The increasing prevalence of plastic pollution globally has made the atmospheric deposition of microplastics (MPs) a critical issue, necessitating a deeper understanding of its environmental and human health impacts. This study is the first to quantify and characterize atmospheric MP deposition in the Eastern United States. Sampling was conducted at two locations: the National Atmospheric Deposition Program (NADP) Site NTN VA13 and Virginia Tech's Kentland Farm in remote South Central Appalachia, from March to September 2023. Each site underwent five sampling periods, with collections spanning 21 days each. Samples were processed to remove biological material, and the presence of MPs was confirmed using Raman spectroscopy, which matched particles based on polymer similarity. The average atmospheric MP deposition in South Central Appalachia was determined to be 68 MPs m^-2 d^-1. Most confirmed MPs were fibers, with polyethylene terephthalate (PET) being the most abundant polymer type identified. This study's average MP deposition rate is comparable to rates reported in other studies using similar methodologies and landscapes. When scaled to the entirety of South Central Appalachia, covering an area of over 94,000 km² and home to five million people, the estimated yearly MP deposition is approximately 321 metric tonnes. Our findings underscore the prevalence of atmospheric MP deposition in rural areas of the United States and highlight the importance of establishing a new network for MP deposition within the NADP.

¹ Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA

² Healthy Earth, London, England

* Corresponding Author: hosein@vt.edu