WHERE MICROPLASTICS MEET PEDESTRIANS: EVALUATING GREEN INFRASTRUCTURES ROLE IN REDUCING TRANSPORT-RELATED POLLUTION

As cities grapple with the invisible threat of airborne microplastics (MPs), non-exhaust emissions, especially tire wear particles (TWPs)—are becoming significant contributors to urban air pollution. While vehicular emissions regulations have successfully reduced exhaust pollutants, non-exhaust emissions remain a significant challenge. Urban Green infrastructure (UGI), often valued for its aesthetic and ecological functions, has yet to be fully explored for its potential to reduce MP exposure. This study investigates the role of a Thuja occidentalis hedge in Kaunas, Lithuania, as a natural barrier against traffic-induced MPs. Over a year-long sampling campaign (June 2023–April 2024), passive deposition was conducted at four distances from the hedge (-1 m, 0 m, +1 m, +2 m), with additional sampling in the hedge’s absence to establish an experimental-control comparison. Optical microscope analysis revealed distinct size and shape distributions, while micro-FTIR spectroscopy confirmed the dominant presence of PE and PP in the collected MPs. MP concentrations peaked in spring (5.95 particles/cm²/day) at the roadside (-1m). Most MPs were fragments (91.38%), with polyethylene (PE) as the dominant polymer (43.04%), followed by polypropylene (PP) (15.11%). The hedge demonstrated remarkable efficiency in capturing MPs, particularly in summer, with removal rates of 64.5% for total MPs, 64.3% for fragments, and 71.4% for fibers. The hedge effectively trapped larger MPs (>50 µm). This study highlights the untapped potential of UGI as an active defender against transport-related MP pollution in the urban environment, advocating for its strategic incorporation into urban design to enhance public health protection.