The Occurrence and Abundance of Microplastics in Dust Settled in Indoor and Outdoor Environments of Residential Houses in Kermanshah

Microplastics are persistent environmental pollutants. Their presence in water resources, air and food chains is a growing concern all over the world. Since air is a strong environmental substrate, the release and effects of airborne microplastics can remain localized or go far beyond the point of release. In this study, the indoor and outdoor air pollution of residential houses in Kermanshah, Iran, was investigated.

In order to collect samples, different parts of the houses, including bedroom, living room, kitchen, corridor, yard and roof, were selected as the sampling points. Ten stations were selected as the sampling points. After washing with distilled water, the samples were transferred to the laboratory through a fiberglass filter (diameter 47 mm, 1.1 μm pore size) and filtered using a vacuum pump. After preparing and extracting the above samples, the visual method was used for the quantitative and qualitative detection of the microplastics.

The results of the study confirmed the presence of microplastics in all the samples. The frequency of microplastics was minimum 158 and maximum 4480 per square meter. The indoor samples were significantly more polluted than the outdoor samples. The highest frequency was related to black fiber, which can be attributed to a textile origin. Also, more than 78% of the samples were determined to be less than 500 micrometers in size.

Exposure to microplastic-contaminated air is inevitable, and currently, our knowledge about the release of microplastics in indoor air as well as the factors affecting microplastic transmission is lacking. There is a need for more studies focusing on these issues, because they are of great importance in assessing the potential risk of microplastics on human health.