Characterisation and Source Identification of Atmosphericmicro/nanoplastics in Hong Kong

Airborne micro- and nanoplastic (AMNP) pollution is ubiquitous in the environment, and its abundance and persistence in the atmosphere have raised global concern. Transport and the changing interface of micro- and nanoplastics play an essential role in linking their sources and sinks within the planetary system. In this study, an airborne micro- and nanoplastic measurement campaign was conducted using our newly developed active samplers to investigate the unique sources and interface changes of AMNPs in Hong Kong. These include tyre wear from take-off and landing operations at Hong Kong International Airport (HKIA). Two distinct sampling sites from Tung Chung for airport-related AMNPs were selected. Seasonal measurements were arranged to capture both seasonal and event-based variations in AMNP concentrations. All collected samples underwent Micro-FTIR and PY-GC-MS analyses to determine the physical properties (e.g., size, shape, morphology) and chemical composition of AMNPs, and were subsequently applied to source and receptor analyses. To the best of our knowledge, this is the first survey of atmospheric AMNPs in Hong Kong, providing essential information on background AMNP levels.