(1) Main hazards of sandstorms
Strong winds carrying fine sand dust destroyed buildings and public facilities, causing casualties of people and animals.Sand burial is caused by wind-sand flow, which buries farmland, channels, villages, railways, grasslands and so on, and poses a serious threat to transportation.The source and affected area of each sand-dust storm will be damaged by wind erosion to varying degrees, the depth of wind erosion can reach 1 to 10 cm.It is estimated that the loss of soil fine matter caused by dust storms is as high as 106 to 107 tons per year in China, most of which are less than 10 pm in diameter, causing serious damage to the land productivity of farmland and grassland in the source area.
Atmospheric pollution in the source and affected areas of dust storms, the increase of inhalable particulate matter (TSP) in the atmosphere, aggravated air pollution. From March to April 2000, Beijing area was affected by sandstorms, the air pollution index reached grade 4 or above for 10 days, at the same time, it affected many cities in eastern China, from March 24 to 30, the daily pollution index of 18 cities, including Nanjing and Hangzhou, exceeded grade 4.
(2) Sandstorms hazards
Sandstorms weather is a severe disastrous weather in Northwest China and Northern North China, which can cause houses collapse, traffic power supply blockage or interruption, fire, human and animal casualties, pollute the natural environment, destroy crop growth, and cause serious losses and great harm to national economic construction and people's lives and property safety. Sandstorm hazards are mainly in the following aspects:
①Production and life are affected.Dust storms carry a large amount of sand and dust to shade the sun. The cloudy weather reduces the solar radiation, several hours to more than a dozen hours of poor visibility can easily make people feel depressed and reduce the efficiency of work and learning.Light people can cause a large number of livestock to suffer from respiratory and gastrointestinal diseases. In severe cases, it will lead to the death of a large number of “Spring Lack” livestock, scraping away fertile soil, seeds and seedlings from farmland.Sandstorms can also aggravate the wind erosion and desertification of the surface soil, cover the leaves of plants with thick sand and dust, affect the normal photosynthesis, resulting in crop yield reduction.
②Causing loss of life and property, affecting traffic safety.Dust storms can kill people and animals, collapse buildings and reduce agricultural production. Affect traffic safety, cause the aircraft can not take off or land normally, make car and train car glass damage, stop operation or derailment.
③Harm human health. The health damage caused by sandstorms is multifaceted. Skin, eyes, nose and lungs are the first places to be exposed to sandstorms, and the most seriously damaged areas are the skin, eyes, nose and lungs. Damage to skin, eyes, nose, throat and other direct contact sites is mainly irritant symptoms and allergic reactions, while pulmonary manifestations are more serious and widespread.
④Causing the deterioration of the ecological environment. Sandstorm can aggravate land desertification, cause serious pollution to the atmospheric environment, cause tremendous damage to the ecological environment, and have an important impact on infrastructure such as transportation and power supply lines.
On May 5, 1993, a strong sandstorm in China caused a direct economic loss of 5.6 billion yuan.The total area affected by the sandstorm is about 1.1 million km, involving 72 County flags and 12 million people in 18 cities of 4 provinces (districts) in Northwest China.There were 85 deaths, 31 missing and 264 wounded, hundreds of thousands of livestock were killed and lost, hundreds of thousands of hectares of farmland, fruit forests and young forests were damaged, hundreds of plastic greenhouses were destroyed, and the infrastructure, power supply lines, roads and railways of grasslands, pastures and salt farms were seriously damaged.In addition, dust will pollute the atmosphere of the city and directly affect people's health, the indirect loss is incalculable.
Role of sandstorms in ecosystem
Although there are many hazards of sandstorms, the whole process of sandstorms is also an indispensable part of the natural ecosystem.For example, the large amount of iron carried by Australian red sandstorms has proven to be an important source of nutrients for plankton in the Antarctic Sea, and phytoplankton can consume large amounts of carbon dioxide to mitigate the harm of the greenhouse effect.Therefore,the impact levels of sandstorms are not all negative. On the other hand, dust storms may be a sign of the Earth's response to environmental changes, just as we cough when we catch a cold to remove waste from our airways.
In addition to the Hawaiian Islands, scientists have found that the Amazon Tropical Rainforest, the largest green lung on the planet, also benefits from dust storms, an important source of nutrients is dust in the air, because dust aerosols contain elements such as iron ions that help plants grow.
In addition, because dust storms are mostly born on dry and high saline-alkali soil, some of the soil grains carried by dust storms often contain alkaline substances, so they can often slow down the acid rain or soil acidification in the sedimentation area near the dust storms.
Prevention and control of sandstorms
(1) Warning signals of sandstorms
Warning signals of sandstorms are divided into three levels: yellow, orange and red, respectively. Shown in table 6-9.
(2) Preparing for sandstorms
① Close the doors and windows, seal the windows with adhesive tape, and seal the precision instruments.
②Prepare dust-proof and wind-proof articles such as masks and gauze towels.
③If it is a dangerous old house,which should be transferred to take refuge immediately.
④Kindergartens and schools should take temporary measures to suspend classes.
⑤Open-air collective activities or indoor large-scale gatherings should be stopped in time and evacuation work should be done well.
⑥Field work should be stopped in time and taken shelter in safe places.
(3) Essentials of dust storm avoidance
①Stay indoors, don't go out, especially those with poor resistance should stay indoors with closed doors and windows.
②If you are outdoors, stay away from trees, tall buildings and billboards and crouch on low walls that can shelter from wind and sand.
③In the field, you should lie on the leeward of a relatively high slope, or grasp solid objects, and never run around.
④Wear dustproof clothes, gloves, masks and glasses when you go out, and wash your face when you return to your room.
(4) Control and prevention measures of sandstorms
①Enhancing environmental protection and putting environmental protection to the height of legal system.
②Restoring vegetation and strengthening the biological protection system against sandstorms, protect and restore forest and grass vegetation according to law, prevent further expansion of land desertification and minimize dust sources.
③According to local conditions in different regions, disaster prevention, disaster resistance and relief plans are formulated, various disaster mitigation technologies are actively promoted, and a number of demonstration projects are constructed to gradually promote and further improve the regional comprehensive defense system.
④Strengthen the scientific propaganda on the relationship between the occurrence and harm of sandstorms and human activities, so that people realize that once the environment they live in is destroyed, it will be difficult to recover. It will not only aggravate natural disasters such as sandstorms, but also form a vicious circle. Therefore, people should consciously protect their living environment.
⑤Establishing accurate sand-dust storm forecast and doing disaster prevention work well in advance can reduce the loss to the minimum.
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