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Microplastics (MPs), as an entirely anthropogenic type of pollution, are considered to be stratigraphic markers of the Anthropocene Epoch, and have become of increasing public concern over the past decade. Recent studies have revealed that the atmosphere is an efficient medium to disseminate MPs from their sources to remote mountains and marine areas. However, current research on atmospheric MPs (i.e. airborne MPs) is generally less highlighted than MP water and soil pollution studies due to the lack of standard methods for the identification and quantification of atmospheric MPs. This paper reviews the published literature on airborne MPs, gives an overview of the advantages and disadvantages of current airborne MPs collection techniques, extraction methods and identification (i.e., ‘passive’ and ‘active’ sampling, density separation and visual identification), and lays a foundation for future studies. The physical and chemical characteristics, classification, spatial and temporal scale distributions, sources, transport, and environmental impacts of airborne MPs are summarized. There are substantial research gaps in the quantification of airborne MPs and the exploration of toxicity mechanisms of inhalable MPs. The establishment of accredited methods is an urgent challenge for a better understanding on airborne MPs and their environmental and health effects. As one of the constituents in many aerosols, airborne MPs should be treated as a recognized pollutant for long-term monitoring, and the factors that specifically affect airborne MPs could be better addressed by means of the characterization of individual MPs. In the future, the effects and interaction of MPs in the atmosphere, lithosphere and hydrosphere are also of critical importance.

The rapid and reliable detection of bacteria plays an important role in clinical and veterinary practice. A stable, label free, compact, and sensitive long-period fiber grating (LPFG) sensor based on egg yolk antibody (IgY) was proposed for the detection of Staphylococcus aureus (S. aureus). LPFG was fabricated with laser writing technology, and specific IgY was further immobilized on the grating region and then combined with the corresponding bacteria. S. aureus was detected by tracking the change of resonance wavelength in the LPFG transmission spectrum caused by bacteria–antibody interaction induced by the increase of biological cover thickness and density after the immune reaction. The testing results showed that the proposed sensor was selective and sensitive to S. aureus measurement, and the detection limit is approximately 33 CFU/mL. The proposed antibody immobilization method is very simple, and the optical fiber can be manufactured in batch to reduce the cost. The detection time of the sensor is around 20 min, which is fast and suitable for detection. The assay was successfully applied for the quantitative analysis of S. aureus in natural waters and met the needs of on-site screening trace pathogenic bacteria in food safety control.

Air pollution is a major environmental health challenge in megacities, and as such a Comprehensive Action Plan (CAP) was issued in 2017 for Beijing, the capital city of China. Here we investigated the size-segregated airborne particles collected after the implementation of the CAP, intending to understand the change of oxidative potential and water-soluble heavy metal (WSHM) levels in 'haze' and 'non-haze' days. The DNA damage and the levels of WSHM were analyzed by Plasmid Scission Assay (PSA) and High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) techniques. The PM mass concentration was higher in the fine particle size (0.43-2.1 μm) during haze days, except for the samples affected by mineral dust. The particle-induced DNA damage caused by fine sized particles (0.43-2.1 μm) exceeded that caused by the coarse sized particles (4.7-10 μm). The DNA damage from haze day particles significantly exceeded those collected on non-haze days. Prior to the instigation of the CAP, the highest value of DNA damage decreased, and DNA damage was seen in the finer size (0.43-1.1 μm). The Pearson correlation coefficient between the concentrations of water-soluble Pb, Cr, Cd and Zn were positively correlated with DNA damage, suggesting that these WSHM had significant oxidative potential. The mass concentrations of water-soluble trace elements (WSTE) and individual heavy metals were enriched in the finer particles between 0.43 μm to 1.1 μm, implying that smaller sized particles posed higher health risks. In contrast, the significant reduction in the mass concentration of water-soluble Cd and Zn, and the decrease of the maximum and average values of DNA damage after the CAP, demonstrated its effectiveness in restricting coal-burning emissions. These results have demonstrated that the Beijing CAP policy has been successful in reducing the toxicity of 'respirable' ambient particles.

Beijing is one of the most important Chinese megacities with extremely serious air pollution problems and human \udhealth impacts. In response to the air pollution the central and municipal governments of China have implemented a series of actions; one of which is the “Action Plan for Comprehensive Prevention and Control of \udAutumn and Winter Air Pollution in Beijing-Tianjin-Hebei and Surrounding Areas 2017–2018” (the Action Plan) \udissued in 2017. The morphology, composition and mixing state of individual particles collected after the Action \udPlan was implemented were analyzed by high resolution-transmission electron microscopy coupled with an \udenergy-dispersive X-ray spectrometer (TEM-EDX). The relative percentages of different individual particle types \udand the main sources of the particulate pollution before and after the Action Plan were compared. The results \udshowed that sulfur was most frequently detected in the individual particles, and the particle types were mainly \udcomposed of soot aggregates, mineral particles, organic particles, metal particles, coal fly ashes, sulfate particles, \udand mixture particles. The mixture and sulfate particles dominated in the autumn samples, both for the haze and \udnon-haze days. In winter the mineral and mixture particles dominated in samples for the non-haze days, while \udmixture particles and sulfate dominated in the samples for the haze days. The mixture particles in autumn were \udmainly the soot aggregates internally mixed with sulfate (S-soot type), while the mixture particles in winter were \udmainly the S-soot type and the mineral particles internally mixed with sulfate (S-mineral type). After the Action \udPlan, the relative percentages of sulfate particles, organic particles, and soot aggregates increased, while the \udrelative percentages of mineral particles, metal particles and fly ashes decreased. The contribution from coal�fired sources was reduced significantly as evidenced by the decrease in the fly ash particles. The vehicle emis�sions and secondary reaction of particulate matter became the main sources of atmospheric particulate matters as \udevidenced by increase in sulfate particles, organic particles, and soot aggregates. The results presented in this \udstudy will assist in other plans to improve air quality and human health in megacities around the world.

Single image deblurring aims to restore the single blurry image to its sharp counterpart and remains an active topic of enduring interest. Recently, deep Convolutional Neural Network (CNN) based methods have achieved promising performance. However, two primary limitations mainly exist on those CNNs-based image deblurring methods: most of them simply focus on increasing the complexity of the network, and rarely make full use of features extracted by encoder. Meanwhile, most of the methods perform the deblurred image reconstruction immediately after the decoder, and the roles of the decoded features are always underestimated. To address these issues, we propose a single image deblurring method, in which two modules to fuse multiple features learned in encoder (the Cross-layer Feature Fusion (CFF) module) and manipulate the features after decoder (the Consecutive Attention Module (CAM)) are specially designed, respectively. The CFF module is to concatenate different layers of features from encoder to enhance rich structural information to decoder, and the CAM module is able to generate more important and correlated textures to the reconstructed sharp image. Besides, the ranking content loss is employed to further restore more realistic details in the deblurred images. Comprehensive experiments demonstrate that our proposed method can generate less blur and more textures in deblurred image on both synthetic datasets and real-world image examples.

Exploiting the full potential of copper-based nanoparticles in the activation of peroxymonopersulfate (PMS) is a great challenge due to their insufficient dispersity and electronic properties. We report here a novel iron‑nitrogen co-doped carbon nanotube (FNC) modified with a Cu2O nanocomposite (Cu2O/FNC) that exhibits ultrahigh catalytic performance in the activation of PMS to degrade fluconazole (~95%). Catalytic performance evaluation illustrated that Cu2O/FNC also has wide pH applicability (3.0-11.0), long-term stability and excellent adaptability. In addition, luminescent bacteria toxicity tests confirm that Cu2O/FNC/PMS significantly reduced the acute biotoxicity of various recalcitrant pollutants (reduced by 45-83%). By identifying the reactive oxygen species (ROS) and catalytic performance for various pollutants, we propose that pollutants that interact weekly with activators are mostly destroyed by sulfate radicals and hydroxyl radicals, whilst both radical and non-radical routes were involved in the degradation of pollutants that were easily adsorbed. By modifying Cu2O with FNC, several crucial properties such as the specific surface area, surface defects, active sites and the charge transfer rate were significantly improved, leading to excellent catalytic performance for pollutant removal. Finally, a reasonable reaction mechanism is advanced for the fluconazole degradation pathway. This study not only develops a novel PMS oxidation system for fluconazole degradation, but also provides a new strategy to improve the reactivity and applicability of PMS activators by combining radical and non-radical activation pathways.

Airborne fibers are of public concern because of their potential threat to the environment, however their physical and chemical properties are poorly understood. Fibers are defined as having an aspect ratio >3:1. Fiber particles were collected in the near surface air, surface deposited dust and building materials in Beijing. They were examined using analytical scanning electron microscopy. The particles were initially classified into two categories: organic and inorganic. Organic fibers comprised microplastic and natural organic fiber particles. Inorganic fibers were mainly man-made mineral fibers (MMMFs), asbestos (represented by chrysotile), calcium sulfate and metal fiber particles. Microplastic and MMMFs fibers were most abundant, accounting for 34.6% and 40.3% in total, respectively, followed by asbestos (7.8%), calcium sulfate (7.2%), metal fibers (5.6%) and natural organic fiber particles (4.5%). The number-concentration of these particles was about 16.7 × 10−3 fibers/ml at 1.5 m above the ground and about 14.1 × 10−3 fibers/ml at about 18 m, suggesting the particles were mainly derived from surface and were re-suspended. Approximately 80% of the airborne fiber were smaller than 20 μm in length, which is possibly the critical size for fiber particles to re-suspend into the air. Surface dust and construction sites were speculated to be the major contributors of the fiber particles.