Nanoplastic particles are inadequately characterized environmental pollutants that have adverse effects on aquatic and atmospheric systems, causing detrimental effects to human health through inhalation, ingestion and skin penetration^1,2,3. At present, it is explicitly assumed that environmental nanoplastics (EnvNPs) are weathering fragments of microplastic or larger plastic debris that have been discharged into terrestrial and aquatic environments, while atmospheric EnvNPs are attributed solely to aerosolization by wind and other mechanical forces. However, the sources and emissions of unintended EnvNPs are poorly understood and are therefore largely unaccounted for in various risk assessments⁴. Here we show that large quantities of EnvNPs may be directly emitted into the atmosphere as steam-laden waste components discharged from a technology commonly used to repair sewer pipes in urban areas. A comprehensive chemical analysis of the discharged waste condensate has revealed the abundant presence of insoluble colloids, which after drying form solid organic particles with a composition and viscosity consistent with EnvNPs. We suggest that airborne emissions of EnvNPs from these globally used sewer repair practices may be prevalent in highly populated urban areas⁵, and may have important implications for air quality and toxicological levels that need to be mitigated.

纳米塑料颗粒是对水生和大气系统有不利影响的环境污染物，通过吸入、摄入和皮肤渗透^1,2,3对人类健康造成不利影响。目前，明确假设环境纳米塑料 (EnvNPs) 是已排放到陆地和水生环境中的微塑料或较大塑料碎片的风化碎片，而大气 EnvNPs 仅归因于风和其他机械力的雾化作用。然而，人们对意外 EnvNPs 的来源和排放知之甚少，因此在各种风险评估中基本上没有考虑到⁴. 在这里，我们表明大量的 EnvNPs 可能会作为通常用于修复城市地区下水道管道的技术排放的富含蒸汽的废物成分直接排放到大气中。对排放的废冷凝液进行的综合化学分析表明，大量存在不溶性胶体，这些胶体在干燥后形成固体有机颗粒，其组成和粘度与 EnvNPs 一致。我们认为，这些全球使用的下水道维修做法产生的 EnvNP 空气排放可能在人口稠密的城市地区很普遍⁵，并且可能对需要缓解的空气质量和毒理学水平产生重要影响。