Global Modeling of Microplastics in the Atmosphere

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.