It is raining plastic: 74 tonnes of microplastics fell from the air on Auckland in 2020

Tinier particles that are inhaled easily were found in higher quantities

By DTE Staff
Published: Wednesday 14 December 2022
Airborne microplastics: Large quatities of microplastics are deposited on Auckland every day, raising concerns
Photo: iStock Photo: iStock

With our every breath, we may be inhaling substantial quantities of microplastics that eventually flow into our blood and accumulate on our organs, according to a new study. 

As much as 74 tonnes of microplastics fell from the air and settled on rooftops, gardens and other surfaces in Auckland, New Zealand in 2020, the study published December 12, 2022 in the journal Environmental Science & Technology found. The volume is equivalent to three million plastic bottles, it added.

These tiny pieces of plastic that are less than 5 millimetres in length have already invaded our food chains and have been found in veins, and this new mode of transmission is raising new health concerns. 

The smallest particles can enter blood streams and collect in organs like the liver and brain. 

Scientists have been discussing the possibility that microplastic mists and clouds exist in the atmosphere but this is the first study to quantify the magnitude of the problem. 

The researchers from the University of Auckland used a coloured dye that emits light under certain conditions and a heat interaction to identify the microplastics because they are invisible to the naked eye. The study was carried over nine weeks. 

On an average, 4,885 airborne plastic particles had accumulated in one square metre in one day, they found. 

The levels found in Auckland’s air were many times higher than recorded in London, Hamburg and Paris in recent years because scientists in the new study used sophisticated chemical methods to find and analyse particles as small as 0.01 of a millimetre, according to a story in Science Daily.

The size of the particles was also a concern as the tinier particles were higher in quantity, according to the new report. The smaller the particles, the more harmful it is for human health. 

Microplastics are formed during making of plastic products and breaking down of large plastics due to weathering and ageing. Plastics are added to the environment during washing of synthetic clothes, fragments shed by car tyres and washed by rain into the ocean, bottles floating down rivers, among others, according to ScienceDaily. 

The microplastics found in the new study came from a variety of sources, the authors noted. “In Auckland, polyethylene — often used in packaging materials — was the most-detected substance, followed by polycarbonate, a type of plastic typically used in electrical and electronic applications,” news outlet Bloomberg reported. 

Finally, the researchers noted that breaking waves of seas may be transporting the microplastics far and wide. This can help understand how the microplastics spread through the atmosphere, said Joel Rindelaub, one of the authors of the study and researcher at the School of Chemical Sciences, University of Auckland. 

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