classroom at the elementary school and the high school, respectively. In addition to the primary sources, the objective of this study was also to determine potential secondary sources of indoor formaldehyde in these schools by measuring the other volatile organic compounds (VOCs) present in the classrooms by a Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS). The measurements suggest that the release of residue from tobacco smokers is one of the major sources of indoor HCHO at the high school, which increases HCHO by ~55% averagely within 1 h. Moreover, the control experiments conducted in the university suggests that VOCs such as that released from cleaning products like terpenes, can contribute to the increase of indoor formaldehyde levels through chemical reactions with ozone. This study confirms simple recommendations to reduce the indoors HCHO concentration in schools: use ventilation systems, limit the emissions like cigarette smoke or cleaning products. It also points out that the secondary sources of formaldehyde must be also considered in the classroom.

Investigation of indoor air quality in university libraries in terms of gaseous and particulate pollutants in Bartin, Turkey

Indoor air quality (IAQ) was investigated in two libraries of Bartin University. Particle matter, TVOC, and CH₂O were measured simultaneously in different rooms of the libraries. Measurements were made by PCE-RCM 11 measuring device. They were conducted monthly between September 2019 and October 2020 for 2 weeks for each library. TVOC mean concentration was higher than the limit value reported by Seifert et al. (1999). PM_2.5 and PM₁₀ concentrations were higher in winter unlike TVOC and CH₂O concentrations. The indoor seconder blowing dust was detected to be the most important source of particulate matter in the indoor environment. On the other hand, it was thought that the pollutants in the gas phase were affected by indoor and outdoor air temperature, indoor/outdoor air exchange rate, and indoor/outdoor pollutant sources. The parameters changed during the day and in different rooms of the libraries. Pollutants did not pose any hazard on human health, since the calculated HQ and HI ≤ 1 for both exposure groups. The indoor air of the libraries was detected to be slightly polluted and bad according to the IAQI and IEI, respectively. On the other hand, the indoor air quality of the libraries was good in terms of all parameters according to the IAQC.

Exploring the photocatalytic conversion mechanism of gaseous formaldehyde degradation on TiO2-x-OV surface

To understand the conversion mechanism of photocatalytic gaseous formaldehyde (HCHO) degradation, strontium (Sr)-doped TiO_2-x-OV catalysts was designed and synthesized in this study, with comparable HCHO removal performance. Our results proved that foreign-element doping reduced Ti⁴⁺ to the lower oxidation state Ti^{(4- x)+}, and that the internal charge kinetics was largely facilitated by the unbalanced electron distribution. Oxygen vacancies (OVs) were developed spontaneously to realize an electron-localized phenomenon in TiO_2-x-OV, thereby boosting O₂ adsorption and activation for the enhanced generation of reactive oxygen species (ROS). At the chemisorption stage, in-situ DRIFTS spectra and density functional theory calculation results revealed that surface adsorbed O₂ (O_ads) and lattice O (O_lat) engaged in the isomerisation of HCHO to dioxymethylene (DOM) on TiO_2-x-OV and TiO₂, respectively. Time-resolved DRIFTS spectra under light irradiation revealed that the DOM was then converted to formate and thoroughly oxidized to CO₂ and H₂O in TiO_2-x-OV. While bicarbonate byproducts were detected from DOM hydroxylation or possible side conversion of CO₂ in TiO₂, owing to insufficient consumption of surface hydroxyl. Our study enhances the understanding on the photocatalytic oxidation of HCHO, thereby promoting the practical application in indoor air purification.

Advances in preparation, mechanism and applications of graphene quantum dots/semiconductor composite photocatalysts: A review

Due to the low efficiency of single-component nano materials, there are more and more studies on high-efficiency composites. As zero dimensional (0D) non-metallic semiconductor material, the emergence of graphene quantum dots (GQDs) overcomes the shortcomings of traditional photocatalysts (rapid rate of electron-hole recombination and narrow range of optical response). Their uniqueness is that they can combine the advantages of quantum dots (rich functional groups at edge) and sp² carbon materials (large specific surface area). The inherent inert carbon stabilizes chemical and physical properties, and brings new breakthroughs to the development of benchmark photocatalysts. The photocatalytic efficiency of GQDs composite with semiconductor materials (SCs) can be improved by the following three points: (1) accelerating charge transfer, (2) extending light absorption range, (3) increasing active sites. The methods of preparation (bottom-up and top-down), types of heterojunctions, mechanisms of photocatalysis, and applications of GQDs/SCs (wastewater treatment, energy storage, gas sensing, UV detection, antibiosis and biomedicine) are comprehensively discussed. And it is hoped that this review can provide some guidance for the future research on of GQDs/SCs on photocatalysis.

Formaldehyde, acrolein and other carbonyls in dwellings of university students. Levels and source characterization

Fifteen carbonyl compounds were investigated in the living rooms and bedrooms of 25 university student flats in the urban area of Ciudad Real (Central Southern Spain) in wintertime. Carbonyls were sampled using Radiello ® passive samplers refilled in the laboratory according to the method described in ISO 16000-3 Standard. The most abundant carbonyls in the living rooms and bedrooms were formaldehyde, acetone, acetaldehyde, hexaldehyde and butyraldehyde. The median concentration levels in the living rooms and bedrooms were: 28.6 and 34.2 μg m^-3 for formaldehyde, 18.3 and 23.1 μg m^-3 for acetone, 14.3 and 15.8 μg m^-3 for acetaldehyde, 11.4 and 14.1 μg m^-3 for hexaldehyde and 10.8 and 12.4 μg m^-3 for butyraldehyde. The median concentration of formaldehyde, benzaldehyde, valeraldehyde and hexaldehyde was significantly higher in the bedrooms than in the living rooms. Indoor concentrations were significantly higher than outdoor concentrations for all carbonyl measured, indicating that sources in the indoor environment are prevailing in all flats. Principal component analysis, multiple linear regressions and Spearman correlation coefficients were used to investigate the origin, the indoor pollutants determinants and to establish common sources between carbonyls. Eight components were extracted from the application of PCA to the indoor and outdoor measurements accounting for 97.7% of the total variance. Formaldehyde, acetone, acetaldehyde and acrolein presented different indoor sources. In the multiple linear regression analysis, higher formaldehyde concentrations were found in those living rooms with wood floor and smoking was positively associated to acetone, propionaldehyde, benzaldehyde and isovaleraldehyde. Formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde and benzaldehyde concentrations were compared with relevant international guidelines, being their concentrations below recommended values except acrolein, where all measured flats exceeded the reference levels; it would be important to focus on the characterization of emission sources of acrolein in indoor air in order to minimise the exposure and health risk.

Will open waste burning become India's largest air pollution source?

India struggles with frequent exceedances of the ambient air quality standard for particulate matter and benzene. In the past two decades, India has made considerable progress in tackling indoor air pollution, by phasing out kerosene lamps, and pushing biofuel using households towards Liquefied Petroleum Gas (LPG) usage. In this study, we use updated emission inventories and trends in residential fuel consumption, to explore changes in the contribution of different sectors towards India's largest air pollution problem. We find that residential fuel usage is still the largest air pollution source, and that the <10% households using cow dung as cooking fuel contribute ∼50% of the residential PM_2.5 emissions. However, if current trends persist, residential biofuel usage in India is likely to be phased out by 2035. India's renewable energy policies are likely to reduce emissions in the heat and electricity sector, and manufacturing industries, in the mid-term. PM_2.5 emissions from open waste burning, on the other hand, hardly changed in the decade from 2010 to 2020. We conclude that without strong policies to promote recycling and upcycling of non-biodegradable waste, and the conversion of biodegradable waste to biogas, open waste burning is likely to become India's largest source of air pollution by 2035. While our study is limited to India, our findings are of relevance for other countries in the global South suffering from similar waste management challenges.

Cr-Doped Pd Metallene Endows a Practical Formaldehyde Sensor New Limit and High Selectivity

Electrochemical sensors for detecting micromolecule organics are desirable for improving the perception of environmental quality and human health. However, currently, the electrochemical sensors for formaldehyde are substantially limited on the market due to the long-term unsolved problems of the low electrooxidation efficiency and CO poisoning issue of commercial Pd catalysts. Here, a 2D Cr-doped Pd metallene (Cr-Pdene) with few atomic layers is shown as an advanced catalyst for ultrasensitive and selective sensing of formaldehyde via a highly efficient formaldehyde electrooxidation. It is found that the doping of Cr into Pd metallene can efficiently optimize the electronic structure of Pd and weaken the interaction between Pd and CO, providing an anti-poisoning means to favor CO₂ production and suppress CO adsorption. The Cr-Pdene-based electrochemical sensor exhibits one order of magnitude higher detection range and, especially, much higher anti-interference for formaldehyde than that of the conventional sensors. Most importantly, it is demonstrated that the Cr-Pdene can be integrated into commercializable wireless sensor networks or handheld instruments for promising applications relating to the environment, health, and food.

Occupational scenarios and exposure assessment to formaldehyde: A systematic review

The objectives of the systematic review were to: identify the work sectors at risk for exposure to formaldehyde; investigate the procedures applied to assess occupational exposure; evaluate the reported exposure levels among the different settings. An electronic search of Pubmed, Scopus, Web of Science and ToxNet was carried out for collecting all the articles on the investigated issue published from January 1, 2004 to September 30, 2019. Forty-three papers were included in the review, and evidenced a great number of occupational scenarios at risk for formaldehyde exposure. All the included studies collected data on formaldehyde exposure levels by a similar approach: environmental and personal sampling followed by chromatographic analyses. Results ranged from not detectable values until to some mg m^-3 of airborne formaldehyde. The riskiest occupational settings for formaldehyde exposure were the gross anatomy and pathology laboratories, the hairdressing salons and some specific productive settings, such as wooden furniture factories, dairy facilities and fish hatcheries. Notice that formaldehyde, a well-known carcinogen, was recovered in air at levels higher than outdoor in almost all the studied scenarios/activities; thus, when formaldehyde cannot be removed or substituted, targeted strategies for exposure elimination or mitigation must be adopted.

Association Between Occupational Exposure to Formaldehyde and Cognitive Impairment

OBJECTIVE

To our knowledge, no study has investigated the effect of exposure to formaldehyde on cognition in the general population. Our objective was to examine the association between occupational exposure to formaldehyde and cognitive impairment in middle-aged and young- old adults (≥45 years).

METHODS

In the French CONSTANCES cohort, cognitive function was assessed with a standardized battery of seven cognitive tests to evaluate global cognitive function, episodic verbal memory, language abilities and executive functions (e.g., Digit Symbol Substitution Test, DSST). A global cognitive score was created using principal component analysis. Cognitive impairment was assessed in reference to norms of neuropsychological battery according to age, sex and education. Lifetime exposure to formaldehyde was assessed using a French job-exposure matrix created in the framework of the Matgéné project. After performing multiple imputation, separate modified Poisson regression models were used to evaluate the association between cognitive impairment (<25^th percentile) and formaldehyde exposure (exposed/never exposed), exposure duration, cumulative exposure index (CEI), and combination of CEI and time of last exposure.

RESULTS

Among 75 322 participants (median age: 57.5 years, women: 53%), 8% were exposed to formaldehyde during their professional life. These participants were at higher risk of global cognitive impairment (for global cognitive score: adjusted relative risk, aRR, 1.17, 95% confidence interval, CI: 1.11-1.23), after adjusting for confounders (age, sex, education, income, solvent exposure, Effort-Reward Imbalance, night-shift, repetitive, and noisy work). They were at higher risk of cognitive impairment for all cognitive domains explored. Longer exposure duration and high CEI were associated with cognitive impairment, with a dose-effect relationship for exposure duration. Recent exposure was associated with impairment in all cognitive domains. Time did not fully attenuate formaldehyde-associated cognitive deficits especially in highly exposed individuals (for DSST: high past exposure aRR 1.23, 95%CI: 1.11-1.36; high recent exposure: aRR 1.24, 95%CI: 1.13-1.35).

CONCLUSION

Our findings highlight the long-term detrimental effect of formaldehyde exposure on cognitive health in a relatively young population.

A Call for Change. Can 3D Printing Replace Cadavers for Surgical Training?

While cadaveric dissection has stood the test of time because of its widely accepted educational value by experienced surgeons, the introduction advances in 3D printing and biomaterial technologies could potentially provide alternative tools for surgical training. This novel concept in simulation (physical reality) would encompass all the benefits of cadavers in terms of realism and clinical relevance without any of its ethical, infection, safety, and financial concerns.

PVA-SM microstructure enhanced ratiometric fluorescence probe for formaldehyde detection in solution and gas

Formaldehyde (FA) is one of the most common pollutants, which has tremendous harm to humans and environment. In this work, 4-amino-3-pentene-2-one (Fluoral-p) and SiO₂ coated quantum dot (QD@SiO₂) were combined to implement a new ratiometric fluorescence probe QD@SiO₂-Fluoral-p for FA detection. In addition, by utilization of polyvinyl alcohol (PVA) and SiO₂ microsphere (SM), a kind of PVA-SM microstructure was assembled with QD@SiO₂-Fluoral-p to composite a signal enhanced sensing film. The QD@SiO₂-Fluoral-p exhibited good response to 0-400 mg/L FA solution and an enhancement around 15 folds was realized after introducing PVA-SM. In both situations, the probe showed linear relationship to FA concentration (C_FA), with detection limits of 14 and 0.5 mg/L, respectively. Also, the sensing film showed a good linear response to FA gas in the range of 0 to 2 ppm, with a detection limit 0.03 ppm. As a result, the PVA-SM enhanced ratiometric fluorescence probe features high sensitivity, low detection limit, good selectivity, as well as portable, which can serve as a useful tool for investigating FA in solution and gas at room temperature.

Photocatalytic oxidation technology for indoor air pollutants elimination: A review

As more people are spending the majority of their daily lives indoors, indoor air quality has been acknowledged as an important factor influencing human health, with increasing research attention in recent decades. Indoor air pollutants (IAPs), such as volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs), can cause acute irritation and chronic diseases. Photocatalytic oxidation (PCO) technology is an efficient approach for eliminating IAPs. In this review, the development of PCO technology was explained and discussed to promote future development of PCO technology for IAP elimination. First, the health effects and the measured concentrations of typical VOCs and SVOCs in indoor environments worldwide were briefly introduced. Subsequently, the development and limitations of some typical photocatalytic reactors (including packed-bed reactors, monolithic reactors, optical fiber reactors, and microreactors) were summarized and compared. Then, the influences of operating parameters (including initial concentration of contaminants, relative humidity, space velocity, light source and intensity, catalyst support materials, and immobilization method) and the degradation pathways as well as intermediates of PCO technology were elucidated. Finally, the possible challenges and future development directions regarding PCO technology for IAP elimination were critically proposed and addressed.

Low Temperature HCHO Detection by SnO2/TiO2@Au and SnO2/TiO2@Pt: Understanding by In-Situ DRIFT Spectroscopy

In this work we analyze the effectiveness of decoration of nanocrystalline SnO2/TiO2 composites with gold nanoparticles (Au NPs) and platinum nanoparticles (Pt NPs) in enhancing gas sensor properties in low-temperature HCHO detection. Nanocrystalline SnO2/TiO2 composites were synthesized by a chemical precipitation method with following modification with Pt and Au NPs by the impregnation method. The nanocomposites were characterized by TEM, XRD, Raman and FTIR spectroscopy, DRIFTS, XPS, TPR-H2 methods. In HCHO detection, the modification of SnO2 with TiO2 leads to a shift in the optimal temperature from 150 to 100 °C. Further modification of SnO2/TiO2 nanocomposites with Au NPs increases the sensor signal at T = 100 °C, while modification with Pt NPs gives rise to the appearance of sensor responses at T = 25 °C and 50 °C. At 200 °C nanocomposites exhibited high selectivity toward formaldehyde within the sub-ppm concentration range among different VOCs. The influence of Pt and Au NPs on surface reactivity of SnO2/TiO2 composite and enhancement of the sensor response toward HCHO was studied by DRIFT spectroscopy and explained by the chemical and electronic sensitization mechanisms.

Formaldehyde in Hospitals Induces Oxidative Stress: The Role of GSTT1 and GSTM1 Polymorphisms

Despite the toxicity and health risk characteristics of formaldehyde (FA), it is currently used as a cytological fixative and the definition of safe exposure levels is still a matter of debate. Our aim was to investigate the alterations in both oxidative and inflammatory status in a hospital working population. The 68 workers recruited wore a personal air-FA passive sampler, provided a urine sample to measure 15-F_2t-Isoprostane (15-F_2t-IsoP) and malondialdehyde (MDA) and a blood specimen to measure tumour necrosis factor α (TNFα). Subjects were also genotyped for GSTT1 (Presence/Absence), GSTM1 (Presence/Absence), CYP1A1 exon 7 (A > G), and IL6 (−174, G > C). Workers were ex post split into formalin-employers (57.3 μg/m³) and non-employers (13.5 μg/m³). In the formalin-employers group we assessed significantly higher levels of 15-F_2t-IsoP, MDA and TNFα (<0.001) in comparison to the non-employers group. The air-FA levels turned out to be positively correlated with 15-F_2t-IsoP (p = 0.027) and MDA (p < 0.001). In the formalin-employers group the MDA level was significantly higher in GSTT1 Null (p = 0.038), GSTM1 Null (p = 0.031), and CYP1A1 exon 7 mutation carrier (p = 0.008) workers, compared to the wild type subjects. This study confirms the role of FA in biomolecular profiles alterations, highlighting how low occupational exposure can also result in measurable biological outcomes.

Strategies for Improving the Sensing Performance of Semiconductor Gas Sensors for High-Performance Formaldehyde Detection: A Review

Formaldehyde is a poisonous and harmful gas, which is ubiquitous in our daily life. Long-term exposure to formaldehyde harms human body functions; therefore, it is urgent to fabricate sensors for the real-time monitoring of formaldehyde concentrations. Metal oxide semiconductor (MOS) gas sensors is favored by researchers as a result of their low cost, simple operation and portability. In this paper, the mechanism of formaldehyde detection by gas sensors is introduced, and then the ways of ameliorating the response of gas sensors for formaldehyde detection in recent years are summarized. These methods include the control of the microstructure and morphology of sensing materials, the doping modification of matrix materials, the development of new semiconductor sensing materials, the outfield control strategy and the construction of the filter membrane. These five methods will provide a good prerequisite for the preparation of better performing formaldehyde gas sensors.

TiO2hierarchical nano blooming-flower decorated by Pt for formaldehyde detection

To achieve an ultra-low concentration formaldehyde detection at low temperature, a platinum (Pt) assisted TiO₂hierarchical nano blooming-flower sphere material is synthesized through hydrothermal method. SEM and transmission electron microscope characterizations show that the diameter of the nano sphere was around 2μm with dissilient rods of 60 nm in diameter and 1μm in length on the surface. The response (R_a/R_g) achieved form this nanomaterial to HCHO is 1.08 (100 ppb) and 5.82 (5 ppm) at 130 °C without an involvement of any light source or solution. The relationship curve between the responses and concentrations shows regular exponential trend. The verification of sensor stability done by a 3 month reliability test shows no response-degradation. The optimal response and stability is attributed to the massive dissilient rods on the surface of TiO₂spheres and the assistance of Pt as a catalyzer disperses to intensify the formation of depletion area on the surface of TiO₂. This study provide an attractive and cost effective solution for the detection of HCHO in air at a relatively low temperature.

An Upgrade of Apparatus and Measurement Systems for Generation of Gaseous Formaldehyde: A Review

Formaldehyde (FA) is ubiquitous in the atmospheric environment. It is generally the dominant atmospheric carbonyl compound. Due to its well-known carcinogenicity, FA is a compound that arises the attention in the scientific community. In studies concerning the toxicological effects of FA on humans, animals, and the environment, testing and calibration of air sampling systems and analytical instruments are pivotal. Therefore, the preparation of controllable standard gaseous atmospheres containing FA at levels known with precision and accuracy is essential. This review summarizes the procedures for generating the FA atmosphere, given that operative solutions have been evolving recently. Furthermore, an overview on the available system to collect and store gaseous standard is reported. The progressively implemented FA generation techniques, together with commercially-available instruments, are herein described, classified, and compared.

Long-term residential exposure to air pollution and Hodgkin lymphoma risk among adults in Denmark: a population-based case-control study

PURPOSE

The etiology of Hodgkin lymphoma (HL) is obscure. Research on air pollution and risk of HL provides inconsistent results. We aimed to investigate the association between long-term residential exposure to air pollution and risk of adult Hodgkin lymphoma in Denmark.

METHODS

We performed a nationwide register-based case-control study, including all (n = 2,681) Hodgkin lymphoma cases registered in the nationwide Danish Cancer Registry between 1989 and 2014. We randomly selected 8,853 age- and sex-matched controls from the entire Danish population using the Civil Registration System, and identified 20-year residential address history for all cases and controls. We modeled outdoor air pollution concentrations at all these addresses using the high-resolution multiscale air pollution model system DEHM/UBM/AirGIS. We used conditional logistic regression to estimate odds ratios adjusted for individual and neighborhood level sociodemographic variables.

RESULTS

There was no association between 1, 5, 10, and 20 years' time-weighted average exposure to fine particles (PM_2.5), O₃, SO_2, NO_2, or the PM_2.5 constituents OC, NH₄, NO₃, and SO₄ and risk of Hodgkin lymphoma.

CONCLUSION

Residential exposure to ambient air pollution does not seem to increase the risk of developing Hodgkin lymphoma.

The role of phase I, phase II, and DNA-repair gene polymorphisms in the damage induced by formaldehyde in pathologists

Formaldehyde (FA) is a human carcinogen used as formalin in hospital laboratories. We evaluated its association with human chromosomal aberrations (CAs) and the risk/protective role played by several genetic polymorphisms in this relationship, on a cohort of 57 exposed pathologists vs 48 controls. All subjects were assessed for CAs on peripheral blood lymphocytes and genotyped for the most common cancer-associated gene polymorphisms which could be related with the genotoxic outcome: CYP1A1 exon 7 (A>G), CYP1A1*2A (T>C), CYP2C19*2 (G>A), GSTT1 (Positive/Null), GSTM1 (Positive/null), GSTP1 (A>G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPD (A751C), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα - 308 (G>A), IL10 - 1082 (G>A), IL10 - 819 (C>T) and IL6 - 174 (G>C). Air-FA concentration was assessed through personal samplers. The comparison between pathologists and controls showed a significantly higher CAs frequency in pathologists. Significant positive correlations were found between CAs frequency and air-FA concentration while significant associations were found between variation in CAs frequency and the mutated allele for CYP1A1 exon 7 (A>G), CYP2C19*2 (G>A), GSTT1-positive, GSTM1-positive and XRCC1 (G399A). Our study confirms the role of FA as genotoxicity inductor, even in workers chronically exposed to low air-FA levels and reveals the role played by some genetic polymorphisms in this association, highlighting the importance of individual susceptibility biomarkers assessment in occupational health studies.

Current State of Indoor Air Phytoremediation Using Potted Plants and Green Walls

Urban civilization has a high impact on the environment and human health. The pollution level of indoor air can be 2–5 times higher than the outdoor air pollution, and sometimes it reaches up to 100 times or more in natural/mechanical ventilated buildings. Even though people spend about 90% of their time indoors, the importance of indoor air quality is less noticed. Indoor air pollution can be treated with techniques such as chemical purification, ventilation, isolation, and removing pollutions by plants (phytoremediation). Among these techniques, phytoremediation is not given proper attention and, therefore, is the focus of our review paper. Phytoremediation is an affordable and more environmentally friendly means to purify polluted indoor air. Furthermore, studies show that indoor plants can be used to regulate building temperature, decrease noise levels, and alleviate social stress. Sources of indoor air pollutants and their impact on human health are briefly discussed in this paper. The available literature on phytoremediation, including experimental works for removing volatile organic compound (VOC) and particulate matter from the indoor air and associated challenges and opportunities, are reviewed. Phytoremediation of indoor air depends on the physical properties of plants such as interfacial areas, the moisture content, and the type (hydrophobicity) as well as pollutant characteristics such as the size of particulate matter (PM). A comprehensive summary of plant species that can remove pollutants such as VOCs and PM is provided. Sources of indoor air pollutants, as well as their impact on human health, are described. Phytoremediation and its mechanism of cleaning indoor air are discussed. The potential role of green walls and potted-plants for improving indoor air quality is examined. A list of plant species suitable for indoor air phytoremediation is proposed. This review will help in making informed decisions about integrating plants into the interior building design.