A new study conducted by the Department of Meteorology and Geophysics at the University of Vienna challenges many current beliefs about the source of airborne microplastics.
In previous years, it was thought that most microplastics originate from the ocean, and this assumption has been disproved, based on a study published in the journal Nature which says that land-based sources contribute significantly more particles to the atmosphere than sources in the oceans. The study compared a total of 2,782 samples of atmospheric data collected from around the world and advanced transport models to indicate that land-based sources contribute about 20 times more microplastics to the atmosphere than the oceans.
The new findings demonstrate that it is necessary to develop accurate data on the amounts of particles present in the atmosphere from various sources and the wear and tear of transportation network surfaces to fully understand how these synthetic products move through the Earth’s atmosphere.
Where do airborne microplastics actually originate?
According to the University of Vienna, the research was conducted by Ioana Evangelou, Silvia Bucci, and Andreas Stoll, who used an extensive database of 2,782 air samples collected from all over the world, through which they were able to determine the true source of these particles found throughout the environment.
The findings represent a paradigm shift in environmental science and indicate that, unlike in the past, when ocean spray was considered a major source of atmospheric microplastics, terrestrial sources (primarily from road tire wear and shedding of synthetic textile fibres) are now the major contributors to atmospheric microplastics.
Given this new information, the researchers conclude that Earth’s human-dominated environment produces 20 times more microplastics than the oceans, changing our understanding of plastic pollution around the world.
How new data has improved atmospheric modeling
An important element of this study involved a careful comparison between real-world atmospheric observations and results from existing transport models. The research team found that previous modeling efforts have consistently overestimated how widespread microplastic particles are, often by several orders of magnitude, both in the air and when deposited on the Earth’s surface. By identifying this large gap between theoretical predictions and experimental data, the team was able to recalibrate their models to account for disparities between land and ocean emissions profiles, as observed in research published in the journal Nature.
This technical modification successfully corrects old errors, providing a more accurate and scientifically grounded representation of how these pollutants are distributed through the planet’s atmosphere.
Remaining uncertainties in the distribution of microplastics
Despite the major advances in this work, lead author Andreas Stoll admits that there are still significant uncertainties, especially in how precisely we know the size distribution of airborne particles.
While the majority of the particle count came from land-based sources, the researchers pointed out a surprising exception: the total mass of particles emitted is greater over the ocean because oceanic particles tend to be larger than land-derived particles.
The research team clearly states that there is a continuing need to improve data collection methods and improve methods for separating contributions from specific sources (for example, automobiles versus different types of industrial emissions) to improve estimates of emissions from individual sources, as well as to gain a clearer understanding of the long-term impact on the environment.