Researchers examine sources of atmospheric microplastics. Microplastic pollution is a major environmental issue. By combining in situ observations of microplastic accumulation with an atmospheric transport model, Janice Brahney, Natalie Mahowald, and colleagues examined major sources of atmospheric microplastics as well as the locations where such pollution is concentrated. The authors collected atmospheric microplastics data from the western United States over a 14-month period. Eighty-four percent of atmospheric microplastics came from road dust, whereas 11% came from sea spray and 5% came from agricultural soil dust. Terrestrial microplastic pollution was deposited on ocean surfaces, and oceanic microplastic pollution was deposited on land. Most continents imported more plastic than they exported. Hotspots for terrestrial microplastic sources and accumulation included Europe, Eastern Asia, the Middle East, India, and the United States. Overall, the greatest concentration of atmospheric microplastics was estimated to be over the ocean. Depending on size, microplastics remained in the atmosphere from approximately 1 hour to 6.5 days, the latter duration being sufficient for cross-continental transport. Antarctica also received microplastic pollution from the atmosphere, despite having zero microplastic emissions. The findings suggest that even after atmospheric microplastics settle on land or in water, they may reenter the atmosphere, according to the authors.
Article #20-20719: "Constraining the atmospheric limb of the plastic cycle," by Janice Brahney et al.
MEDIA CONTACT: Janice Brahney, Utah State University, Logan, UT; tel: 435-938-8966; email: janice.brahney@usu.edu ; Natalie Mahowald, Cornell University, Ithaca, NY; tel: 607-255-5166; email: mahowald@cornell.edu
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Proceedings of the National Academy of Sciences