Airborne Microplastics in Indoor and Outdoor Environments of a Developing Country in South Asia: Abundance, Distribution, Morphology, and Possible Sources

Airborne microplastics (AMPs) have been reported in indoor and outdoor air in high-income countries and are expected to be a significant contributor to daily microplastic (MP) exposure for human beings. To date, there are only a handful of studies in lower-middle-income countries. In this study, AMPs from 5000 to 50 mu m were sampled across selected areas of Sri Lanka using an active sampling technique. Suspected AMPs were further characterized using Fourier transform infrared spectroscopy. MP concentrations were higher indoors compared to outdoor air (0.13-0.93, compared to 0.00-0.23 particles/m(3), respectively). The types of indoor MPs were related to indoor-generating sources, vacuum and the occupants lifestyles. The highest outdoor MP abundance pump was found near an industrial zone, followed by urban and inland locations in high-density areas. The dominant size range of MPs was 100-300 mu m, and the only shapes observed indoors and outdoors were fibers (98%) and fragments. Polyethylene terephthalate was the most prominent MP type, followed by polyester, indicating that textile fibers could be the major source of these AMPs. This study provides the first report on AMPs in Sri Lanka. Considering population growth and industrialization, further research should evaluate possible trends and health risks upon inhalation.

Automated summary

This study discovered airborne microplastics in indoor and outdoor air in Sri Lanka. Indoor microplastic concentrations were higher than outdoor concentrations and were related to indoor-generating sources, vacuum use, and occupants' lifestyles. The highest outdoor microplastic abundance was found near an industrial zone. The dominant microplastic type was polyethylene terephthalate, followed by polyester.