Airborne microplastics and fibers in indoor residential environments in Aveiro, Portugal

Abstract Airborne microplastics and fibers in indoor and outdoor air may lead to human exposure through inhalation. Sampling was performed to determine concentrations of microplastics and fibers in the indoor air of living rooms of five houses in Aveiro, Portugal. Developments on contamination control measures allowed to reduce cross contamination (up to 98%) and improved results reliability. Living rooms presented a median of 0.9 fibers m−3, 0.7 non-fiber microplastics m−3, or a total of 1.1 synthetic particles m−3 (non-fiber microplastics and synthetic fibers). The use of micro-spectroscopy methods is required to study smaller inhalable particles, benefiting from the use of silver membrane filters. Although these filters perform poorly during sample preparation, they can be stained with Nile Red and be used for pre-selection of suspected particles. Future inquiries require further method development to better assess smaller size fractions relevant for human exposure.