Microplastics from packaging and plastic bottles are now finding it easy to trek to the depth of your own lungs, while you breathe your regular fresh air.
A recent study conducted by PNAS examined the sources of atmospheric microplastics that are increasing at an alarming rate of around 4% per year. The study discovered that India, Europe, Eastern Asia, the Middle East, and the United States are among the hotspots for terrestrial microplastic sources and accumulation. However, the greatest concentration of microplastics was estimated to be present above the oceans.
What are Microplastics?
Plastic is the most prevalent type of marine debris found in our ocean and Great Lakes. Plastic debris can come in all shapes and sizes, but those that are less than five millimeters in length (or about the size of a sesame seed) are called “microplastics.”
Microplastics come from a variety of sources, including from larger plastic debris that degrades into smaller and smaller pieces. In addition, microbeads, a type of microplastic, are very tiny pieces of manufactured polyethylene plastic that are added as exfoliants to health and beauty products, such as some cleansers and toothpaste.
These tiny particles easily pass through water filtration systems and end up in the ocean and Great Lakes, posing a potential threat to aquatic life.
Where is Atmospheric microplastics coming from
Results suggest that atmospheric microplastics in the western United States are primarily derived from secondary re-emission sources including roads (84%), the ocean (11%), and agricultural soil dust (5%).
While dust and agriculture sources for microplastics are more prevalent in northern Africa and Eurasia, microplastics from road traffic are a major contributor in “heavily populated regions” across the globe like India. Ocean sources of airborne plastic are present along the coasts, including the US West Coast, the Mediterranean, and southern Australia.
Using the best estimate of plastic sources and modeled transport pathways, most continents were net importers of plastics from the marine environment, underscoring the cumulative role of legacy pollution in the atmospheric burden of plastic.
This effort uses high-resolution spatial and temporal deposition data along with several hypothesized emission sources to constrain atmospheric plastic. Akin to global biogeochemical cycles, plastics now spiral around the globe with distinct atmospheric, oceanic, cryospheric, and terrestrial residence times.
Though advancements have been made in the manufacture of biodegradable polymers, research data suggest that extant nonbiodegradable polymers will continue to cycle through the earth’s systems. Due to limited observations and understanding of the source processes, there remain large uncertainties in the transport, deposition, and source attribution of microplastics. Thus, they prioritize future research directions for understanding the plastic cycle.