A study from Waseda University in Japan has highlighted the widespread problem of airborne microplastics (AMPs), revealing their impact on cloud formation and potential factors that may accelerate global warming. Plastic particles smaller than 5 mm are called "microplastics". These tiny plastic particles are often found in industrial wastewater or formed from the degradation of larger plastic waste.
Research shows that both humans and animals ingest or inhale large amounts of microplastics, and microplastics have been detected in multiple organs including the lungs, heart, blood, placenta and feces. Tens of millions of tons of these plastic fragments end up in the ocean, where they are released in ocean water and enter the atmosphere. This means that microplastics may have become a significant part of the clouds, contaminating almost everything we eat and drink through "plastic rain". While most research on microplastics has focused on aquatic ecosystems, few have examined the impact of microplastics as "airborne particles" on cloud formation and climate change.
Microplastics in the air: Impact on health and climate
In a new study led by Waseda University Professor Hiroshi Okochi, a team of Japanese researchers explored the pathways by which airborne microplastics (AMPs) travel through the biosphere and their adverse effects on human health and climate. Their research was recently published in the journal Environmental Chemistry Letters, with co-authors including Yize Wang of Waseda University and Yasuhiro Niida of PerkinElmer Japan Ltd. Written by Yasuhiro Niida of Ltd. "Microplastics in the free troposphere can be transported and cause global pollution. If the problem of 'plastic air pollution' is not actively addressed, climate change and ecological risks may become a reality, causing irreversible and serious environmental damage in the future," Okochi explained.
AMPs have been detected in cloud water samples from mountaintops in Japan, confirming that they play a key role in the rapid formation of clouds, according to results of a new study. Image credit: Hiroshi Okochi, Waseda University
To study the role of these tiny plastic particles in the troposphere and atmospheric boundary layer, the research team collected cloud water from the top of Mount Fuji, the southeastern foothills of Mount Fuji (Tarobo), and the top of Oyama, with altitudes ranging from 1,300 to 3,776 meters above sea level. Using advanced imaging techniques such as attenuated total reflection imaging and micro-Fourier transform infrared spectroscopy (µFTIRATR imaging), the researchers determined the presence of microplastics in cloud water and examined their physical and chemical properties.
The researchers found nine different types of polymers and one type of rubber among the microplastics they detected. It is worth noting that most of the polypropylene detected in the samples was degraded and carried carbonyl (C=O) and/or hydroxyl (OH) groups. The Feret diameters of these AMPs range from 7.1-94.6µm, the smallest in the free troposphere. In addition, there are large amounts of hydrophilic (water-loving) polymers present in the cloud water, suggesting that they were removed as "cloud condensation nuclei." These findings confirm that AMPs play a key role in the rapid formation of clouds, which may ultimately affect the entire climate.
The accumulation of AMPs in the atmosphere (especially in polar regions) may lead to major changes in the earth's ecological balance, leading to severe loss of biodiversity. Okochi concluded: "Due to intense ultraviolet radiation, AMPs degrade much faster in the upper atmosphere than at the ground level, and this degradation releases greenhouse gases that contribute to global warming. Therefore, the results of this study can be used to consider the impact of AMPs in future global warming predictions."