Pollution characteristics and potential health effects of airborne microplastics and culturable microorganisms during urban haze in Harbin, China

A critical review of the ecotoxic effects of microplastics on aquatic, soil and atmospheric ecosystems and current research challenges

The extensive use of plastics has brought unparalleled convenience to human social development. However, this has also led to severe environmental and health challenges, with microplastic (MP) pollution emerging as one of the most pressing issues. As ubiquitous environmental pollutants, MPs persist in ecosystems and pose potential risks to both ecological and human health. Studies reveal that MPs impact aquatic, soil, and atmospheric ecosystems by altering their physicochemical properties and causing toxicological harm to resident organisms. Despite these findings, a comprehensive assessment and analysis of MP impacts, especially on atmospheric ecosystems, remains lacking. Similarly, the environmental biotoxicity mechanisms associated with MPs are yet to be systematically described. This review provides an in-depth discussion of the sources and characteristics of MPs, laying the background for elaborating their ecological effects. Current knowledge on MP ecotoxicity in aquatic, soil, and atmospheric ecosystems is then synthesized. Potential molecular mechanisms of biotoxicity are explored. Oxidative stress, inflammatory responses, and metabolic signaling pathway impairment are considered important pathways through which MPs induce toxic injury in environmental animals and have received widespread attention. Additionally, this review emphasizes the challenges faced in studying ecotoxic effects and mechanisms of MPs, such as the lack of reliable detection of environmental MPs and in-depth mining of relevant data, and suggests possible directions for future research. Although progress has been made, significant knowledge gaps remain. Addressing these gaps is critical if effective strategies are to be developed to reduce the environmental and health risks posed by MPs.

Air pollution and its impacts on health: Focus on microplastics and nanoplastics

Air pollution represents a significant public health concern, contributing to approximately 6.7 million premature deaths annually. Among the various pollutants, particulate matter (PM)2.5, emitted from fossil fuel combustion, poses a significant health risk. It induces oxidative stress and increases respiratory and cardiovascular disease risk. Recently, particulate plastics, classified as microplastics (MPs) (less than 5 mm) or nanoplastics (NPs) (less than 1 μm), have been identified as environmental contaminants. It has been demonstrated that plastic particles, including MPs and NPs, can gain access to the human body via inhalation, ingestion, and dermal contact, resulting in various adverse health effects, such as inflammation and oxidative stress. Particulate plastics have been identified in human biological samples, including blood, saphenous vein tissues and lung tissues. Moreover, their presence in PM2.5, particularly in urban settings, exacerbates the health risks associated with air pollution. This review addresses the sources, detection, health effects, and mitigation strategies for particulate plastics in the atmosphere. Additionally, the study discusses the biological degradation of particulate plastics by microorganisms and the potential of advanced oxidation processes for their removal. These comprehensive approaches could reduce the environment and human health from the adverse effects of airborne particulate plastics.

Aerosols Generated in the Wastewater Treatment Process Are a Potential Source of Airborne Microplastics

Airborne microplastics pose a significant risk to human health. Similarly to the water-air transfer process, such as sea spray, aerosols generated during the wastewater treatment process, driven by aeration and mechanical agitation, are an overlooked potential source of airborne microplastics. This study constitutes the first attempt to investigate the pollution characteristics of microplastics in aerosols generated during wastewater treatment, based on laser direct infrared spectroscopy (LDIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Microplastics were ubiquitously observed in aerosols from each unit of the wastewater treatment plant, with abundances in the range of 0.83-28.03 items·m-3. A total of 30 different polymer types were identified by LDIR, while polyvinyl chloride and polyethylene terephthalate were the most common polymers. Film and fragment were the main shapes, with a predominant size range of 20-50 μm. The aerosolization degree of microplastics is affected by the aeration intensities and hydrodynamic conditions maintained in each unit, but also varied depending on their inherent characteristics. These findings suggest that the aerosolization of microplastics from wastewater treatment is a potential source of airborne microplastics. This study contributes a novel insight into the occurrence of microplastics in aerosols generated during wastewater treatment.

Fine micro- and nanoplastics concentrations in particulate matter samples from the high alpine site Sonnblick, Austria

We report atmospheric fine micro- and nanoplastics concentrations from particulate matter (PM) samples of two size fractions (PM10, fine micro- and nanoplastics, and PM1, nanoplastics), which were collected at the remote high alpine station Sonnblick Observatory, Austria. Active sampling was performed from June 2021 until April 2022. Analysis was done using TD-PTR-MS to detect 6 different plastic types. Polyethylene terephthalate (PET), polyethylene (PE) and polypropylene/polypropylene carbonate (PP/PPC) were found to be the dominating species. PET was detected in almost all samples, while the other plastic types occurred more episodically. Furthermore, polyvinyl chloride (PVC), polystyrene (PS) and tire wear particles were detected in single samples. Considering the three main plastic types, average plastics concentrations were 35 and 21 ng m-³ with maximum concentrations of 165 and 113 ng m-³ for PM10 and PM1, respectively. Average polymer concentrations were higher in the summer/fall period than in winter/spring. In summer/fall, PM10 plastics concentrations were higher by a factor of 2 compared to PM1, while concentrations of both size classes were comparable in the winter/spring period. This suggests that in the colder season plastic particles arriving at the Eastern Alpine crests are mainly present as nanoplastics. The contribution of micro- and nanoplastics to organic matter at the remote site was found to be comparable to data determined at an urban site. We found significant correlations between the PET concentration and tracers originating from anthropogenic activities such as elemental carbon, nitrate, ammonium, and sulphate as well as organic carbon and arabitol.