Microplastics suspended in dust from different indoor environments in Barranquilla, Colombia: Predominant microparticles?

Considering that microplastics (MPs) are classified as ubiquitous pollutants, that air quality affects human health, and that people remain indoors most of the time, the need has arisen to evaluate the exposure to MPs within the suspended dust in indoor environments. With this objective, the present study carried out passive sampling to analyze the precipitation of microparticles in some indoor residential environments (2 apartments) and workplaces (an office, a pastry shop, a gift shop, and a paint shop) in Barranquilla, Colombia. The quantification and physical characterization of microparticles were carried out under a stereomicroscope, and the chemical characterization was carried out by infrared microspectroscopy (μFTIR). The highest average concentration of MPs in the apartments was found in the air-conditioned rooms (1.1 × 10 MP/m/day), and concerning the workplaces, the gift shop and the paint shop were the spaces with a higher proportion of MPs (6.0-6.1 × 10 MP/m/day), with polyesters being the main synthetic polymers, but being semi-synthetic particles the predominant among the samples. Regarding its morphology, fibers were the most abundant shape (>90%), grouping mainly in the 1000-5000 μm range, while the few fragments found were mostly grouped below 50 μm. Exposure by inhalation of MPs in adults was estimated between 1.7 × 10-1.6 × 10 MP/kg/day, while by ingestion it ranged between 2.7 × 10-2.4 × 10 MPs/kg/day. On the other hand, within our research, a significant presence of non-plastic microparticles was found, which reached up to 69% in analyzed samples, corresponding mainly to cotton and cellulose, so we suggest that these should also be included in future studies that aim to estimate potential health implications from exposure to suspended micropollutants.