The abundance and distribution of microplastic (<5 mm) has become a growing concern, particularly over the past decade. Research to date has focused on water, soil, and organism matrices but generally disregarded air. We explored airborne microplastic inside and outside of buildings in coastal California by filtering known volumes of air through glass fiber filters, which were then subsequently characterized with a variety of microscopy techniques: gross traditional microscopy, fluorescent microscopy following staining with Nile red, micro-Raman spectroscopy, and micro-Fourier transform infrared (µFT-IR) spectroscopy. Microplastics permeated the air, with indoor (3.3 ± 2.9 fibers and 12.6 ± 8.0 fragments m–3; mean ± 1 SD) harboring twice as much as outdoor air (0.6 ± 0.6 fibers and 5.6 ± 3.2 fragments m–3). Microplastic fiber length did not differ significantly between indoor and outdoor air, but indoor microplastic fragments (58.6 ± 55 µm) were half the size of outdoor fragments (104.8 ± 64.9 µm). Micro-Raman and FT-IR painted slightly different pictures of airborne plastic compounds, with micro-Raman suggesting polyvinyl chloride dominates indoor air, followed by polyethylene (PE) and µFT-IR showing polystyrene dominates followed by PE and polyethylene terephthalate. The ubiquity of airborne microplastic points to significant new potential sources of plastic inputs to terrestrial and marine ecosystems and raises significant concerns about inhalation exposure to humans both indoors and outdoors.

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EXPRESS：室内和室外空气质量的微塑料不同：来自多种显微镜方法的见解

微塑料（<5 毫米）的丰度和分布越来越受到关注，特别是在过去十年中。迄今为止的研究主要集中在水、土壤和有机体基质上，但通常忽略了空气。我们通过玻璃纤维过滤器过滤已知体积的空气，探索了加利福尼亚沿海建筑物内部和外部的空气中微塑料，然后用各种显微镜技术对其进行了表征：大体传统显微镜、尼罗红染色后的荧光显微镜、微拉曼光谱和微傅立叶变换红外 (µFT-IR) 光谱。微塑料渗透空气，室内（3.3 ± 2.9 纤维和 12.6 ± 8.0 碎片 m-3；平均值 ± 1 SD）含有两倍于室外空气（0.6 ± 0.6 纤维和 5.6 ± 3.2 碎片 m-3）。室内和室外空气中的微塑料纤维长度没有显着差异，但室内微塑料碎片 (58.6 ± 55 µm) 是室外碎片大小 (104.8 ± 64.9 µm) 的一半。显微拉曼和 FT-IR 描绘了空气中塑料化合物的略有不同的图片，微拉曼表明聚氯乙烯在室内空气中占主导地位，其次是聚乙烯 (PE) 和 µFT-IR 显示聚苯乙烯占主导地位，其次是 PE 和聚对苯二甲酸乙二醇酯。空气中微塑料的普遍存在表明了陆地和海洋生态系统塑料输入的重要新潜在来源，并引起了人们对室内和室外吸入暴露于人类的重大担忧。显微拉曼和 FT-IR 描绘了空气中塑料化合物的略有不同的图片，微拉曼表明聚氯乙烯在室内空气中占主导地位，其次是聚乙烯 (PE) 和 µFT-IR 显示聚苯乙烯占主导地位，其次是 PE 和聚对苯二甲酸乙二醇酯。空气中微塑料的普遍存在表明了陆地和海洋生态系统塑料输入的重要新潜在来源，并引起了人们对室内和室外吸入暴露于人类的重大担忧。显微拉曼和 FT-IR 描绘了空气中塑料化合物的略有不同的图片，微拉曼表明聚氯乙烯在室内空气中占主导地位，其次是聚乙烯 (PE) 和 µFT-IR 显示聚苯乙烯占主导地位，其次是 PE 和聚对苯二甲酸乙二醇酯。空气中微塑料的普遍存在表明了陆地和海洋生态系统塑料输入的重要新潜在来源，并引起了人们对室内和室外吸入暴露于人类的重大担忧。