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, 23–28 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, 23–28 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  0.5^o x 0.5^o 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, 23–28 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, 23–28 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, 23–28 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, 23–28 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, 23–28 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, 23–28 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, 23–28 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, 23–28 Apr 2023, EGU23-17295, https://doi.org/10.5194/egusphere-egu23-17295, 2023.