State Key Laboratory of Coal Resources and Safe Mining & College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
State Key Laboratory of Coal Resources and Safe Mining & College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China.
Sci Total Environ. 2022 Sep 10;838(Pt 1):155989. doi: 10.1016/j.scitotenv.2022.155989. Epub 2022 May 14.
Airborne microplastics (MPs) pollution is an environmental problem of increasing concern, due to the ubiquity, persistence and potential toxicity of plastics in the atmosphere. In recent years, most studies on MPs have focused on aquatic and sedimentary environments, but little research has been done on MPs in the urban atmosphere. In this study, a total of ten dustfall samples were collected in a transect from north to south across urban Beijing. The compositions, morphologies, and sizes of the MPs in these dustfall samples were determined by means of Laser Direct Infrared (LDIR) imaging and Field Emission Scanning Electron Microscopy (FESEM). The number concentrations of MPs in the Beijing dustfall samples show an average of 123.6 items/g. The MPs concentrations show different patterns in the central, southern, and northern zones of Beijing. The number concentration of MPs was the highest in the central zone (224.76 items/g), as compared with the southern zone (170.55 items/g), and the northern zone (24.42 items/g). The LDIR analysis revealed nine compositional types of MPs, including Polypropylene (PP), Polyamide (PA), Polystyrene (PS), Polyethylene (PE), Polyethylene Terephthalate (PET), Silicone, Polycarbonate (PC), Polyurethane (PU) and Polyvinylchloride (PVC), among which PP was overall dominant. The PP dominates the MPs in the central zone (76.3%), and the PA dominates the MPs in the southern zone (55.86%), while the northern zone had a diverse combination of MPs types. The morphological types of the individual MPs particle include fragments, pellets, and fibers, among which fragments are dominant (70.9%). FESEM images show the presence of aged MPs in the Beijing atmosphere, which could pose a yet unquantified health risk to Beijing's residents. The average size of the MPs in the Beijing samples is 66.62 μm. Our study revealed that the numbers of fibrous MPs increase with the decrease in size. This pollution therefore needs to be carefully monitored, and methods of decreasing the sources and mitigations developed.
空气中的微塑料(MPs)污染是一个日益受到关注的环境问题,这是由于塑料在大气中无处不在、持久存在且具有潜在毒性。近年来,大多数关于 MPs 的研究都集中在水生和沉积环境中,但对城市大气中的 MPs 研究甚少。在这项研究中,我们在北京市从北到南的一条线上共采集了十个降尘样本。通过激光直接红外(LDIR)成像和场发射扫描电子显微镜(FESEM),确定了这些降尘样本中 MPs 的组成、形态和大小。北京降尘样本中 MPs 的数量浓度平均为 123.6 项/g。MPs 浓度在北京市中心、南部和北部呈现不同的模式。中心区(224.76 项/g)的 MPs 浓度最高,其次是南部(170.55 项/g)和北部(24.42 项/g)。LDIR 分析揭示了 9 种 MPs 组成类型,包括聚丙烯(PP)、聚酰胺(PA)、聚苯乙烯(PS)、聚乙烯(PE)、聚对苯二甲酸乙二醇酯(PET)、硅酮、聚碳酸酯(PC)、聚氨酯(PU)和聚氯乙烯(PVC),其中 PP 总体占主导地位。PP 主导着中心区(76.3%)的 MPs,PA 主导着南部区(55.86%)的 MPs,而北部区则存在多种 MPs 类型的组合。单个 MPs 颗粒的形态类型包括碎片、小球和纤维,其中碎片占主导地位(70.9%)。FESEM 图像显示,北京大气中存在老化的 MPs,这可能对北京居民造成尚未量化的健康风险。北京样本中 MPs 的平均尺寸为 66.62 μm。我们的研究表明,纤维状 MPs 的数量随着尺寸的减小而增加。因此,这种污染需要仔细监测,并开发减少来源和缓解措施的方法。