Characteristics and influencing factors of airborne microplastics in nail salons

Influence of agricultural activity in corn farming on airborne microplastic in surrounding elementary school

Microplastics (MPs) have been widely detected in agricultural soils, and agricultural activities have been identified as an important factor influencing the abundance of MPs in the air. However, no studies have investigated whether agricultural activities are contributors to airborne MPs in buildings near farms. We collected airborne MP samples using an active sampling method from an elementary school near corn farms during different cultivation stages to assess the impact of agricultural activities on MPs in the study school near farms. Our data showed that the predominant shapes, sizes, colors, and polymer compositions were fragments, 2-50 μm, black or grey, and polyethylene terephthalate, respectively, during all cultivation stages. The highest and lowest MP concentrations were recorded during the land preparation (56.8 ± 7.4 particles/m3, August 2022) and growth (2.5 ± 1.8 particles/m3, February 2022) stages, respectively. A multiple-path particle dosimetry model revealed that the deposition fractions of MPs in humans were highest in the head; the highest and lowest deposition rates and fluxes of MPs in the airway were found during the land preparation and growth stages, respectively. The concentration of MPs did not present a positive correlation with potassium or crustal elemental concentration; however, it did show a positive association with temperature value. Therefore, our data did not show that corn cultivation influences MP concentrations in the study school near corn farms; instead, temperature was an important influencing factor.

Transforming pollution into solutions: A bibliometric analysis and sustainable strategies for reducing indoor microplastics while converting to value-added products

Microplastics (MPs), as emerging indoor contaminants, have garnered attention due to their ubiquity and unresolved implications for human health. These tiny particles have permeated indoor air and water, leading to inevitable human exposure. Preliminary evidence suggests MP exposure could be linked to respiratory, gastrointestinal, and potentially other health issues, yet the full scope of their effects remains unclear. To map the overall landscape of this research field, a bibliometric analysis based on research articles retrieved from the Web of Science database was conducted. The study synthesizes the current state of knowledge and spotlights the innovative mitigation strategies proposed to curb indoor MP pollution. These strategies involve minimizing the MP emission from source, advancements in filtration technology, aimed at reducing the MP exposure. Furthermore, this research sheds light on cutting-edge methods for converting MP waste into value-added products. These innovative approaches not only promise to alleviate environmental burdens but also contribute to a more sustainable and circular economy by transforming waste into resources such as biofuels, construction materials, and batteries. Despite these strides, this study acknowledges the ongoing challenges, including the need for more efficient removal technologies and a deeper understanding of MPs' health impacts. Looking forward, the study underscores the necessity for further research to fill these knowledge gaps, particularly in the areas of long-term health outcomes and the development of standardized, reliable methodologies for MP detection and quantification in indoor settings. This comprehensive approach paves the way for future exploration and the development of robust solutions to the complex issue of microplastic pollution.

Microplastics suspended in dust from different indoor environments in Barranquilla, Colombia: Predominant microparticles?

Considering that microplastics (MPs) are classified as ubiquitous pollutants, that air quality affects human health, and that people remain indoors most of the time, the need has arisen to evaluate the exposure to MPs within the suspended dust in indoor environments. With this objective, the present study carried out passive sampling to analyze the precipitation of microparticles in some indoor residential environments (2 apartments) and workplaces (an office, a pastry shop, a gift shop, and a paint shop) in Barranquilla, Colombia. The quantification and physical characterization of microparticles were carried out under a stereomicroscope, and the chemical characterization was carried out by infrared microspectroscopy (μFTIR). The highest average concentration of MPs in the apartments was found in the air-conditioned rooms (1.1 × 104 MP/m2/day), and concerning the workplaces, the gift shop and the paint shop were the spaces with a higher proportion of MPs (6.0-6.1 × 103 MP/m2/day), with polyesters being the main synthetic polymers, but being semi-synthetic particles the predominant among the samples. Regarding its morphology, fibers were the most abundant shape (>90%), grouping mainly in the 1000-5000 μm range, while the few fragments found were mostly grouped below 50 μm. Exposure by inhalation of MPs in adults was estimated between 1.7 × 102-1.6 × 103 MP/kg/day, while by ingestion it ranged between 2.7 × 102-2.4 × 103 MPs/kg/day. On the other hand, within our research, a significant presence of non-plastic microparticles was found, which reached up to 69% in analyzed samples, corresponding mainly to cotton and cellulose, so we suggest that these should also be included in future studies that aim to estimate potential health implications from exposure to suspended micropollutants.

Probabilistic Estimation of Airborne Micro- and Nanoplastic Intake in Humans

Little research exists on the magnitude, variability, and uncertainty of human exposure to airborne micro- and nanoplastics (AMNPs), despite their critical role in human exposure to MNPs. We probabilistically estimate the global intake of AMNPs through three main pathways: indoor inhalation, outdoor inhalation, and ingestion during indoor meals, for both children and adults. The median inhalation of AMPs is 1,207.7 (90% CI, 42.5-8.48 × 104) and 1,354.7 (90% CI, 47.4-9.55 × 104) N/capita/day for children and adults, respectively. The annual intake of AMPs is 13.18 mg/capita/a for children and 19.10 mg/capita/a for adults, which is approximately one-fifth and one-third of the mass of a standard stamp, assuming a consistent daily intake of medians. The majority of AMP number intake occurs through inhalation, while the ingestion of deposited AMPs during meals contributes the most in terms of mass. Furthermore, the median ANP intake through outdoor inhalation is 9,638.1 N/day (8.23 × 10-6 μg/d) and 5,410.6 N/day (4.62 × 10-6 μg/d) for children and adults, respectively, compared to 5.30 × 105 N/day (5.79 × 10-4 μg/d) and 6.00 × 105 N/day (6.55 × 10-4 μg/d) via indoor inhalation. Considering the increased toxicity of smaller MNPs, the significant number of ANPs inhaled warrants great attention. Collaborative efforts are imperative to further elucidate and combat the current MPN risks.

ROS-dependent degeneration of human neurons induced by environmentally relevant levels of micro- and nanoplastics of diverse shapes and forms

Our study explores the pressing issue of micro- and nanoplastics (MNPs) inhalation and their subsequent penetration into the brain, highlighting a significant environmental health concern. We demonstrate that MNPs can indeed penetrate murine brain, warranting further investigation into their neurotoxic effects in humans. We then proceed to test the impact of MNPs at environmentally relevant concentrations, with focusing on variations in size and shape. Our findings reveal that these MNPs induce oxidative stress, cytotoxicity, and neurodegeneration in human neurons, with cortical neurons being more susceptible than nociceptors. Furthermore, we examine the role of biofilms on MNPs, demonstrating that MNPs can serve as a vehicle for pathogenic biofilms that significantly exacerbate these neurotoxic effects. This sequence of investigations reveals that minimal MNPs accumulation can cause oxidative stress and neurodegeneration in human neurons, significantly risking brain health and highlights the need to understand the neurological consequences of inhaling MNPs. Overall, our developed in vitro testing battery has significance in elucidating the effects of environmental factors and their associated pathological mechanisms in human neurons.

Critical review on airborne microplastics: An indoor air contaminant of emerging concern

Airborne Microplastics (MPs), an emerging environmental issue, have gained recent attention due to their newfound presence in indoor environments. Utilizing the Web of Science database for literature collection, the paper presents a comprehensive review of airborne MPs including emission sources, assessment methods, exposure risks, and mitigation strategies. This review delves into the diverse sources and mechanisms influencing indoor airborne MP pollution, underscoring the complex interplay between human activities, ventilation systems, and the characteristics of indoor environments. Major sources include the abrasion of synthetic textiles and the deterioration of flooring materials, with factors like carpeting, airflow, and ventilation significantly impacting MP levels. Human activities, such as increased movement in indoor spaces and the intensive use of plastic-based personal protective equipment (PPE) post-pandemic, notably elevate indoor MP concentrations. The potential health impacts of airborne MPs are increasingly concerning, with evidence suggesting their role in respiratory, immune, and nervous system diseases. Despite this, there is a scarcity of information on MPs in diverse indoor environments and the inhalation risks associated with the frequent use of PPE. This review also stresses the importance of developing effective strategies to reduce MP emissions, such as employing HEPA-filtered vacuums, minimizing the use of synthetic textiles, and enhancing indoor ventilation. Several future research directions were proposed, including detailed temporal analyses of indoor MP levels, interactions of MP with other atmospheric pollutants, the transport dynamics of inhalable MPs (≤10 μm), and comprehensive human exposure risk assessments.

Systematic review of microplastics and nanoplastics in indoor and outdoor air: identifying a framework and data needs for quantifying human inhalation exposures

BACKGROUND

Humans are likely exposed to microplastics (MPs) in a variety of places including indoor and outdoor air. Research to better understand how exposure to MPs correlates to health is growing. To fully understand the possible impacts of MPs on human health, it is necessary to quantify MP exposure and identify what critical data gaps exist.

OBJECTIVES

The current paper provides a human exposure assessment of microplastics in the air using systematically reviewed literature that provided concentration of MPs in air as well as doses used in toxicology studies to calculate inhalation exposure dose.

METHODS

All published peer-reviewed journal articles, non-published papers, and grey literature that focused on micro- or nano-plastics in indoor and outdoor air were systematically searched using PRISMA guidelines. Literature that defined specific concentrations and size of MPs in air or exposed to human lung cells, animals, or humans with measurable health impacts were included in data extraction. Inhalational exposures were calculated for different age groups using published MP concentrations from the included literature using exposure dose equations and values from U.S. ATSDR and EPA.

RESULTS

Calculated mean indoor inhalational exposures from passive sampling methods were higher than those calculated from active sampling methods. When comparing indoor and outdoor sampling, calculated inhalation exposures from indoor samples were greater than those from outdoor samples. Inhalation exposures of MPs differed between age groups with infants having the highest calculated dose values for all locations followed by preschool age children, middle-school aged children, pregnant women, adolescents, and non-pregnant adults. MP doses used in toxicology studies produced higher calculated mean inhalational exposures than those from environmental samples.

IMPACT

This study is the first known systematic review of inhalational MP exposure from indoor and outdoor air. It also provides inhalational exposures calculated from previously published environmental samples of MPs as well as from toxicology studies.

Underestimated activity-based microplastic intake under scenario-specific exposures

Despite increasing alarms over the health impacts of microplastics (MPs) due to their detection in human organs and feces, precise exposure evaluations remain scarce. To comprehend their risks, there is a distinct need to prioritize quantitive estimates in MP exposome, particularly at the environmentally-realistic level. Here we used a method rooted in real-world MP measurements and activity patterns to determine the daily intake of MPs through inhalation and from ground dust/soil ingestion. We found that nearly 80% of this intake comes from residential sectors, with activity intensity and behavioral types significantly affecting the human MP burden. The data showed a peak in MP exposure for those aged 18-64. When compared to dietary MP intake sources like seafood, salt, and water, we identified a previously underestimated exposure from inhalation and dust/soil ingestion, emphasizing the need for more realistic evaluations that incorporate activity factors. This discovery raises questions about the accuracy of past studies and underscores MP's potential health risks. Moreover, our time-based simulations revealed increased MP intake during the COVID-19 lockdown due to more surface dust ingestion, shedding light on how global health crises may inadvertently elevate MP exposure risks.

How can contamination be prevented during laboratory analysis of atmospheric samples for microplastics?

Microplastics (MPs) in the air and indoor environments are of growing concern and have led to increased testing for MPs. This study draws attention to the quality and quantitative measures of MP studies by conducting laboratory experiments (on solutions, filters, and blank samples) that were rarely or were not adopted in the airborne and indoor MP literature. Experiments have been conducted to identify contaminations that may come from experimental procedures while determining MPs in the air samples. MPs in different matrices during experiments were counted and categorized by their shapes. Chemical characterization was performed by Raman Spectroscopy. Results showed that laminar flow is the best option over a fume hood or standard laboratory environment for detecting air MPs to reduce blank levels. Blue-green and Black-Grey were the dominant colors; fiber was the predominant type of MPs seen, and most of them fall under the size range from (1-1000 µm) in different indoor environments and blanks. Common MPs seen were PP, PVA, PTFE, PVC, and HDPE. Thermal treatment of fresh unused filters at 450 °C for 4 h was effective as it reduced the MP count by 50%. Working solutions are mainly contaminated, and their pre-filtration is essential. The average deposition of MPs in blank samples during seven days was around 55 MPs. There is an urgent need for studies on developing quality control and quality assurance of airborne and indoor MPs. Hence, a standard protocol needs to be accepted; by harmonizing procedures, comparable results can be found, uncovering the correct levels of MP contamination, as required for risk assessment.

Indoor microplastics: a comprehensive review and bibliometric analysis

Indoor microplastic (MP) pollution is becoming a worldwide issue because people spend more time inside. Through dust and air, indoor MP pollution may harm human health. This review summarizes recent advancements in indoor MP research, covering pretreatments, quality control, filter membranes, and identification methods. Additionally, it conducts bibliometric analysis to examine the usage of keywords, publication records, and authors' contributions to the field. Comparatively, dust and deposition samples exhibit higher MP concentrations than indoor air samples. Fiber-shaped MPs are commonly detected indoors. The color and types of MPs display variability, with polypropylene, polyethylene, polyethylene terephthalate, and polystyrene identified as the dominant MPs. Indoor environments generally demonstrate higher concentrations of MPs than outdoor environments, and MPs in the lower size range (1-100 µm) are typically more abundant. Among the reviewed articles, 45.24% conducted pretreatment on their samples, while 16.67% did not undergo any pretreatment. The predominant filter utilized in most studies was the Whatman Glass microfiber filter (41.67%), and MPs were predominantly characterized using µ-FTIR (19.23%). In the literature, 17 papers used blank samples, and eight did not. Blank findings were not included in most research (23 articles). A significant increase in published articles has been observed since 2020, with an annual growth rate exceeding 10%. The keyword microplastics had the highest frequency, followed by fibers. This indoor MP study emphasizes the need for collaborative research, policymaking, and stakeholder involvement to reduce indoor MP pollution. As indoor MP research grows, so are opportunities to identify and minimize environmental and health impacts.

A systematic review of the impacts of exposure to micro- and nano-plastics on human tissue accumulation and health

Micro- and nano-plastics (MNPs) pollution has become a pressing global environmental issue, with growing concerns regarding its impact on human health. However, evidence on the effects of MNPs on human health remains limited. This paper reviews the three routes of human exposure to MNPs, which include ingestion, inhalation, and dermal contact. It further discusses the potential routes of translocation of MNPs in human lungs, intestines, and skin, analyses the potential impact of MNPs on the homeostasis of human organ systems, and provides an outlook on future research priorities for MNPs in human health. There is growing evidence that MNPs are present in human tissues or fluids. Lab studies, including in vivo animal models and in vitro human-derived cell cultures, revealed that MNPs exposure could negatively affect human health. MNPs exposure could cause oxidative stress, cytotoxicity, disruption of internal barriers like the intestinal, the air-blood and the placental barrier, tissue damage, as well as immune homeostasis imbalance, endocrine disruption, and reproductive and developmental toxicity. Limitedly available epidemiological studies suggest that disorders like lung nodules, asthma, and blood thrombus might be caused or exacerbated by MNPs exposure. However, direct evidence for the effects of MNPs on human health is still scarce, and future research in this area is needed to provide quantitative support for assessing the risk of MNPs to human health.

Microplastics in the Lung Tissues Associated with Blood Test Index

Microplastics (MPs) have received a lot of attention and have been detected in multiple environmental matrices as a new environmental hazard, but studies on human internal exposure to MPs are limited. Here, we collected lung tissue samples from 12 nonsmoking patients to evaluate the characteristics of MPs in human lung tissues using an Agilent 8700 laser infrared imaging spectrometer and scanning electron microscopy. We detected 108 MPs covering 12 types in the lung tissue samples, with a median concentration of 2.19 particles/g. Most of the MPs (88.89%) were sized between 20 to 100 μm. Polypropylene accounts for 34.26% of the MPs in the lung tissues, followed by polyethylene terephthalate (21.30%) and polystyrene (8.33%). Compared with males and those living far from a major road (≥300 m), females and those living near the main road (<300 m) had higher levels of MPs in lung tissues, which positively correlated with platelet (PLT), thrombocytocrit, fibrinogen (FIB), and negatively related with direct bilirubin (DB). These findings help confirm the presence in the respiratory system and suggest the potential sources and health effects of inhaled MPs.

Microplastics exposure and immunologic response

OBJECTIVE

To assess the impact of microplastics (MPs) on human health.

DATA SOURCE

The authors conducted a non-systematic review of articles published in English, Portuguese, French, and Spanish in the last decade in the following databases: PubMed, Google Scholar, EMBASE, and SciELO. The keywords used were: microplastics OR nanoplastics OR marine litter OR toxicology OR additives AND human health OR children OR adults.

DATA SUMMARY

MPs are a group of emerging contaminants that have attracted scientific interest and societal attention in the last decade due to their ubiquitous detection in all environments. Humans can primarily be exposed to MPs and nanoplastics via oral and inhalation routes, but dermal contact cannot be overlooked, especially in young children. The possible toxic effects of plastic particles are due to their potential toxicity, often combined with that of leachable additives and adsorbed contaminants.

CONCLUSIONS

Unless the plastic value chain is transformed over the next two decades, the risks to species, marine ecosystems, climate, health, economy, and communities will be unmanageable. However, along with these risks are the unique opportunities to help transition to a more sustainable world.

Plastics and Micro/Nano-Plastics (MNPs) in the Environment: Occurrence, Impact, and Toxicity

Plastics, due to their varied properties, find use in different sectors such as agriculture, packaging, pharmaceuticals, textiles, and construction, to mention a few. Excessive use of plastics results in a lot of plastic waste buildup. Poorly managed plastic waste (as shown by heaps of plastic waste on dumpsites, in free spaces, along roads, and in marine systems) and the plastic in landfills, are just a fraction of the plastic waste in the environment. A complete picture should include the micro and nano-plastics (MNPs) in the hydrosphere, biosphere, lithosphere, and atmosphere, as the current extreme weather conditions (which are effects of climate change), wear and tear, and other factors promote MNP formation. MNPs pose a threat to the environment more than their pristine counterparts. This review highlights the entry and occurrence of primary and secondary MNPs in the soil, water and air, together with their aging. Furthermore, the uptake and internalization, by plants, animals, and humans are discussed, together with their toxicity effects. Finally, the future perspective and conclusion are given. The material utilized in this work was acquired from published articles and the internet using keywords such as plastic waste, degradation, microplastic, aging, internalization, and toxicity.

Nasal lavage technique reveals regular inhalation exposure of microplastics, not associated from face mask use

During the COVID-19 pandemic, the use of face masks has been a worldwide primary protection measure to contain the spread of the virus. However, very little information is known about the possible inhalation of microplastics (MP) from wearing masks. This pilot study evaluates the presence of MP accumulated in nasal cavities through the nasal lavages technique. Six different commercial face masks were tested in 18 participants during five working days (8 h use/day). Eight different polymers (polystyrene, polyamide, poly(ethylene - propylene) diene monomer, polyester, polyethylene, polyvinylidene fluoride, polypropylene, and polyvinyl chloride) predominantly within the 20-300 µm size were detected in nasal lavages, with an average concentration of 28.3 ± 15.6 MP/5 mL nasal solution. Results demonstrate that MP in the nasal cavity are not associated to face mask use but rather to general exposure to airborne MP. We highlight the use of nasal lavages to evaluate human inhalation of MP and associate it to potential sources and risks.

Characterization of airborne microplastics at different workplaces of the poly(ethylene:propylene:diene) (EPDM) rubber industry

Microplastics (MPs) as an emerging air pollutant have received widespread attention, but research on airborne MPs at occupational sites is still limited, especially in the rubber industry. Hence, indoor air samples were collected from three production workshops and an office of a rubber factory producing automotive parts to analyze the characteristics of airborne MPs in different workplaces of this industry. We found MP contamination in all air samples from the rubber industry, and the airborne MPs at all sites mainly showed small-sized (< 100 μm) and fragmented characteristics. The abundance and source of MPs at various locations is primarily related to the manufacturing process and raw materials of the workshop. The abundance of MPs in the air was higher in workplaces where production activities are involved than in office (360 ± 61 n/m³), of which the highest abundance of airborne MPs was in the post-processing workshop (559 ± 184 n/m³). In terms of types, a total of 40 polymer types were identified. The post-processing workshop has the largest proportion of injection-molded plastic ABS, the extrusion workshop has a greater proportion of EPDM rubber than the other locations, and the refining workshop has more MPs used as adhesives, such as aromatic hydrocarbon resin (AHCR).

There's something in the air: A review of sources, prevalence and behaviour of microplastics in the atmosphere

Literature regarding microplastics in the atmosphere has advanced in recent years. However, studies have been undertaken in isolation with minimal collaboration and exploration of the relationships between air, deposition and dust. This review collates concentrations (particle count and mass-based), shape, size and polymetric characteristics for microplastics in ambient air (m3), deposition (m2/day), dust (microplastics/g) and snow (microplastics/L) from 124 peer-reviewed articles to provide a holistic overview and analysis of our current knowledge. In summary, ambient air featured concentrations between <1 to >1000 microplastics/m³ (outdoor) and <1 microplastic/m³ to 1583 ± 1181 (mean) microplastics/m³ (indoor), consisting of polyethylene terephthalate, polyethylene, polypropylene. No difference (p > 0.05) was observed between indoor and outdoor concentrations or the minimum size of microplastics (p > 0.5). Maximum microplastic sizes were larger indoors (p < 0.05). Deposition concentrations ranged between 0.5 and 1357 microplastics/m²/day (outdoor) and 475 to 19,600 microplastics/m²/day (indoor), including polyethylene, polystyrene, polypropylene, polyethylene terephthalate. Concentrations varied between indoor and outdoor deposition (p < 0.05), being more abundant indoors, potentially closer to sources/sinks. No difference was observed between the minimum or maximum reported microplastic sizes within indoor and outdoor deposition (p > 0.05). Road dust concentrations varied between 2 ± 2 and 477 microplastics/g (mean), consisting of polyvinyl chloride, polyethylene, polypropylene. Mean outdoor dust concentrations ranged from <1 microplastic/g (remote desert) to between 18 and 225 microplastics/g, comprised of polyethylene terephthalate, polyamide, polypropylene. Snow concentrations varied between 0.1 and 30,000 microplastics/L, containing polyethylene, polyamide, polypropylene. Concentrations within indoor dust varied between 10 and 67,000 microplastics/g, including polyethylene terephthalate, polyethylene, polypropylene. No difference was observed between indoor and outdoor concentrations (microplastics/g) or maximum size (p > 0.05). The minimum size of microplastics were smaller within outdoor dust (p > 0.05). Although comparability is hindered by differing sampling methods, analytical techniques, polymers investigated, spectral libraries and inconsistent terminology, this review provides a synopsis of knowledge to date regarding atmospheric microplastics.

Sampling strategies and analytical techniques for assessment of airborne micro and nano plastics

The atmosphere is pervasively polluted by microplastics and nano plastics (M/NPs) released into indoor and outdoor areas. However, various methodologies and their limitations along with non-standardization make the comparison of information concerning their prevalence difficult. Such diversity in techniques greatly limits the interpretation of results. Herein, We extracted data from publications on PubMed and Embase database up to the year 2022 regarding sampling strategies, identification methods, and reporting data for M/NPs quantification. In this review, 5 major areas for measuring airborne M/NPs have been identified including pre-sampling/ sampling/ post-sampling/ analysis/ and contamination avoidance. There are many challenges specific to each of those sections that need to be resolved through further method development and harmonization. This review mainly focuses on the different methods for collecting atmospheric M/NPs and also the analytical tools which have been used for their identification. While passive sampling is the most user-friendly method, the most precise and reproducible approach for collecting plastic particles is an active method which is directly followed by visual counting as the most common physical analysis technique. Polymers collected using visual sorting are most frequently identified by spectroscopy (FTIR; Raman). However, destructive analytical techniques (thermal degradation) also provide precise chemical information. In all cases, the methods were screened for advantages, limitations, and fieldwork abilities. This review outlines and critiques knowledge gaps, and recommendations to support standardized and comparable future research.

Atmospheric microplastics: exposure, toxicity, and detrimental health effects

Microplastics (MPs) are micro-particulate pollutants present in all environments whose ubiquity leads humans to unavoidable exposure. Due to low density, MPs also accumulate in the atmosphere, where they are easily transported worldwide and come into direct contact with the human body by inhalation or ingestion, causing detrimental health effects. This literature review presents the sources of atmospheric MPs pollution, transport routes, physicochemical characteristics, and environmental interactions. The document also explains the implications for human health and analyzes the risk of exposure based on the potential toxicity and the concentration in the atmosphere. MPs' toxicity lies in their physical characteristics, chemical composition, environmental interactions, and degree of aging. The abundance and concentration of these microparticles are associated with nearby production sources and their displacement in the atmosphere. The above elements are presented in an integrated way to facilitate a better understanding of the associated risk. The investigation results encourage the development of future research that delves into the health implications of exposure to airborne MPs and raises awareness of the risks of current plastic pollution to promote the establishment of relevant mitigation policies and procedures.

Exponential decrease of airborne microplastics: From megacity to open ocean

Atmospheric transport has been recognized as an important route for microplastics (MPs) entering the ocean since the early 2019s, yet little data of their distribution patterns in marine air are currently available. In this study, we conducted continuous measurements of atmospheric MPs in the marine boundary layer across the western Pacific Ocean. Results suggested that synthetic MPs comprised 25.89 % of all identified particles, with the most being cotton and cellulose (51.68 %). Research revealed that atmospheric synthetic microfibers (22.54 %) are higher than the proportion of the surface oceanic synthetic microfibers (8.20 %) in the recent study. Further, the size of airborne MP fibers over open ocean is probably not the limiting factor during long-range transport. The mean abundance of atmospheric MPs over the western Pacific Ocean during sampling period was 0.841 ± 0.698 items/100 m³. Regression analysis revealed an exponential relationship between average MP abundance and average longitude of sampled stations, and the average abundance of airborne MPs in coastal megacity is three orders of magnitude higher than that in sampled marine air of western Pacific. This study provides a better understanding on the impact of atmospheric transport of MPs within the global plastic cycle.

Microplastics and their Additives in the Indoor Environment

Analyses of air and house dust have shown that pollution of the indoor environment with microplastics could pose a fundamental hygienic problem. Indoor microplastics can result from abrasion, microplastic beads are frequently added to household products and microplastic granules can be found in artificial turf for sports activities and in synthetic admixtures in equestrian hall litter. In this context, the question arose as to what extent particulate emissions of thermoplastic materials from 3D printing should be at least partially classified as microplastics or nanoplastics. The discussion about textiles as a possible source of indoor microplastics has also been intensified. This Minireview gives an overview of the current exposure of residents to microplastics. Trends can be identified from the results and preventive measures can be derived if necessary. It is recommended that microplastics and their additives be given greater consideration in indoor environmental surveys in the future.

The Pressing Issue of Micro- and Nanoplastic Contamination: Profiling the Reproductive Alterations Mediated by Oxidative Stress

Micro- and nanoplastics (MPs/NPs) are among the most widely distributed pollutants in the environment. It has been suggested that exposure to MPs/NPs can trigger toxicity pathways among which inflammation and oxidative stress (OS) play a pivotal role. Once absorbed, MPs/NPs may act locally or access the bloodstream and, following the translocation process, reach several organs and tissues, including the gonads. Notably, MPs/NPs can bioaccumulate in human and murine placenta, opening new scenarios for toxicological evaluations. We review recent studies on the effects of MPs/NPs on the reproductive health in aquatic and terrestrial organisms of both sexes, focusing on the role of OS and the antioxidant defence system failure as the main underlying mechanisms. Alterations in gametogenesis, embryonic and offspring development, and survival have been shown in most studies and often related to a broken redox balance. All these detrimental effects are inversely related to particle size, whereas they are closely linked to shape, plastic polymer type, superficial functionalization, concentration, and time of exposure. To date, the studies provide insights into the health impacts, but no conclusions can be drawn for reproduction toxicity. The main implication of the few studies on antioxidant substances reveals their potential role in mitigating MP-induced toxic effects.

Applying Existing Particle Paradigms to Inhaled Microplastic Particles

Ambient particulate pollution originating from plastic contaminates air, including indoor and urban environments. The recent discovery of ambient microplastic (MP) particles of a size capable of depositing in the thoracic region of the airway, if inhaled, has raised concern for public exposure and health impacts following lessons learned from other particle domains. Current microplastic exposure estimates are relatively low compared to total ambient particulate matter, but optimal analytical techniques and therefore data for risk and health impact assessments are lacking. In the absence of such an evidence base, this paper explores paradigms, metrics and dose-response curves developed in other particle domains as a starting point for predicting whether microplastic are of concern. Bio-persistence, presence of reactive sites and soluble toxicants are likely key properties in microplastic toxicity, but these are not measured in environmental studies and hence are challenging to interpret in exposure. Data from a MP inhalation study in rats is available but the study was conducted using conditions that do not replicate the known human health effects of PM_2.5 or surrogate exposures: compromised, aged animal models are recommended to investigate potential parallels between MPs and PM_2.5. One of these parallels is provided by tire wear particles (TWP), which form part of current ambient PM and are sometimes regarded as microplastic. A connection to epidemiological studies where PM filters are still available is recommended and consequently analytical advances are required. In summary, established particle domains and existing paradigms provide valuable insight and data that can be used to predict MP toxicity, and direct study design and key properties to consider in this emerging field.