Microplastics have infiltrated almost every corner of the planet, posing serious threats to various ecosystems. Just recently, their presence in clouds has been confirmed, possibly contaminating food and worsening global warming.
Worldwide Distribution of Microplastics
Microplastics are plastic particles that measure under 5 millimeters. They come from personal care products, synthetic car tires, textiles, industrial effluent, and other sources. Since decomposing takes centuries, they have become a growing threat to most ecosystems as humans continue using and discarding plastic.
They have recently been discovered in the snow in the Pyrenees mountains, Arctic sea ice, the Mariana Trench, and the peak of Mount Everest. Their transport mechanisms to different locations remain unclear since studies on airborne microplastic vehicles, in particular, are limited.
It has been confirmed that many microplastics are ingested or inhaled by humans and animals alike and have been found in multiple organs, such as the heart, blood, lungs, and placenta. Ten million tons of plastic bits end up in the ocean, are released with water vapor, and find their way into the atmosphere. It may become an essential component of clouds and contaminate almost everything we eat and drink through "plastic rainfall."
Alarming Presence in the Clouds
Studies have been conducted on microplastics in marine and terrestrial environments, but research on airborne microplastics has been limited. In Japan, a team of researchers led by Hiroshi Okochi of Waseda University focused on identifying microplastics in cloud water.
In this study, the scientists visited two mountains where they collected water from the mists that covered the peaks for several months. They examined 44 samples of water taken from clouds at the summit and foot of Mount Fuji and Mount Tanzawa-Oyama, which is located west of Yokohama in Kanagawa prefecture. Advanced imaging techniques and infrared spectrometry are then applied to the samples to determine their physical and chemical properties.
Based on their analysis, the researchers identified nine different types of polymers and one type of rubber in the airborne microplastics, ranging in size from 7.1 to 94.6 micrometers. They also discovered that each liter of tested cloud water contained 6.7 to 13.9 pieces of plastic.
According to the researchers, the presence of microplastics in clouds is especially concerning because some of the microplastics they found had molecular structures that can help in cloud seeding, spurring them to make ice or water. These particles also contribute to the formation of clouds, which can affect their cooling effect on Earth.
According to Okochi, if the issue of "plastic air pollution" is not addressed proactively, climate change and environmental risks may become a reality. It can even cause irreversible and serious ecological damage in the future. When these microplastics reach the upper atmosphere and get exposed to UV radiation from the Sun, they degrade and may contribute to greenhouse gases.
The research team plans to investigate the details of their findings further, as microplastics in the clouds can affect the climate and harm the human body.
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