Household indoor microplastics within the Humber region (United Kingdom): quantification and chemical characterisation of particles present

Knowledge regarding the presence of suspended microplastics (MPs) within the air is lacking, especially indoors, yet the importance of indoor air quality and human health is rising. This study is the first to report MPs within multiple homes over a 6-month period, with concentrations exceeding previous outdoor studies. Twenty households, within the City of Hull and Humber region, U.K., were passively sampled, each month, collecting atmospheric fallout at head height for subsequent particle quantification, characterisation and μFTIR validation (n = 3061). A household average of 1414 MP m−2 day−1 ± 1022 (mean ± SD) was observed. Smaller (5–250 μm), fibrous, particles were the most abundant (90%), representing types most likely to enter the human body and cause physiological harm. Polyethylene terephthalate (PET) was present in 90% of samples and accounted for 62% of MPs. Additionally, polyamide (PA) and polypropylene (PP) were common. Results indicate that humans are exposed to significantly (1–45 times) higher concentrations, and ranges, of MPs within homes compared with the outdoor environment. In conclusion, the size range and types of MPs observed will inform laboratory experiments, using either human tissue culture or other approaches. This will allow determination of the wider implications on human health using realistic levels and representative types of indoor MPs