Atmospheric Deposition of Microplastics and Anthropogenic Cellulose in an Inland Suburban Florida Town

Abstract

Atmospheric deposition has recently been identified as an important pathway for microplastic (MP) and anthropogenic cellulose particle (ACP) pollution. This study presents the first examination of atmospheric fallout of MPs and ACPs in an inland, suburban area of central Florida. From September 2023 to February 2024, particulate matter was collected at a residential site in Oviedo, FL, using replicate glass passive deposition jars during wet and dry deposition events (n = 59). Samples were filtered, visually identified under microscopy, and analyzed by Fourier Transform Infrared Spectroscopy (FTIR) to determine polymer composition. A total of 1,809 particles were identified, including 481 suspected MPs and 1,328 ACPs, with ACPs significantly outnumbering MPs (p < 0.0001). Fibers were the dominant morphology (> 96%), and most particles measured between 100-1,000 µm in length. Polymer analysis identified nylon, polystyrene, polyethylene terephthalate (PET), and polyvinyl chloride (PVC) among MPs, while ACPs included modified cellulose forms such as microcrystalline cellulose and lyocell. No significant differences were found between wet and dry deposition modes or correlations between rainfall and deposition rate. A deposition rate was approximated to 3,600 total particles per m² per day (95% CI: 3.0x10³–4.2x10³). These findings are the first evidence of atmospheric fallout of synthetic pollutants in Florida’s suburban, inland environment and suggest cellulose-based fibers may be more prevalent than petrochemical polymers. Inhalation of airborne particles has previously been documented in humans and invertebrates, making it imperative that steps be taken to minimize further introduction of airborne micropollutants.