Aerosols

Microplastic atmospheric transport:

Atmospheric microplastic is a topic of raising concern, and particles of different sizes and shapes have been observed in precipitations and atmospheric samples all over the world, including in very remote regions such as the Arctic and high mountains glaciers. Exploiting the capability of FLEXPART, we try to reconstruct the pathways of transport of these particles and to understand their sources. For this purpose, we developed the model (Tatsii et al 2023) to take into account also the longer atmospheric lifetime of irregular and very elongated or very flat particles, as microplastic can be (e.g. fibers, films, fragments). We also seek to characterize the emissions of microplastic from the main sources and the consequent impact on the atmospheric concentration. We build the emissions starting from schemes as FLEXDUST (Zwaaftink et al., 2016, 2017) or the Grythe et al. 2014 sea spray function to estimate the fluxes of microplastic. With this approach, we estimated the microplastic emissions happening alongside the dust resuspension from arid regions for example, or the flux of microplastic escaping from the surface of the sea due to wave breaking and bubble bursting. The dispersion in the atmosphere is then evaluated using global 3-dimensional simulations of FLEXPART forward trajectories run on ECMWF reanalysis data (ERA5). In addition to the atmospheric concentration, the model allows also to evaluate the redistribution and the deposition fluxes (wet and dry) of the particles back to the surface, allowing for comparison with the current measurements of deposition rates. Overall, we aim to characterize the atmospheric sources and the pathways of transport of microplastic pollution, to better delineate their possible impacts and possible mitigation actions.

Scientists:
Silvia Bucci, Ioanna Evangelou, Daria Tatsii, Andreas Stohl