What are the hazards of sandstorms?

Sandstorm weather is a disastrous weather in northwest China and northern North China, which can cause houses to collapse, traffic power supply to be blocked or interrupted, fires, human and animal casualties and so on. It pollutes the natural environment, destroys the growth of crops and causes serious losses and great harm to the national economic construction and the safety of people's lives and property.

The hazards of sandstorms mainly include the following aspects:

1. Environmental pollution

When sandstorms occur, dust and floating dust carried by strong winds are everywhere, and the number of people passing through areas with air turbidity, choking nose and eyes, respiratory tract and other diseases increases. For example,1A serious sandstorm occurred in Jinchang on May 5, 993. The dust content in outdoor air is 10 16 mm/cm3, and the dust content in indoor air is 80 mm/cm3, which is 40 times higher than the national standard for dust content in living quarters.

4. Production and life are affected.

A lot of dust carried by sandstorm weather blocked the sun, and the weather was gloomy, which led to the decrease of solar radiation. A few hours to ten hours of poor visibility can easily make people feel depressed and reduce the efficiency of work and study. In light cases, a large number of livestock can be infected with respiratory and gastrointestinal diseases, and in severe cases, a large number of "spring-deficient" livestock will die, and fertile soil, seeds and seedlings in farmland will be scraped away. Sandstorm will also aggravate the wind erosion and desertification of the surface soil, cover thick dust on the leaves of plants, affect normal photosynthesis and cause crop yield reduction. Sandstorms also caused the temperature to drop sharply. The sky is like a parasol, and the ground becomes dark and cold in the shadow.

3. Loss of life and property.

1On May 5, 1993, a serious sandstorm occurred in Jinchang, Wuwei, Minqin and Baiyin, Gansu Province, which affected 2,535,500 mu of farmland, lost 42,800 trees, caused a direct economic loss of 236 million yuan, killed 85 people and seriously injured 153 people. On April 12, 2000, serious sandstorms occurred in Yongchang, Jinchang, Wuwei and Minqin. According to incomplete statistics, the direct economic losses in Jinchang and Wuwei alone amounted to15.34 million yuan.

65438+1On May 5, 1995, the dust fall of a serious sandstorm in Gansu Province was as high as1.2431×107t, which was equivalent to the output of the largest cement plant in Gansu Province in 15 years. 1April, 1998, the northwest 12 prefectures and states were hit by sandstorms, 46 10000 mu of crops were affected,1/0900 livestock died, 15600 people were affected, and direct economic losses were caused. The sandstorm affected the area from the east to the lower reaches of the Yangtze River, and the scope of influence was rare in history. The administrative office of Alashan League in Inner Mongolia reported in an urgent document that the League was harmed by sandstorm: 8~ 10 gale hit 12h, and the average concentration of environmental quality TSP was 62.4 mg m-3, which exceeded the national air quality standard by more than 200 times, and it lasted for a long time and had a wide range. According to local statistics, the direct economic loss (excluding land loss) caused by sandstorms for six consecutive days exceeded 1 100 million yuan.

4. Affect traffic safety.

Sandstorms that affect traffic safety (traffic accidents such as airplanes, trains and cars). ) often affect traffic safety, resulting in aircraft can not take off or land normally, cars, train cars break, stop or derail.

5. Harm to human health.

When people are exposed to dusty weather, dust containing various toxic chemicals and bacteria can enter the mouth, nose, eyes and ears through layers of protection. If the dust containing a lot of harmful substances is not cleaned in time, it will cause damage to these organs or bacteria will take these organs as invasion points, causing various diseases. High dust concentration in the atmosphere is easy to cause respiratory diseases. For example, sandstorm pneumoconiosis is an endemic disease caused by severe atmospheric dust in arid and semi-arid environments.

(6) Land degradation

There are two main hazards of black wind (especially strong sandstorm): one is wind, the other is sand; There are two hazards of strong winds: one is wind damage, and the other is scraping the ground.

Wind damage: strong winds destroy buildings, blow down or pull up tree stems, tear up farmers' plastic greenhouses and farmland plastic films, etc. In addition, April and May in northwest China are the time when cash crops such as melons, fruits, vegetables, beets and cotton emerge, cotyledons or true leaves grow, and fruit trees bloom, at this time, they are least resistant to sandstorms. Light leaves are covered with dust, which weakens photosynthesis, affects respiration and reduces crop yield; For example, the black wind on May 5, 1993/kloc-0 caused 85,000 pistils of fruit trees to be destroyed in northwest China, and 109400 shelterbelts and timber forests were broken or uprooted. In addition, the strong wind blew down the telephone poles, causing water and electricity cuts and affecting industrial and agricultural production. 1On May 5, 993, the black wind caused power failure and water cut, and Jinchang Jinchuan Company alone caused economic losses of 83 million yuan.

Scraping: When strong wind acts on loose soil in arid areas, it will scrape off a layer of topsoil, which is called wind erosion. For example,1May 5, 1993, the average wind erosion depth of black wind 10 cm (up to 50 cm), that is, an average of 60 to 70 cubic meters of fertile topsoil per mu was blown away by the wind. In fact, strong winds not only blow away the fine clay and organic matter in the soil, but also pile up the sand in the soil, which greatly reduces the fertility of the soil. In addition, the strong wind with sand will wear off a layer of buildings and crops, which is called abrasion and also a disaster.

Hazard of sand: The hazard of sand is mainly sand burial. As mentioned above, in narrow pipelines, windward and uplifted terrain, due to high wind speed, the wind-blown sand hazard is mainly wind erosion, while in leeward depressions and other terrain with low wind speed, the wind-blown sand hazard is mainly sand burial. Such as1where sand burial occurred in the black wind on May 5, 993, the average thickness of sand burial was 20 cm, and the thickest part reached1.2 m.

(1) Strong wind: Strong wind with fine dust damages buildings and public facilities.

Causing human and animal casualties.

⑵ Sand burial: Farmland, channels, cottages, railways, grasslands, etc. are buried by a large number of quicksand in the form of quicksand, especially posing a serious threat to transportation.

⑶ Soil wind erosion: The dust source and affected area of each sandstorm will be harmed by wind erosion in different degrees, and the depth of wind erosion can reach 1 ~ 10 cm. It is estimated that the annual loss of soil fine particles caused by sandstorms in China is as high as 106 ~ 107 tons, most of which are below 10 micron, which seriously damages the land productivity of farmland and grassland in the source area.

⑷ Air pollution: In the source area and influence area of sandstorm, the inhalable particulate matter (TSP) in the atmosphere increases, and air pollution intensifies. Taking 1993 "5.5" sandstorm as an example, the outdoor air TSP concentration in Jinchang, Gansu Province reached 10 16 mg/m3, and the indoor air TSP concentration was 80 mg/m3, exceeding the standard by 40 times. From March to April, 2000, Beijing was affected by sandstorms, and the number of days when the air pollution index reached Grade 4 or above reached 10, which also affected many cities in eastern China. From March 24th to 30th, the daily pollution index of Nanjing, Hangzhou and other cities 18 exceeded Grade IV.