Roberto Rosal
Professor of Chemical Engineering in the Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering at the University of Alcalá
In this article, the researchers conducted a predictive physics study. Rather than obtaining actual samples of plastic particles captured from the atmosphere, they prepared laboratory samples by grinding materials purchased from a commercial supplier. Using an advanced electron microscopy technique called AC-TEM-EELS, they individually measured how each color of plastic absorbs energy and repeated the process with the same materials artificially aged in the laboratory.
The research demonstrated that colored plastics absorb more energy than colorless ones, as expected, and linked this to their mass within the experimental set of particles they analyzed. Finally, they calculated the potential impact on global warming based on the total mass of plastic suspended per square meter of air, calculated using a dispersion model fed by global plastic emissions inventories and assumptions about the residence time of the particles in the atmosphere.
The problem with this type of estimate, as has already been highlighted in this same media outlet, is that they may be overestimated by many orders of magnitude. It is, therefore, a model of models where the total mass of plastics does not come from actual sampling, but from simulations based on previous inventories that are quite debatable. Although such models are not entirely without merit, their limitations are numerous, and the results regarding their contribution to atmospheric warming must be interpreted with great caution.