Plastic pollution is an inescapable problem in our modern world. You may be surprised to learn that plastic does breakdown eventually; but the threat of it accumulating in landfills and in the oceans isn’t where the discussion should end. As it sits, it starts releasing particles that are called “microplastics.” Microplastics are then released into the very air we breathe—and a recent assessment shows that London is leading as the world’s biggest source of airborne microplastics, beating out even cities like Paris, Hamburg, and Dongguan, China.
Microplastics break down into either fibrous or non-fibrous particles that are small enough to be inhaled. These microplastics are swept along in the wind and can remain suspended for either days or weeks in the air before they are processed by precipitation. The microplastics can remain in the atmosphere and then become deposited into the air we breathe or into the oceans, where they can actually become re-aerated by oxygen in waves and bubbles and be released back into the air.
The study, published in the March edition of Environmental International, determined that the levels of microplastics in the urban environment of London were greater than previously speculated. Other urban centers such as Dongguan, China; Paris, France; and Hamburg, Germany were compared through analysis of the atmospheric fallout caused by microplastics. Dongguan and London are comparable in population size.
It stands to reason that the levels of microplastics would be greater in urban areas, but microplastics have also been found in remote samples of snow taken from the Arctic and the Swiss Alps. Though the levels of microplastics found in the remote regions are lesser than those found in urban areas, it represents a huge impact on the environment. The fallout measured in the remote areas are believed to be transported aerially by wind deflation up to 95 km in distance.
Despite Paris having a more densely populated city center than the other cities studied, the level of airborne microplastics did not correlate to the amount of people in any given area. Instead, Paris and Dongguan, China shared similar levels of pollution.
The fibrous particles were polymers such as polyester, polyurethane, PA, and polyacrylonitrile (PAN)—all commonly found in synthetic clothing, textiles, and upholstery.
The non-fibrous particles were composed of fragments, granules, films, and foams. The non-fibrous particles were identified as synthetic polymers used every day, consisting of polystyrene, PET, PP, PUR, PE, PVC (polyvinylchloride), polymerized petroleum resin, and acrylic polymer. Most of the non-fibrous particles were from PS (from which Styrofoam is made).
In London, fibrous microplastics traveled further than the non-fibrous particles due to their size and velocities. Ninety-two percent of the particles found were fibrous, and it is believed that it is mainly from wearing textiles and washing synthetic materials in washing machines.
More research is needed to understand where the airborne non-fibrous microplastics are originating, whether it be from tire use, degrading plastic bags, thermal insulations, or packing material. The study only focused on microplastics of a particular size; but the study’s authors point out there could be many, many more smaller particles that have not been studied yet.
The consequences of airborne particulate matter should not be underestimated. With the textile industry continuing to focus on synthetic materials and an expected increase in textile manufacturing’s use of plastics at a growing rate of 4% per year—we should be aware of the consequences to our health. Looking for natural fiber clothing (such as cotton and linen) and avoiding the “fast fashion” trend of cheaply made, synthetic material that is derived from plastic should be a public consideration for global human health.
Wright, S.L., et al. “Atmospheric Microplastic Deposition in an Urban Environment and an Evaluation of Transport.” Environment International, vol. 136, Mar. 2020, doi:https://doi.org/10.1016/j.envint.2019.105411.