Microplastic pollution is an emerging area of research globally. The ability of microplastics to be airborne allows particles to reach remote and sensitive environments previously thought untouched by plastic pollution. Research on airborne microplastics in the Southern Hemisphere is currently lacking. There is a need to identify microplastic abundance in remote regions to understand the wider implications of their dispersal on ecosystem health and atmospheric processes. This research aims to address the gap in our knowledge of remote airborne microplastics in the Southern Hemisphere.

Two field studies were undertaken to assess the presence of airborne microplastics in Antarctica and New Zealand. Samples were collected from sites across the Ross Island region of Antarctica and a remote site in the Mackenzie District, New Zealand. Particles of interest were isolated in the laboratory prior to analysis by stereomicroscope and micro-Fourier transform infrared spectroscopy. Microplastics were characterised by polymer type, morphotype, colour and size.

Microplastics were identified in all Antarctic snowfall samples at an average concentration of 29.4 particles L⁻¹ and maximum concentrations of 85 particles L⁻¹. Potential sources from both local and long-range transport were analysed, with local sources from research stations being identified as a main source of microplastics into this remote region. New Zealand samples identified low deposition rates at an average rate of 0.004 particles m⁻² day⁻¹. Both studies identified PET as the most common polymer and fibres as the most common morphotype.

This research adds to the growing body of knowledge on anthropogenic influences on remote regions of the world. This thesis describes the negative impacts of microplastics on ecosystem health and function, human health, and their potential to influence atmospheric processes. The prevalence of microplastics in the regions investigated highlight the need to further our knowledge and take necessary actions to limit the negative impacts of microplastics.