An observation of yellow sand in Tokyo has been reported for two consecutive days starting from Wednesday the 12th to Thursday the 13th. The yellow sand was blown over a wide area from Kyushu to Hokkaido, and the phenomenon was observed in 31 prefectures. The concentration of yellow sand was considerably low on Friday the 14th, but it was still observed in Tokyo and Nagoya. The next yellow sand is expected to arrive from the west as early as Sunday 16th. It is advisable to take precautions if prone to allergies or have respiratory problems. The article discusses the areas affected and necessary precautions.
Observation of yellow sand in Tokyo for 2 consecutive days.
April 14, 2023 11:03
In the Japanese archipelago, from Wednesday the 12th to Thursday the 13th, kosa was blown over a wide area from Kyushu to Hokkaido, and was observed in 31 prefectures. On Friday the 14th, the area was small and the concentration was low, but it was observed in Tokyo and Nagoya. After this, the yellow sand will temporarily leave the archipelago, but the next yellow sand is expected to fly in from the west as early as Sunday, the 16th. What are the affected areas and precautions?
“Yellow sand” observed in 31 prefectures
In the Japanese archipelago, from Wednesday the 12th to Thursday the 13th, yellow sand flew over a wide range from Kyushu to Hokkaido, and was observed in 31 prefectures. It will be the first time in two years since May 8, 2021 that yellow sand will be observed in Tokyo, and the first observation in April since 2007 in 16 years. In various places, the sky turned yellow and visibility became poor, cars and laundry became dirty, and allergic symptoms worsened.
Today, Friday the 14th, the area of yellow sand became narrower and the concentration was low, but in the early morning of the 14th, yellow sand was observed in Tokyo and Nagoya. It was observed for two consecutive days in Tokyo and for three consecutive days in Nagoya. Visibility (horizontal line of sight) is 10 kilometers or more, and the concentration of yellow sand is considerably thin.
In the afternoon, the yellow sand area will become narrower, and it is expected to calm down in various places at night. However, if you are prone to allergies or have respiratory problems, it is safe to take measures such as wearing a mask and glasses when going out just in case.
“Yellow sand” comes flying again from Sunday 16th
It’s a fleeting moment to be relieved. As of Friday the 14th, a large amount of yellow sand is being blown up again in the continental direction, and it is expected to return to Japan on Sunday the day after tomorrow, the 16th.
On Sunday the 16th, from Wednesday the 12th to Thursday the 13th, the upper wind (westerly wind) meanders southward, so it is expected to fly mainly in western and eastern Japan, and also affect Okinawa. If observed in Naha, it will be the first since March 6, 2022.
This spring, there is little precipitation in mainland China and the air is dry. As low pressure develops, it is likely that sand will be blown up, so caution will be required in the future.
The messenger of spring “Kosa” is the most abundant in April
“Yellow sand” is a phenomenon in arid or semi-arid areas such as deserts where soil and mineral particles are blown up several thousand meters by the wind and carried by westerly winds, floating and falling into the atmosphere.
In the past, kosa was understood to be a natural phenomenon, but in recent years, its frequency and damage have increased, and it has been pointed out that it is related to land degradation due to rapidly spreading overgrazing and agricultural land conversion. I’m here.
In Japan, they often fly from March to early spring, and tend to decrease after June.
*From “Japan Meteorological Agency | Changes over time in the number of days observed for yellow sand”
particle size
Most of the yellow sand particles are about 4 μm in size. Pollen particles are about 30 μm in diameter, and PM2.5 are about 2.5 μm or less in diameter.
For example, a hair is about 70 μm in diameter, so it would be difficult to observe the particles themselves with the naked eye. In addition, some of the yellow sand particles have a diameter of 2.5 μm or less, and it seems that the concentration of PM2.5 may increase with the arrival of yellow sand.
* From “Ministry of the Environment’s Frequently Asked Questions about PM2.5”
Points to prevent health hazards caused by yellow sand
There are three points to prevent the effects of kosa on health.
① Check the latest information on a daily basis and grasp the forecast of the arrival of yellow sand.
② When yellow dust is flying, you can expect to reduce the amount of yellow sand that you inhale by refraining from going out unnecessarily and non-urgently. In particular, it is best to avoid long periods of vigorous outdoor exercise when high concentrations of yellow sand are blowing. It is important for people with respiratory or circulatory disease, children, and the elderly to act more carefully according to their physical condition. Dry your laundry and futon indoors as much as possible.
③ When kosa is flying, wearing a mask (non-woven mask, etc.) can be expected to have a certain degree of preventive effect. When wearing a mask, choose one that fits the size of your face so that air does not leak.
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Stay alert and take necessary precautions against the yellow sand phenomenon, which is increasingly becoming a concern for many countries. Monitoring the latest information and forecasts, refraining from going out unnecessarily during yellow sand occurrences, and wearing masks can prevent health hazards caused by the phenomenon. Additionally, educating yourself and taking steps to reduce environmental degradation can help decrease the frequency and damage caused by yellow sand. Stay safe and informed during this season.