Mt Fuji, Meizan of aerological science

Microplastics detected for the first time in mountaintop clouds

Researchers from Waseda and other Japanese universities have found fine particles of plastic – microplastics – in clouds, reports the Guardian. This study may be the first to have sampled clouds for this form of environmental pollution.

Using “string-type passive cloud collectors”, the scientists sniffed the air from the tops of Mt Fuji (3,778 metres) and Mt Ōyama (1,252 metres) in the nearby Tanzawa range, both mountains that figure prominently in Japan’s most famous mountain book. Samples were also collected at Tarōbō (1,302 metres), on Mt Fuji’s lower slopes.

The researchers then looked at wind trajectories to work out where the plastic particles came from. As you’d expect, the summit of Mt Fuji attracts a superior range of pollutants. This may be because the winds that blow over Ōyama and Tarōbō come mainly from China, while the top of Mt Fuji also receives airborne tribute from Southeast Asia.

The aerologists follow in a lengthy tradition. They collected their high-altitude samples at the Mount Fuji Research Station. This comprises the buildings of the old weather station, which a non-profit organisation repurposed for summer-only scientific observations in 2007. 

But the weather station itself could trace its origins back to the winter of 1895, when Nonaka Itaru and his wife Chiyoko held out for more than two months in a small hut, making weather observations at the very highest point of Mt Fuji.

In those days, of course, the clouds were entirely free of fine particles of plastic.

References

Yize Wang, Hiroshi Okochi, Yuto Tani, Hiroshi Hayami, Yukiya Minami, Naoya Katsumi, Masaki Takeuchi, Atsuyuki Sorimachi, Yusuke Fujii, Mizuo Kajino, Kouji Adachi, Yasuhiro Ishihara, Yoko Iwamoto and Yasuhiro Niida, “Airborne hydrophilic microplastics in cloud water at high altitudes and their role in cloud formation”, Environmental Chemistry Letters, August 2023.