China News Network, March 3 -- On March 28, the Ministry of Ecology and Environment held a regular press conference in March. At the meeting, in response to the multiple rounds of sand and dust weather in the northern region since the Spring Festival this year, Liu Bingjiang, director of the Department of Atmospheric Environment of the Ministry of Ecology and Environment, pointed out that since the beginning of this year, there have been a total of 28 sand and dust weather in China, of which 3 were concentrated in March. Since March this year, there are two conditions for the more sand and dust weather, one is that the underlying surface is conducive to sand and dust activities, and the other is that the meteorological conditions are conducive to the transmission of sand and dust.
At the press conference, a reporter asked: Since the Spring Festival this year, there have been many rounds of sand and dust weather in the northern region, how much impact has it had on air quality? What are the main reasons?
Liu Bingjiang said that since the beginning of this century, China's dust weather has gradually decreased, and the high incidence period is still concentrated in March and May. Since the beginning of this year, there have been 3 sand-and-dust weather in China, 5 of which were concentrated in March. Since March, the sand and dust process has been slightly more than the same period of the previous year, two more than the same period of the decade, and two more than the same period of the decade. In particular, from March 6 to 4, the meteorological department classified it as a strong dust storm. According to visibility, the meteorological department divides sandstorms into five levels: extra strong sandstorms, strong sandstorms, sandstorms, blowing sand and floating dust.
The strong sandstorm that occurred from March 3 to 19 was the strongest and widest impact this year, affecting 23 provinces, autonomous regions and municipalities across the country, and the concentration of PM20.2 and PM5 in northern China reached serious pollution, and the peak PM10 in Zhangjiakou, Hebei Province exceeded 10,9000 micrograms per cubic meter. Affected by the sand and dust process, since the beginning of this year, a total of 140 cities across the country have experienced severe pollution of sand and dust, of which 131 cities have experienced serious pollution, both of which are the most in five years.
The number of days of excess caused by sand and dust nationwide reached 1533,590 days, an increase of 3 days year-on-year. As of March 26, the proportion of good days lost by 5.4 percentage points and the proportion of heavily polluted days increased by 1.2 percentage points due to sand and dust. The meteorological department said that the dust ended on the 24th, judging by visibility. But the impact on air quality is not over today, as of yesterday, there was still floating dust in many places, and PM10 still exceeded the standard.
Since March this year, there are two conditions for the reason for the more sand and dust weather, one is that the underlying surface is conducive to sand and dust activities. In 3, Mongolia's precipitation was less than the same period in 2022, and the vegetation cover of sandy sources was poor. Since March this year, the south of Mongolia and the northwest of China, the temperature is 20-3 degrees higher than the same period of normal temperature, especially in early March, there was an extremely rare warm weather, high temperature events in March are also felt, but the impact is far from being explained in a sentence. This warmer weather led to rapid melting of the frozen sand in the early stage, and at the same time, there was basically no precipitation process in the sand source, there was no snow cover on the surface, and a large area of the surface was exposed, which was conducive to sand and dust activities.
Second, the meteorological conditions are conducive to the transmission of sand and dust, this year Mongolia meteorological intensity is strong, cold air activity more, in the process of cold air moving south, strong winds swept up the sand, for the winch of dust particles into the high altitude to provide favorable meteorological conditions, under the action of the northwest air flow at high altitude, a large number of dust particles to the downstream transmission settlement, superimposed on the local sand source of Inner Mongolia, affecting the northern region of China.
For Beijing, there are two sand and dust transmission paths, one is the western part of China and the other is the south-central part of Mongolia. Among them, the air flow from the west direction is transmitted to Beijing, which is basically based on floating dust, and there will be no sandstorms; Sand and dust in the south-central part of Mongolia have the greatest impact, because the transmission path is relatively short and the air flow is stronger, which causes heavier pollution.
According to the statistics of researchers, in the past ten years, the number of sandstorms in the Gobi region of Mongolia has increased by four times compared with the 20s of the 60th century. In spring (April-May) this year, the precipitation in the sand source areas from southern Mongolia to central and western Inner Mongolia was less than that in the same period of the year, and the temperature was higher than the same period of the year, and there was a periodic southward influence of Mongolian cyclones, which was conducive to the formation of sand and dust weather process. It is expected that the number of sand and dust processes in northern China is more than the same period in the past decade, which means that this year is a big year of sand and dust.
Liu Bingjiang pointed out that in the future, the Ministry of Ecology and Environment will work with the meteorological department to strengthen air quality forecasting, predict that sand and dust may appear, and release information in time to remind the public to do a good job in health protection.