AS3.10
Orals: Fri, 28 Apr | Room 0.51
The occurrence of micro and nano plastics has been reported in every environmental compartment including marine and freshwaters, soils and sediments, air and atmospheric precipitations. Recent evidence showing the presence of airborne microplastics in remote ecosystems highlights the extent of this pollution. The atmospheric transportation and the distribution of airborne microplastics still need to be better documented to understand the dynamic of microplastic transfer between ecosystems.
While most studies dedicated to the analysis of microplastics in the air use a passive sampling methodology through atmospheric deposition we developed an original stainless device to sample large volumes of air with high debit (2000 L/min) providing a fast sampling of aerosols within a small localized area. An optimized sampling protocol has been deployed in the North Western Mediterranean Sea from the Expedition 7th Continent (E7C) boat. 19 sampling sites have been studied during the E7C expedition in September-October 2019, including measurements in port and coastal areas as well as offshore environments. The analysis of micro/nano plastics was carried out using pyrolysis coupled with gas chromatography and tandem mass spectrometry (Py-GC-MS/MS). This approach allowed us to evaluate the concentrations of micro and nano plastics present in the samples for 5 types of plastics (polypropylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate and polycarbonate) and for 2 size ranges (5-50μm and <5μm).
This study confirmed that plastic particles are present in the atmosphere even in remote areas such as the offshore environments. The results showed that airborne micro and nano plastics were detected at each sampling station, from the coast to the open sea, at various concentrations. Py-GC-MS/MS analysis allowed us to quantify the 5 types of polymer and revealed the predominance of PET and PP material. High-volume samplers and Py-GC-MS/MS analysis have proven to be an efficient and powerful methodology to gather and quantify airborne plastic particles at micro and nanoscale level.
How to cite: Eyheraguibel, B., Ter Halle, A., Ourmieres, Y., Ghiglione, J.-F., and Amato, P.: High debit sampling of airborne micro and nanoplastics in remote sea, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6536, https://doi.org/10.5194/egusphere-egu23-6536, 2023.
Global Modeling of Microplastics in the Atmosphere
Shanye Yang, Guy Brasseur, Stacy Walters, Pablo Lichtig, Cathy Wing Yi Li, Xiaofei Wang
Global model simulations driven by bottom-up emissions show that more than 100 kilotons of microplastic particles are suspended in the atmosphere. The calculations are based on estimated emissions associated to traffic, agriculture, domestic activities and ocean exchanges. They make use of our laboratory measurements of microplastic exchanges at the water-air interface that is considerably less intensive than the emissions from land. Approximately 20 million tons are deposited each year on the Earth’s surface, and 3 million tons in the oceans. These model simulations show that the microplastic particle abundance is considerably higher over the continents, which is consistent with current observations. Exposure risks are highest in the most populated areas. Worldwide, adults inhale 2.4 × 107 - 1.5 × 109 microplastic particles per year. Remote areas including Antarctica and the Arctic are also important receptor regions for the particles with a diameter smaller than 1.5 μm.
How to cite: Yang, S.: Global Modeling of Microplastics in the Atmosphere, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13376, https://doi.org/10.5194/egusphere-egu23-13376, 2023.
Microplastic particles (MP), i.e., plastic particles with a size between 1 µm and 1 mm, have been detected in all compartments of the Earth system. While we are beginning to develop a quantitative understanding of the primary emissions of MPs such as tire wear, secondary sources from polluted environmental compartments such as the oceans and arid land surfaces, are currently not understood at all.
In this study, we use reported MP concentrations in soils across the world combined with MP enrichment ratios (ER) in wind eroded sediments with respect to the soils (Bullard et al., 2021; Rezaei et al., 2019; Tian et al., 2022) and a population density map to estimate MP resuspension factors (RF) from arid regions. We then use global, 3-hourly dust emissions at 0.5o x 0.5o resolution from FLEXDUST (Groot Zwaaftink et al., 2016, 2017), as a proxy for the spatial and temporal variation of MPs emitted by arid regions. Scaled with the resuspension factors, we estimate the global MP resuspensions. To calculate the uncertainty of our emission model, we conduct a one-thousand-member Monte Carlo simulation with 14 different RF scenarios for each population category, perturbing the MP concentration in soils, the ER and the spatial scale used for the population density.
We define, as a reference case, the emissions derived from the average ER, average soil concentrations and 50 km radius population categorization. These MP resuspension emissions are used as input to the Lagrangian atmospheric dispersion model FLEXPART (Pisso et al., 2019; Stohl et al., 2005) to simulate the global atmospheric cycle of resuspended MPs from arid regions. The simulations are driven by ERA5 meteorological fields at 0.5° horizontal resolution and 1-hour temporal resolution. We simulate the global atmospheric concentration and the deposition of resuspended MPs for different size distributions as well as shapes (spheres, fibers) of MPs. Lastly, we quantify the impact and compare it with observations, to estimate the importance of resuspension from arid regions for global MP abundance.
How to cite: Evangelou, I., Tatsii, D., Bucci, S., Groot Zwaaftink, C., and Stohl, A.: Resuspension of microplastic particles from arid regions and global impacts on atmospheric concentrations and deposition, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-662, https://doi.org/10.5194/egusphere-egu23-662, 2023.
While microplastics (MP) have been recently identified and recognized as a pollutant for the atmospheric environment, little is known about their actual emissions and concentration in the atmosphere. In this work, we follow a bottom-up approach to estimate the fluxes of MP at the ocean-atmosphere interface.
Coupling a sea spray emission scheme (Grythe et al. 2014) with the MP concentrations over the ocean surface simulated by the NEMO-PISCES general circulation model (Nucleus for European Modelling of the Ocean, Pelagic Interaction Scheme for Carbon and Ecosystem Studies, Richon et al. 2022), we estimate the global sea spray MP emissions at 6-hourly resolution, over a one-year period.
The MP emission fluxes are then fed into the Lagrangian atmospheric dispersion model FLEXPART (Stohl et al., 2005; Pisso et al., 2019), driven with hourly ERA5 data at 0.5° horizontal resolution, to provide a global picture of the atmospheric cycle of the MP of marine origin.
We discuss the main emission areas and their marked seasonal variability, the resulting atmospheric concentration across the globe and the deposition fluxes on both land and ocean surfaces. Finally, we compare simulated fluxes and concentrations with existing observations of MP in the marine atmosphere.
How to cite: Bucci, S., Richon, C., Bakels, L., and Stohl, A.: Global microplastic emission and deposition fluxes at the ocean-atmosphere interface, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9154, https://doi.org/10.5194/egusphere-egu23-9154, 2023.
In recent years, microplastic transport through the atmosphere has gained interest. This pathway allows microplastics to reach remote regions of the world and draws attention to the impact which they may have on global climate processes and human health. Remote regions, particularly in the Southern Hemisphere, are currently under-researched and the understanding of airborne microplastics still in its infancy. Atmospheric deposition and seawater samples were collected on board a RV Tangaroa voyage, which sailed from Wellington, New Zealand to the Ross Sea, Antarctica in January 2021. Marine and atmospheric microplastics were collected and analysed spectroscopically to confirm polymer composition. The findings from this study will be discussed, highlighting the ubiquitous nature of microplastics throughout the Southern Ocean. This study contributes a unique data set from a remote region of the world, and further develops our understanding of marine-atmosphere fluxes of microplastics.
How to cite: Aves, A., Livingstone, E., Law, C., Revell, L., and Gaw, S.: Airborne and marine microplastics in the Southern Ocean environment, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-589, https://doi.org/10.5194/egusphere-egu23-589, 2023.
Abstract:
Atmospheric transportation can be an essential pathway for microplastics (MPs), yet the understanding of the abundance, composition and morphological characteristics of the air-transported MPs remain limited.
In this study, we sampled freshly fallen snow at six locations around Riga in Latvia, covering land uses of urban, rural, and remote regions (Figure 1): i) Central market (CM) at Riga Central Market, ii) Old town (OT) at Doma Church Square, iii) Parking lot (PL) at Spice Home Parking, iv) Suburb (SB) at Pavasara str. 4, v) City roof (CR) at about 50 m high on Latvian Academy of Science building and vi) Gauja National Park (NP). Samples were collected 8 – 9 December 2021. 20 L stainless steel buckets and a metal shovel were used to collect the samples. To minimize contamination, plastic tools were avoided except rubber boots and gloves. The collected snow was taken to the laboratory and kept at room temperature (22 – 23°C) until it melted. After measuring the volume of the melted snow, it was filtered through 10 µm mesh stainless steel filters. MPs were extracted from the collected particles through enzyme treatment, oxidation, and density separation (Chand et al., 2021; Simon et al., 2018). The extracted particles were analysed by FPA-µFTIR imaging, and the obtained hyperspectral images were analysed by siMPle for MP identification. Laboratory processes were conducted in a clean fume hood and only cotton lab coats were worn in the lab.
MPs were detected in all snow samples, covering 16 polymer types. The most common polymers were polyester, polypropylene (PP), polyvinyl chloride (PVC), polyethylene (PE), and polyamide (PA). The results showed a large variation in MP concentration between the sites (Figure 1), among which Central market had the highest MP accumulation with 2497±755 items L-1, followed by Parking (1278±394 items L-1) and Old town (1233±57 items L-1). The order was the same when quantifying MP mass. Though also located in the urban area, snow on the City roof had significantly fewer MPs (95±19 items L-1) than other urban snow samples. This indicates that the snow had collected much of its MP while falling the last few meters or while lying on the ground. The least contaminated snow was found in Gauja National Park, which is remote from the urban area.This concludes that the MP snow contamination closely depends upon the human activities as well as strongly affected by the local sources.
Figure 1: MP particle concentration (above) and MP mass concentration (below) in the analysed samples from different sampling locations
References
Chand, R., Rasmussen, L.A., Tumlin, S., Vollertsen, J., 2021. The occurrence and fate of microplastics in a mesophilic anaerobic digester receiving sewage sludge, grease, and fatty slurries. https://doi.org/10.1016/j.scitotenv.2021.149287
Simon, M., van Alst, N., Vollertsen, J., 2018. Quantification of microplastic mass and removal rates at wastewater treatment plants applying Focal Plane Array (FPA)-based Fourier Transform Infrared (FT-IR) imaging. Water Res. 142, 1–9. https://doi.org/10.1016/j.watres.2018.05.019
How to cite: Chand, R., Liu, F., Haaning Nielsen, A., Putna -Nīmane, I., Vecmane, E., and Vollertsen, J.: Freshly fallen snow with full of microplastics: A scientific research in Riga central and peripheral area, Latvia., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8026, https://doi.org/10.5194/egusphere-egu23-8026, 2023.
The steady high demand for plastics and the degradation of discarded materials have led to microplastics and nanoplastics becoming important pollutants in various environmental compartments. While the situation, e.g. in the marine environment, is frequently described in the literature, a focused research on ambient air and especially different size classes of airborne particulate matter is scarce. Still, airborne particles are of special importance, as they have high mobility and can be transported and distributed rapidly.
We analysed particulate matter samples of two size classes, PM1 and PM10 (particles with aerodynamic diameters up to 1 or 10 µm, respectively), using thermal desorption-proton transfer reaction-mass spectrometry (TD-PTR-MS) and determined and quantified different polymer types from the spectra using a previously described method [1]. Particulate matter was collected at the remote high alpine Global Atmosphere Watch station Sonnblick Observatory, Austria, at more than 3100 m above sea level on quartz-fibre filters. Sampling time was one week. The samples covered a summer period (June 2021 to September 2021) and a winter period (December 2021 to April 2022). The periods were selected to include samples with and without mineral dust occurrence to allow a comparison. For the 23 samples of PM1 and PM10, analysis was done in triplicates. Field blanks were also available. Several lab and field tests were performed to check possible influences during the storage of samples (use of different containers including plastics and aluminium foil) and sample preparation (addition of hydrogen peroxide).
Our evaluations include the determination of six common types of plastics (PET, PE, PP/PPC, PS, PVC, tire wear) in both fractions and seasonal differences in their relative contributions. The most abundant plastic types were PET, PE and PP/PPC. Overall polymer concentrations reached up to 125 ng/m³. Field blanks showed comparably low presence of PET. We further compare the relative contributions of the summer and winter periods depending on the occurrence of mineral dust.
[1] Materić, D. et al., Micro- and Nanoplastics in Alpine Snow: A New Method for Chemical Identification and (Semi)Quantification in the Nanogram Range. Environmental science & technology 2020, 54(4), 2353-2359.
How to cite: Kau, D., Materić, D., Holzinger, R., and Kasper-Giebl, A.: Fine microplastics and nanoplastics in particulate matter samples from a high alpine environment, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5730, https://doi.org/10.5194/egusphere-egu23-5730, 2023.
The continued increase in global plastic production and poor waste management ensures that plastic pollution is a serious environmental concern for years to come. Because of their size, shape, and relatively low density, primary or secondary plastic particles in the environment between 1-1000 µm in size (known as microplastics, or MPs) may be entrained (and/or re-entrained) into the atmosphere through processes similar to other coarse-mode particles, such as mineral dust. MPs can thus be advected over great distances, reaching even the most pristine and remote areas of the Earth, and may have significant negative consequences for humans and the environment. The detection and analysis of MPs once airborne, however, remains a challenge because most observational methods are offline and resource-intensive, and, therefore, are not capable of providing continuous quantitative information.
In this study, we present results using an online, in situ airflow cytometer (SwisensPoleno Jupiter; Swisens AG; Horw, Switzerland) – coupled with machine learning – to detect, analyze, and classify airborne, single-particle MPs in near real time. The performance of the instrument to differentiate single-particle MPs of five common polymer types was investigated under laboratory conditions using combined information about their size and shape (determined using holographic imaging) and intrinsic fluorescence, known as autofluorescence, measured using three excitation wavelengths and five emission detection windows. The classification capability using these methods was determined alongside other coarse-mode aerosol with similar morphology or autofluorescence characteristics, such as a mineral dust and several pollen taxa.
The tested MPs exhibit a measurable autofluorescence signal that not only allows them to be distinguished from the other particles in this study demonstrating autofluorescence properties, such as pollen, but can also be differentiated from each other, with high (>90%) classification accuracy based on their multispectral autofluorescence signatures and morphology. The results using the presented novel methods are expected to provide a foundation towards significantly improving the understanding of properties and types of MPs present in the atmosphere.
How to cite: Beres, N., Burkart, J., Graf, E., Zeder, Y., Niederberger, E., Dailey, L. A., and Weinzierl, B.: A novel online method for the detection, analysis, and classification of airborne microplastics, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12884, https://doi.org/10.5194/egusphere-egu23-12884, 2023.
Since the Covid-19 pandemic, 129 billion masks have been consumed each month worldwide. Fate of masks not only include waste disposal sites and natural environments, but masks made from synthetic fibers may release micro(nano)plastics (MNPLs) that may reach respiratory tracts. However, degradation rate of MNPLs generated from masks have been unknown.
Here, we simulated the photolysis of surgical masks made from polypropylene equivalent to 900 days. Size-fractionated MNPL formation was quantified using vibrational spectroscopic imaging, and mask deformation and morphology were characterized with correlative microscopy. Three layers of masks did not exhibit signs of degradation from hydroxyl and carbonyl groups, however, the outer layer exhibited a linear increase in crystallinity calculated from the peak height of two characteristic bands, indicating that degradation started from amorphous regions. However, for microplastics > 10 μm, both groups were observed, and mass concentration was 10 mg/item calculated from FTIR imaging data. Fine microplastics <10 μm were imaged and fitted as ellipses, and the most abundant aspect ratio was 2. Nanoplastics (<1 μm) with an average size of 149 (59) nm were detected by SEM/STEM and Raman spectroscopy. Cluster analyses on spectra categorized three groups, suggesting different additives (e.g., dyes) were added. This study detected nanoplastics from degraded masks, which have major implications for their environmental fate and human health effects.
How to cite: Peng, G., Materic, D., and Reemtsma, T.: Detection and Quantification of Micro(nano)plastics Release from Photolysis of Surgical Masks, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4226, https://doi.org/10.5194/egusphere-egu23-4226, 2023.
Microplastics (MPs) are nowadays observed in all environmental compartments. However, in the atmosphere, the presence of this new pollutant is not well documented and not well understood. So far, atmospheric microplastic particles have been observed in megacities,1 in remote mountain areas2 and even over the open ocean,3 albeit in low concentrations. Microplastics exposed to the atmosphere, undergo ageing under the influence of atmospheric oxidants and sunlight. As the MPs are altered over time, their physicochemical properties are modified. In particular, the polymer structure of MPs can become more porous increasing their exposed surface compared to their new counterparts. This in turn can lead to an increased reactivity between atmospheric oxidants / pollutants and polymers. Furthermore, their physicochemical changes can ultimately lead to fragmentation, giving rise to the formation of more and smaller particles. It therefore seems important to quantify the reactivity of these new pollutants with atmospheric oxidants, as this can affect the role of MPs in the atmosphere, and their environmental fate. The present study provides the first results of a laboratory study on the reactivity of model microplastics, PEEK, PTFE, LDPE, PET, with ozone in a in a DRIFT (Diffuse Reflectance Infrared Fourier Transform) optical cell for the in-situ monitoring of MPs surface aging, coupled with an ozone analyser and a soft ionization Mass spectrometer (SIFT-MS), for the real-time monitoring of the gas-phase. The in-situ monitoring of MPs properties with DRIFTs revealed important chemical changes on their surface due to their exposition to ozone. We suggest that carboxylic acids and/or esters are amongst the most prominent reaction products. We also determine the ozone uptake coefficient (γss) of the MPs, and the evolution of their specific surface area before and after exposure to ozone. The values of γss measured are in the range of 10-8 to 10-9, indicating that MPs are not an important sink of gaseous O3 in the atmosphere. Further analysis of the gas-phase with SIFT-MS, evidenced the formation of VOCs and particularly carboxylic acids amongst the most prominent reaction products of MPs reaction with ozone. The impact of the modification of chemical functionalities at the surface of these microplastic on their environmental behaviour (e.g. hygroscopicity) and the reactivity of microplastics on the composition of the atmosphere is further discussed.
Ref. : [1] Dris et al., 2015, Environ. Chem / [2] Allen et al., 2015, Nat. Geosci. / [3] Trainic et al., 2020, Commun. Earth Environ.
How to cite: Tinel, L., Remoissenet, E., Constant, M., Allary, C., and Romanias, M.: Reactivity of selected model microplastics with ozone, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-17295, https://doi.org/10.5194/egusphere-egu23-17295, 2023.
Posters on site: Fri, 28 Apr, 08:30–10:15 | Hall X5
In recent years airborne microplastics have emerged as a ubiquitous pollutant worldwide, with negative implications for ecosystems, climate and human health. The differing sampling and analysis techniques used amongst micro- and nanoplastic research groups limits our understanding of the global distribution of airborne microplastics and nanoplastics. We present plans and progress for an ongoing coordinated inter-laboratory experiment, designed to elucidate strengths and weaknesses of individual analysis methods. Daily active pumped air samples were collected in a controlled manner at a remote site in Canterbury, New Zealand, alongside weekly deposition samples. All samples were divided evenly, using specific contamination controls, into four sample sets for interlaboratory method comparisons, and distributed to participating research groups in New Zealand, Germany and the UK. Samples will be analysed using common microplastic analysis techniques: micro-Fourier transform infrared spectroscopy (µFTIR), micro-Raman spectroscopy (µRaman), fluorescence microscopy, pyrolysis – gas chromatography/mass spectrometry (Py-GC/MS), and thermal desorption – proton transfer reaction – mass spectrometry (TD-PTR-MS). The results will allow quantification of the relative uncertainties and biases associated with each individual method, and inform how future airborne microplastics studies performed with different analytical methods should be interpreted.
How to cite: Revell, L., Aves, A., MacDonald, A., Allen, D., Allen, S., Materic, D., Gaw, S., Davy, P., and Naeher, S.: Quantifying the uncertainty and errors between common analytical methods for measuring airborne microplastics, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1144, https://doi.org/10.5194/egusphere-egu23-1144, 2023.
Nano- and microplastics (NMP), including tire wear particles (TWP), are now a global concern in the terrestrial and marine environment and are subject of intense study. The existence of NMP and TWP in many different environments has been reported, including soil, sediment, dust, glaciers, lakes, rivers, seas, and oceans. However, only a few studies have examined the abundance and fate of synthetic polymers in ambient aerosol particles. The dispersion, atmospheric transport and deposition of NMP and TWP are important steps in the biogeochemical cycle of plastic. The inconsistencies in the methods of sampling, processing, analysis, and the Quality Assurance (QA)/ Quality Control (QC) procedures of NMP and TWP hinder our ability to examine these contaminants' spatial and temporal patterns in the atmosphere. Based on the previously reported research on the analysis of NMP and TWP in the air, it becomes necessary to develop a comprehensive standard methodology that should be established for detecting microplastics in the atmosphere at submicron level (PM10 and PM2.5). Since synthetic polymers are difficult to quantify at low concentrations, Pyrolysis-Gas Chromatography coupled with Mass Spectrometry provides an effective technique for detecting NMP and TWP. As part of the present study, we aim to develop and provide methods and measurement approaches that would facilitate the routine analysis of PM10 and PM2.5 samples for synthetic polymers in aerosol particles in terms of mass concentrations using Curie Point Pyrolysis-Gas Chromatography coupled with Mass Spectrometry (CPP-GC/MS). To follow this, reference standards were milled using a cryo-mill, and a calibration curve was obtained for the most common synthetic polymers present in the atmospheric environment, such as Polystyrene (PS), Polypropylene (PP), Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Low-Density Polyethylene (LDPE), Polyvinyl Chloride (PVC), Poly(methyl-methacrylate) (PMMA) and Styrene Butadiene Rubber (SBR). The present study determined the Limit of Quantification (LOQ) and Limit of Detection (LOD) of each standard by analysing it at different concentrations down to the lowest level with acceptable repeatability and accuracy. The current method of quantifying synthetic polymers was tested by spiking experiments on aerosol samples (PM10 and PM2.5) at different concentrations. This study examines open research questions in various main areas, including developing analytical methods, size-resolved sampling, and analysing NMP and TWP in ambient aerosol particles in urban, rural, and remote areas.
Keywords: Nano- and microplastics, tire wear particles, synthetic polymers, Curie Point Pyrolysis-Gas Chromatography/Mass Spectrometry.
How to cite: Kaushik, A., Mekic, M., van Pinxteren, M., and Herrmann, H.: Qualitative and quantitative analysis of synthetic polymers in ambient aerosols by Curie Point Pyrolysis-Gas Chromatography/Mass Spectrometry, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2736, https://doi.org/10.5194/egusphere-egu23-2736, 2023.
Recent studies have highlighted the importance of the atmosphere in the long-range transport of microplastic fibers (MPFs). However, both dry deposition processes and sources of MPFs are poorly understood due to their complexity in size and shape, which can be 100s $\mu m$ long, possessing round or flat cross-sections with dimensions of $O(1)\,\mu m$ thickness, and $O(10)\,\mu m$ width. Here, we develop a theory-based settling velocity model for MPFs in the atmosphere, predicting a much smaller aerodynamic size than a volumetrically equivalent spherical particle. Incorrect identification of flat fibers as cylindrical ones due to uncertainty in the thickness of sampled MPFs overestimates their dry deposition rate. Accounting for fiber thickness in sampled MPFs leads to a mean residence-time enhancement above $450\%$ compared to spherical-shaped particles, suggesting a much more efficient long-range transport of flat fibers than previously thought and that the ocean might be a major source of atmospheric plastics.
How to cite: Li, Q., Xiao, S., Cui, Y., Brahney, J., and Mahowald, N.: Long-distance atmospheric transport of microplastic fibers depends on their shapes, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3454, https://doi.org/10.5194/egusphere-egu23-3454, 2023.
Atmospheric transport has been shown to effectively disperse microplastic
particulate matter to virtually every environment on the planet. Despite this
efficient long-range transport, only few studies have examined the fundamental
mechanisms of the atmospheric transport of microplastics. Here, we present the
results of wind tunnel experiments, examining the detachment behavior of plastic
particles ranging from 38 to 125 µm in diameter from flat substrates.
Detachment was achieved solely by aerodynamic forces of the turbulent airflow.
The detachment behavior of spheric microplastic particles (Polyethylene) and
spheric glass microparticles (Borosilicate) of nominally the same diameter
(63-75 µm) are contrasted across substrates with hydrophilic to hydrophobic
surface coatings. We further examine the effect of particle-particle collisions on
the detachment behavior of both Polyethylene and glass spheres. The critical
friction velocity (u*,th), which is defined as the value at which 50% of all
microparticles detach, ranged from 0.1 to 0.3 ms −1. Particle-particle collisions
reduced the u*,th of glass, but not that for PE. Results were compared with
predictions of a Jonhson-Kendall-Roberts model. The relation of diameter to
u*,th compared well between results and prediction for Polyethylene spheres.
Glass spheres were predicted to detach at smaller u*,th than polyethylene
spheres, but detached at higher u*,th. Here, we argue that capillary forces
increased the adhesion, which is not covered by the model. The combination of
particle and substrate hydrophobicity influenced the relative humidity, at which
capillary forces increased u*,th.
How to cite: Esders, E., Sittl, S., Krammel, I., Babel, W., Papastavrou, G., and Babel, W.: Is plastic dust different from mineral dust? Results from idealized wind tunnel experiments., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12251, https://doi.org/10.5194/egusphere-egu23-12251, 2023.
We propose an inversion methodology that allows to estimate large-scale spatio-temporal emission profiles from deposition measurements of airborne microplastics from the Western USA. Traditionally, each spatio-temporal element is solved separately using linear inverse model, however, it is hard or even impossible to deduce which part of measurements is reconstructed by which spatio-temporal element. In this contribution, we treat the unknown spatio-temporal source term as a single unknown variable of a large scale optimization problem. To achieve a tractable algorithm, we propose to use the block coordinate descent (BCD) approach with each spatial element being a block of coordinates. The implied inversion method is an iterative procedure with selected linear inverse method in the inner loop. We have tested the standard linear inversion with Tikhonov regularization as well as self-tuning LS-APC (Least Squares with Adaptive Prior Covariance) Bayesian inversion as inner loop algorithms. The method converges within a small number of iterations. The results are compared with previous approaches for spatio-temporal emission estimation and the potential of the novel method is demonstrated.
How to cite: Tichý, O., Šmídl, V., and Evangeliou, N.: Spatio-temporal inversion of atmospheric microplastics emmisions using block-coordinate descent method, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12619, https://doi.org/10.5194/egusphere-egu23-12619, 2023.
Extensive use of plastic products has introduced a large amount of plastic pollutants in urban areas and even in remote environments. Nanoplastic particles, in particular, can remain airborne for weeks and transported across greater distances. Characterization of atmospheric nanoplastic particles has been limited. Sampling methods used for larger microplastic particles, such as deposition sampling, and characterization methods, such as spectroscopy, are not applicable to nanoplastic particles. Furthermore, offline sampling methods involve extensive sample preparation procedures which can alter physical and chemical properties of the particles.
In this work, we investigate the use of aerosol mass spectrometry (AMS) as an in situ technique to characterize nanoplastic particle size and composition. We generate plastic particles via three different techniques: thermal decomposition of PET plastic bottles, 3D printing (using PET, ABS, and PLA filaments) and mechanical abrasion. Particle size was characterized using a Scanning Mobility Particle Sizer (SMPS). Particles were also sampled into a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) and onto quartz filters for offline characterization using pyrolysis gas chromatography mass spectrometry (Py-GC/MS).
We found that the AMS produced real-time particle mass spectra that were very similar to those measured by Py-GC/MS analysis of particles collected on filters. The consistency between the two techniques demonstrate that AMS can provide similar information about polymeric content as Py-GC/MS, which is a widely used technique for plastic materials, but at a substantially lower detection limit and higher time resolution. On the other hand, the use chromatographic separation in Py-GC/MS provides more comprehensive evaluation of polymeric composition. For example, we were able to detect changes in ratios between monomers and dimers of PET using Py-GC/MS. Py-GC/MS was also able to provide simultaneous measurement of rubber polymers and additives in tire wear particles, an important source of particles in the near road atmosphere.
Since AMS is a commonly used technique for non-refractory components in atmospheric aerosol, optimizing the AMS for nanoplastic particle detection will help understand the sources, dynamics, mixing state and fate of nanoplastic particles in the atmosphere.
How to cite: Chan, A., Tawadrous, M., Wang, X., and Lee, A.: In situ chemical characterization of airborne nanoplastic particles by aerosol mass spectrometry, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10352, https://doi.org/10.5194/egusphere-egu23-10352, 2023.
There is growing evidence for global environmental pollution caused by plastic particles <1 µm, here referred to as nanoplastics. Nanoplastic concentrations have been below the detection limits of many methods for quite some time, and thus they have passed undetected in complex environmental samples. However, recently using Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry, many common nanosized polymers have been detected in seawater, ice and snow of rural and remote sites. In this work, we focused on the waterbodies of two contrasting sites: remote Siberian Arctic tundra and a forest landscape in southern Sweden. Nanoplastics of four polymer types (polyethylene, polyvinyl chloride, polypropylene, polyethylene terephthalate) were detected in all sampled Swedish lakes and streams (mean 563 µg/L, seven lakes, four streams). The amount of nanoplastic polymers showed a correlation with plastic demand in Europe (R2 = 0.91). In Siberia, two nanoplastic polymers (PVC and polystyrene) were detected in lakes, ponds and surface flooding, and concentrations were lower (mean 51 µg/L, three lakes, five ponds, overland flow from thawing permafrost and flooded tundra). Based on potential source analysis and HYSPLIT modelling of air mass trajectories and particle dispersion, we infer that nanoplastics predominantly arrive at both sites by atmospheric deposition from local and regional sources.
How to cite: Materic, D., Peacock, M., Dean, J., Futter, M., Maximov, T., Moldan, F., Röckmann, T., and Holzinger, R.: Atmospheric contribution of nanoplastics to rural and remote surface waters, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12323, https://doi.org/10.5194/egusphere-egu23-12323, 2023.
Nowadays, microplastics (MPs) are being found everywhere, ranging from water bottles to nearly pristine areas such as the Antarctic and Arctic regions. On the other hand, the physicochemical characteristics of airborne microplastics (AMPs) of inhalable size (<10 μm), which are particularly critical in respect of human health and climate change, are still poorly understood due to the lack of suitable analytical methods. An efficient and reliable analytical strategy is required for the investigation of inhalable AMPs, which constitute just a very small portion of ambient aerosol particles. In this study, a new analytical strategy that employs fluorescence microscopy, Raman microspectrometry (RMS), and scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX) in combination was demonstrated to be powerful for a reliable and detailed investigation of inhalable AMPs in ambient aerosols. Fluorescent staining and fluorescence microscopy can provide an efficient screening for high MP potential particles among ambient aerosols. The combined application of RMS and SEM/EDX to the same stained individual particles allows a detailed physicochemical characterization of stained particles. In this study, stained, high MP potential particles were observed with a probability of ~0.008(±0.005)%, corresponding to ~800 particles/m3, in a PM10 ambient aerosol sample. Among the stained particles of <10 μm, 27% were found to be plastics, including polystyrene, polyethylene, poly(ethylene terephthalate), and acrylonitrile butadiene styrene, and 73% were from tire/road wear. The number of inhalable AMPs was estimated to be 192(±127) particles/m3.
How to cite: Yoo, H., Lee, Y., and Ro, C.-U.: Single-particle investigation of airborne microplastics of inhalable size (<10 μm) using fluorescence microscopy, Raman microspectrometry, and scanning electron microscopy/energy dispersive X-ray spectrometry in combination, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11138, https://doi.org/10.5194/egusphere-egu23-11138, 2023.
