Microplastics (MPs) are significant pollutants from urban activities, affecting water, air, and soil due to inadequate waste management. This thesis investigates MP sources, pathways, and removal efficiencies in urban environments, focusing on wastewater, road dust, and air.

The first study tracks MPs in sewerage systems, identifying industrial laundry facilities and domestic wastewater as major sources, with high concentrations of polyester fibers. The second study examines MPs in road dust and spider webs, revealing higher concentrations indoors and prevalent polyester fibers in urban air. The third study assesses a modern wastewater treatment plant, finding over 99% MP removal efficiency, with most MPs captured during primary settling stages.

The findings highlight the significant contributions of industrial and domestic activities to MP pollution, the pervasive nature of MPs in urban environments, and the effectiveness of modern wastewater treatment plants in mitigating MP pollution, although managing sludge remains a challenge. This research advances understanding of urban MP pollution and provides insights for developing effective strategies to combat this environmental threat.

For a copy of the thesis, please email inst.build.phd@build.aau.dk.