Quantifying Atmospheric Small Micro- and Nanoplastics (MNP) in The Netherlands

Airborne small micro- and nanoplastics (MNP) are ubiquitous in the atmosphere and pose a potential health risk, as they can enter deep into the lungs and into the bloodstream. Accurate quantification of atmospheric MNP load, source attribution, and deposition is crucial for the assessment of the plastic burden and fluxes.

In March-April 2025, the CAINA project conducted an extensive field campaign in the Netherlands. Quartz filter samples were taken at Cabauw, an urban background monitoring site situated within an agricultural landscape and influenced by its proximity to the major urban centers of Rotterdam and Amsterdam. The samples were taken using a high-volume air sampler with a PM2.5 size cut-off. Twenty filters were collected during the campaign. Each filter represented a 24-hour continuous air sampling period. These filters are analyzed in the laboratory for inorganic ions, organic aerosol composition, and MNP quantification.

The MNP load was quantified using a Thermal Desorption-Proton Transfer Reaction-Mass Spectrometer (TD-PTR-MS) together with Multicomponent Multivariate Standard Addition (MMSA). Filter aliquots were heated from 50°C to 350°C to desorb material on the filter, and detected by PTR-MS. By incrementally adding plastic standards to the samples, mass concentrations of polystyrene (PS), polyethene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP) can be retrieved accurately by applying Non-Negative Matrix Factorization (NMF).

Using atmospheric back trajectory analysis, the origin of the sampled air mass will be discussed. Distinct air mass regimes were observed, characterized by periods of relatively clean air associated with northerly winds and periods of elevated pollution associated with easterly air mass transport.