The report presents a comprehensive review of the current state of knowledge on micro‑ and nanoplastics in the atmosphere, with a particular focus on airborne particles smaller than 5 mm that can be inhaled. It highlights that the global production of plastics reached almost 390 million tonnes in 2021, of which 57 million tonnes were produced in Europe, and that this surge has led to a rapid increase in micro‑ and nanoplastic pollution in land, water, food and air. The authors note that while soil, water and food matrices have been extensively studied, the occurrence of microplastics in indoor and outdoor air has received comparatively little attention. Existing studies have mainly relied on deposition samples and provide limited information on the smallest size fractions, such as PM10 (thoracic particles) and PM2.5 (alveolar particles), which are most relevant for human inhalation risk. The report therefore stresses the need for accurate atmospheric concentration data to assess long‑range transport and exposure.

A key technical contribution of the study is the systematic evaluation of sampling, extraction and analytical methods used in the literature. The authors identify a lack of harmonised protocols, which hampers comparability across studies. They compile a table of relevant ISO and CEN documents that can serve as a foundation for future standardisation. For example, ISO 4484‑2:2023 provides qualitative and quantitative analysis guidelines for microplastics from textiles, while ISO 24187:2023 outlines general principles for environmental microplastic analysis, including particle‑size classification and sampling apparatus. The report also references CEN EN 12341:2023 and EN 14907:2005, which describe gravimetric measurement methods for PM10 and PM2.5 mass concentrations in ambient air. By mapping these standards against the specific challenges of airborne microplastics, the authors demonstrate that current gravimetric techniques can be adapted for microplastic monitoring, but that additional steps—such as polymer identification by Raman or FTIR spectroscopy—are required to confirm plastic origin. The review further details the main sources of airborne microplastics, distinguishing between indoor contributors such as textiles, floor coverings, occupancy, cleaning habits and air‑conditioning systems, and outdoor sources including road dust, tyre wear and oceanic inputs. The authors point out that particles smaller than 3 µm, which can penetrate deep into the lungs, are under‑represented in current datasets, underscoring a critical knowledge gap.

The project was carried out by a consortium of researchers led by the Joint Research Centre (JRC) of the European Commission, with contributions from specialists in environmental chemistry, aerosol science and polymer analysis. The authors—Otmar Geiss, Hind El Hadri, Barouch Giechaskiel, Tawfiq Al Wasif Ruiz, Jean‑Philippe Putaud and Josefa Barrero—represent a multidisciplinary team that combined expertise in microplastic sampling, analytical chemistry, and risk assessment. The study was funded by the European Commission under its Horizon programme, reflecting the policy relevance of the findings for the European Strategy for Plastics and the Green Deal. The JRC Microplastics group, which coordinates the research, maintains an open communication channel (JRC‑MICROPLASTICS@ec.europa.eu) and hosts the EU Science Hub website, where the full report and related datasets are made publicly available. The collaborative framework enabled the integration of laboratory data, field measurements and policy analysis, providing a robust evidence base for the development of future regulatory instruments aimed at reducing airborne microplastic exposure.