One study quantified the release of microplastics into the atmosphere from sea fog and showed that the ocean releases between 0.02 and 7.4 million tons of microplastics each year, so a detailed inventory of marine microplastics is needed for an accurate assessment. New research quantifies the amount of microplastics released into the air by sea fog. When ocean bubbles collapse, they release tiny particles, such as salt or fragments of organic matter, into the atmosphere. This activity transfers large amounts of material, affecting the world's climate by changing the atmosphere's radiation balance and acting as a nucleus for cloud formation.
But will sea fog also throw microplastics, which are ubiquitous in the ocean, into the atmosphere? Luc Deike and colleagues used high-speed photography in laboratory experiments to explore the physical processes behind explosive jets of microplastic bubbles.
Experimental results show that microplastic particles with diameters between 10 μm and 280 μm will be dispersed from seawater into the air in a form called "jet droplets". These small droplets are ejected from ruptured sea bubbles. These tiny water droplets float through the air carrying their plastic cargo. Once airborne, the water may evaporate and the plastic may become airborne on wind currents.
Using estimates of the concentration of microplastics in the ocean, scientists can estimate the total amount of microplastics emitted into the world's oceans. According to the authors' calculations, the annual release of plastic into the ocean ranges from 0.02 megatons (44,000 pounds) to 7.4 megatons (16,000,000 pounds), with the best guess being 0.1 megatons (220,000 pounds). Inventories of marine microplastic concentrations are now needed to reduce uncertainty in the quantification of marine microplastic emissions, the authors say.