Азия шаңы және дақылды жел құбылысы

East Asian meteorological phenomenon

Asian Dust (also yellow dust, yellow sand, yellow wind or China dust storms) is a meteorological phenomenon that affects much of East Asia year round and especially during the spring months. The dust originates in the deserts of China, Mongolia, and Kazakhstan, where high speed surface winds and intense dust storms kick up dense clouds of fine, dry soil particles. These clouds are then carried eastward by prevailing winds and pass over China, North and South Korea, and Japan, as well as parts of the Russian Far East. Sometimes, the airborne particulates are carried much further, in significant concentrations which affect air quality as far east as the United States. Since the turn of the 21st century, coinciding with the rapid industrialization of China, yellow dust has become a serious health problem due to the increase of industrial pollutants contained in the dust. Intensified desertification due to deforestation has been causing longer and more frequent occurrences. The issue has been exacerbated as the Aral Sea of Kazakhstan and Uzbekistan has largely dried up. This started in the 1960s with the diversion of the Amu River and Syr River, as part of a Soviet agricultural program to irrigate Central Asian deserts, mainly for cotton plantations.

Some of the earliest written records of dust storm activity are recorded in ancient Chinese literature. It is believed that the earliest Chinese dust storm record was found in the Zhu Shu Ji Nian (Chinese: 竹书纪年; English: the Bamboo Annals). The record said: in the fifth year of Di Xin (1150 BC, Di Xin was the Era Name of the King Di Xin of Shang Dynasty), it rained dust at Bo (Bo is a place in Henan Province in China; in Classical Chinese: 帝辛五年，雨土于亳). The first known record of an Asian Dust event in Korea was in 174 AD during the Silla Dynasty. The dust was known as "Uto (우토, 雨土)", meaning 'Raining Dirt/Earth', and was believed at the time to be the result of an angry god sending down dust instead of rain or snow. Specific records referring to Asian Dust events in Korea also exist from the Baekje, Goguryeo, and Joseon periods.

An analysis of Asian Dust clouds conducted in China in 2001 found that they contain high concentrations of silicon (24–32%), aluminium (5.9–7.4%), calcium (6.2–12%), and iron. Numerous toxic substances were also found, including mercury and cadmium from coal burning. People further from the source of the dust are more often exposed to nearly invisible, fine dust particles that they can unknowingly inhale deep into their lungs, as coarse dust is too big to be deeply inhaled. Research done in 2014 found that China dust consists of fine dust and ultrafine dust particles. Fine dust consists of fine particulate matter (PM). Particles smaller than 10 μm in diameter are classified as fine PM (PM10), while particles smaller than 2.5 μm in diameter are classified as ultrafine PM (PM2.5). Both fine and ultrafine dust particles impose dangers to health. Fine dust particles are small enough to penetrate deep into the lung alveoli. Ultrafine dust particles are so small that they also penetrate into the blood or lymphatic system through the lungs. Once in the bloodstream, ultrafine particles can even reach the brain or fetal organs. High population growth in China has led to increasing demand for wood for housing and furniture as well as for firewood for cooking and heating. This increase in demand for wood (and firewood) has led to over cutting of timber. At the same time, there has been an increase in demand for food, which has led to soil erosion due to overgrazing of arable land. For example, the northern part of Shaanxi Province and the Haixi area of Gansu Province was once a deep forest region, but the region now only has treeless mountains. Historically "because peasant farmers continue[d] to rely on low technology agricultural techniques, they [had] to exploit virgin land to sustain a continually growing population. There is also evidence that days with Asian Dust coupled with smog lead to increased mortality due to respiratory and cardiovascular diseases among inhabitants in affected regions. The OECD predicted 1,069 premature deaths per million directly attributable to worsening air pollution in South Korea by 2060.

Due to the concerning health effects, residents of affected regions have reduced their exposure to Asian dust by refraining from outdoor activities. Despite the temperature rise to warm levels during spring season, popular outdoor destinations are empty on days with yellow dust advisory or warning. According to a survey in 2019, 97% of Koreans reported that they suffered from physical or mental distress due to Asian dust including fine dust during the time of the survey. Since children are among the most vulnerable to fine dust particles, affected countries have come up with measures to minimize the detrimental effects on children; in 2017, South Korea's Ministry of Education have required all primary to high schools to create indoor spaces for sports and outdoor activities. Similar efforts are arising in professional sports. In 2019, the Korea Baseball Organization changed its regulations to cancel or suspend professional games during a severe fine dust warning. As a result, during spring, when Asian dust levels are at the highest, airlines with aircraft in the affected region spend time and money to wash dust off their aircraft. Washing dust off a single B747 jumbo jet typically takes 6000 liters of water and eight hours with nine people working. The sale of dryers also surged 67% during the same period as outdoor air drying no longer became an option. This accounts for between 0.6% and 1.0% of the nation's GDP and US$81.48 and $152.52 per nation's resident.

Asian dust is a historically significant contributor of soil nutrients for some North Pacific islands, including Hawaii.

Asian dust is an example of a negative externality on society. Policy choices that favor rapid industrialization and deforestation in China, Mongolia, and other Central Asian regions impose social costs on Eastern countries, such as Korea, Japan, and Russia in the Far East. The main cause of deforestation is extensive logging. According to an analysis on data from Korea Meteorological Administration (KMA), the average number of days with Asian dust in a given year was about two in the 1960s. However, this number has increased to 11 in 2000s. In 1960s and 1970s, each decade had 3 years that were Asian dust free. However, starting from 2000s, there has not been a single year without Asian dust. Asian dust, in combination with smog and general air pollution, has become so severe that it became a political issue in the South Korean presidential election in 2017. All three main candidates of the election—Moon Jae in, Ahn Cheol soo, and Hong Joon pyo—promised to take measures to alleviate these growing national air pollution problems. These figures are probably vastly underestimated, as they only take into account direct effects, without including medical, pollution, and other secondary effects, as well as effects to neighboring nations. El Niño also plays a role in Asian dust storms, because winter ice can keep dust from sweeping off the land.