UK researchers have found that microplastics, including those from textiles, are present in the air in London at higher abundances than any other major city, including Dongguan, China.
The researchers from King’s College carried out the study in London to determine what people within the city might be exposed to and from where. Published in Environmental International, they found fibrous microplastics, ie from the weardown of plastic textiles including clothing, accounted for 92% of all microplastics found during the sampling.
The study also found microplastics were present in every sample taken in London and greater than previously reported by any other study, with the levels higher than Dongguan, China and Paris, France and Hamburg, Germany.
Researchers say the microplastics can become airborne and travel as far as 95km by the wind, however, local sources have a greater influence on deposition in central London.
Their findings indicate that cities are a likely source of microplastics to the wider environment with the weather and meteorological patterns having little influence on their abundance in this urban environment.
“We found some of the highest reported levels of microplastics in atmospheric dust, with local sources appearing influential,” said lead author Dr Stephanie Wright, UKRI Rutherford Fellow in the School of Population Health & Environmental Sciences at King’s. “Fibres were the most abundant for the size range we looked at, mirroring the marine environment. From where microplastics are emitted and for how long they are airborne remain unknown but are key for understanding long-range transport potential to the wider environment. An important next step in predicting risk is to estimate human exposure to airborne microplastics.”
Microplastics are made through the fragmentation or scuffing of larger pieces of plastic, such as from degraded plastic litter or fibres from synthetic clothing. They are also purposefully manufactured for a range of applications, although the EU has proposed to restrict the use of intentionally added microplastics in products. There may be other sources of microplastics which have not been discovered yet.
Researchers used a rain gauge with a funnelled surface to collect atmospheric deposition (dust naturally settling out of the atmosphere) in central London during winter 2018. This was filtered and analysed using a specialist instrument which detects unique chemical ‘fingerprints’ of the particles to identify their composition.
The authors are now looking at longer-term patterns of microplastic deposition and will begin to look at spatial distribution, comparing different types of environments such as rural, urban, coastal and industrial, to understand its entry to the wider environment. They are also quantifying microplastics in size fractions capable of depositing in the human airway, in order to begin to understand exposure via the air and the consequences for human health.