Airborne microplastics (<5 mm in size) are considered as emerging contaminants in recent times. Due to their small size, density and non-spherical shapes (e.g., fibers), they are easily resuspended from the land with turbulent flows and the surface of the ocean as bubbles burst and later transported by wind. Accordingly, atmospheric transport is a major pathway for microplastics to reach remote regions such as the Poles and mountains and deposit on snow and ice surfaces. Microplastics are hazardous to marine and terrestrial ecosystems and can be harmful to human health through their introduction of toxic organic pollutants and potential interference with usual biological processes. They are also colourful particles, absorb radiation and may affect Earth's radiative balance directly, while enhanced plastic production needs larger consumption of fossil fuels, thus affecting climate indirectly.
In MAGIC, we resolve all these uncertain atmospheric processes, while we build standard operating procedures for the robust detection of atmospheric microplastics. We model non-spherical structures of atmospheric microplastics directly in FLEXPART model improving long-range transport and calculate their sources using observations and an inverse modelling algorithm. Furthermore, we study how these contaminants are resuspended from the land (turbulent-induced) and/or the ocean (bubble bursts) using microscale modelling (PALM model). We develop robust methodologies to sample and accurately measure atmospheric microplastics from filters with offline thermal extraction/desorption gas chromatography mass spectrometry (TED-GC-MS) and thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) analysis and complement the results against micro-RAMAN spectroscopy. After we define their atmospheric distribution and levels accurately, we study its impact on the present and future climate using radiative transfer models.
Microplastics (MPs) have been recognised today as the most emerging contaminants. Around 5 billion tonnes of plastic have accumulated in ecosystems worldwide, thousands are floating and decompose in the oceans, while research has shown that MPs also permeate freshwater and terrestrial environments.
However, it is unknown how airborne MPs are emitted or transported and what their main origin is, despite that they have been detected in urban and remote regions. This is largely due to limitations in the determination methodology that prevents accurate quantification of MP sources. MAGIC will focus on developing a robust methodology to measure airborne MPs, online and offline. The later will allow for accurate quantification of MP sources using Bayesian inverse modelling. To study long-range transport (WP1), physical properties are needed by dispersion models (WP3). MAGIC will identify size distribution of atmospheric MPs (WP3), and improve dispersion models (WP1) to account for different MP shapes (WP1) and their ability to act as cloud condensation or ice nuclei.
It has been reported that deposited MPs can be remobilised by strong winds both from the land and the ocean, allowing secondary transport, similar to the grasshopper effect of POPs or the resuspension of dust. MAGIC will investigate the relative parameters affecting MP resuspension from the surface and their contribution to emissions, by means of large-eddy simulation modelling (WP2).
MPs are colourful particles, thus absorb solar radiation and change surface albedo and/or cloud microphysical properties. MAGIC will investigate their climate impact using a radiative transfer model (WP4).
MAGIC’s results will be relevant to evidence-based policy. MAGIC’s innovations are (i) conceptual, i.e., unstudied aspects of emerging climate feedbacks, (ii) methodological, i.e., development of novel methodologies, and (iii) geographical, i.e. a focus on the remote regions and the High Arctic.