Quantifying Atmospheric Deposition of Microplastics in Urban and Suburban O'ahu

Abstract

Airborne microplastic pollution in the Hawaiian Islands can have several sources: atmospheric, oceanic, or urban. Airborne microplastic particles settle out of the atmosphere, landing in our homes, on vegetation, and all around us, where all forms of life can inhale or consume them. The primary goal of this research project is to determine the largest source of microplastic particles on Oʻahu and the impact of wind speed, wind direction, and precipitation on microplastic fallout rates. The information learned throughout the process of this research project will aid in providing the public with knowledge they can use to adjust their daily lives to limit microplastic pollution exposure and help to determine future research needs and focus future research efforts on microplastic fallout in Hawaiʻi. To determine the most significant factors for microplastic deposition, measurements of microplastic particles in two unique locations, urban and suburban, were conducted to determine the areas of Oʻahu most susceptible to atmospheric microplastic pollution. Wind speed from National Weather Service weather stations was used to contextualize the pollution measurements. While a study of this type has never been done in Hawaiʻi, prior research from other locations shows that urban centers have high fallout rates, following high wind conditions (Jahandari, 2023). Results from this project show similar results for Hawaiʻi. The data suggest that greater wind speed facilitates the dispersal of microplastics, allowing higher concentrations to accumulate in both Urban and Suburban environments. However, suburban areas have significantly lower rates of microplastic deposition regardless of weather patterns.