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 pose a significant environmental threat, and understanding their sources and generation mechanisms is crucial for mitigation efforts. This study investigates the effects of ultraviolet intensity, temperature, and relative humidity on the degradation of polyethylene terephthalate (PET) plastics and the subsequent formation of microplastic particles. PET samples were exposed to ultraviolet (UV) radiation under various environmental conditions using the SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) accelerated weathering device at the National Institute of Standards and Technology (NIST). Attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and laser confocal scanning microscopy (LSCM)/atomic force microscopy (AFM) were employed to characterize the chemical and morphological changes on the weathered surfaces. This study’s findings reveal that temperature and relative humidity significantly influence the rate of photodegradation and the characteristics of the generated microplastics. Higher temperatures and increased humidity accelerated the degradation process, leading to a higher abundance of microplastic particles. However, larger particles were observed at higher temperatures due to aggregation. These results underscore the importance of considering environmental factors when assessing the fate and transport of microplastics in the environment. Developing strategies to reduce plastic pollution and mitigate the generation of microplastics is essential for protecting ecosystems and human health.

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 are significantly influenced by UV radiation. Furthermore, the formation of carboxylic acid was considerably higher at saturated humidity and 50 °C conditions compared to 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.

Objective: Young adults of age 18–29 years old account for the most COVID-19 cases in the US, and ethnic groups were affected disproportionately. Correctly wearing a face mask remains a critical intervention for COVID-19 mitigation. The study aimed to examine how well Historically Black Colleges and Universities (HBCUs) residents adhered to mask wearing during the pandemic. Methods: We conducted an observational study on an urban HBCU campus and the neighborhoods in Maryland for 13 weeks in spring 2021. Results: Of 1926 (1126 on campus; 800 off campus) persons observed, 89.8% wore masks, with 83.5% covering their mouths and noses. The HBCU campus showed better mask adherence than neighborhoods (92.0% vs. 86.7%). The most common improper mask wearing was nose out, followed by only-on-chin. Cloth and surgical masks were worn the most. Conclusion: The HBCU campus and neighborhood settings presented a high rate of facemask use during the pandemic.

The gut microbiota plays a crucial role in early childhood development. Dysbiosis in this community has been linked to risk of disease. The transition from an exclusive milk-based diet to complementary feeding and eventual weaning is crucial for the development and maturation of the gut microbiota. However, the impact of breastfeeding duration during the complementary feeding period (typically 6 to 24 months of age) on microbial development trajectories remains incompletely characterized. Here, we investigated whether prolonged breastfeeding during the complementary feeding window influences gut microbiota succession by comparing children who continued breastfeeding with those who were fully weaned at the same ages. We analyzed 16S rRNA gene sequencing profiles of fecal samples collected from a cohort of Peruvian children at 6, 12, 18, and 24 months of age. Samples were categorized into two groups: a complementary feeding group (BF), which received both complementary foods and breast milk, and a post-weaning group (NBF), which had stopped receiving breast milk for over 7 days. We conducted both alpha and beta diversity to assess within- and between-sample microbial variation. Relative abundances of microbial taxa at the phylum and genus levels were also quantified. The results showed a clear age-related increase in both species richness and species evenness across early childhood, while BF had more gradual changes relative to NBF. Marked differences in community composition were observed between BF and NBF children at 12, 18, and 24 months, respectively. Children who continued breastfeeding maintained a Bifidobacterium-rich, lower-diversity microbiota for a longer period, whereas weaned children at the same age exhibited accelerated microbiota development toward an adult-like profile enriched in Bacteroidota and Bacillota (formerly Firmicutes). These findings suggest that breastfeeding during the complementary feeding period exerts a significant influence on gut microbiota development through the first two years of life, which is most likely independent of complementary food. The study provides potential implications for children’s health and nutrition guidelines from a perspective of gut microbiota succession.