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Polyethylene terephthalate has been widely used in the packaging industry. Degraded PET micro(nano)plastics could pose public health concerns following release into various environments. This study focuses on PET degradation under ultraviolet radiation using the NIST SPHERE facility at the National Institute of Standards and Technology in saturated humidity (i.e., ≥95% relative humidity) and dry conditions (i.e., ≤5% relative humidity) with varying temperatures (30 °C, 40 °C, and 50 °C) for up 20 days. ATR-FTIR was used to characterize the chemical composition change of degraded PET as a function of UV exposure time. The results showed that the cleavage of the ester bond at peak 1713 cm−1 and the formation of the carboxylic acid at peak 1685 cm−1 were significantly influenced by UV radiation. Furthermore, the formation of carboxylic acid was considerably higher at saturated humidity and 50 °C conditions compared with dry conditions. The ester bond cleavage was also more pronounced in saturated humidity conditions. The novelty of this study is to provide insights into the chemical degradation of PET under environmental conditions, including UV radiation, humidity, and temperature. The results can be used to develop strategies to reduce the environmental impact of plastic pollution.

Microplastics are tangible particles of less than 0.2 inches in diameter that are ubiquitously distributed in the biosphere and accumulate in water bodies. During the east-coast hot summers (23–29 °C) of 2021 and 2022, June through September, we captured copious amounts of the jellyfish Chrysaora chesapeakei, a predominant species found in the Patuxent River of the Chesapeake Bay in Maryland on the United States East Coast. We determined that their gelatinous bodies trapped many microplastics through fluorescent microscopy studies using Rhodamine B staining and Raman Spectroscopy. The chemical nature of the microplastics was detected using gas chromatography–mass spectroscopy headspace (SPME-GC-MS) and solvent extraction (GC-MS) methods through a professional commercial materials evaluation laboratory. Numerous plastic-affiliated volatile organic compounds (VOCs) from diverse chemical origins and their functional groups (alkanes, alkenes, acids, aldehydes, ketones, ethers, esters, and alcohols) along with other non-microplastic volatile organic compounds were observed. Our findings corroborate data in the available scientific literature, distinguishing our finding’s suitability.