Does the fresh air system have an impact on dusty weather?

Sandstorm is a general term for sandstorm and sandstorm, which refers to the weather phenomenon that strong winds drag a large amount of dust on the ground into the air, making the air particularly turbid and the horizontal visibility lower than 1 km, in which sandstorm refers to a sand-laden storm formed by strong winds blowing a large amount of dust near the ground; Sandstorm is a storm formed by strong winds, which brings a lot of dust and other particles into the sky. Generally, wind speed and visibility are used to classify the intensity grade of sandstorm. At present, the intensity of sandstorm is divided into four levels: level 4 ≤ wind speed ≤ 6,500 m ≤ visibility ≤ 1000m, which is called weak sandstorm; Grade 6 ≤ wind speed ≤ 8,200 meters ≤ visibility ≤500 meters, which is called medium-intensity sandstorm; The wind speed is ≥9 and the visibility is ≤200 meters, which is called a strong sandstorm. When it reaches its maximum intensity (instantaneous maximum wind speed ≥ 25m/s, visibility ≤ 50m, or even reduced to 0m), it is called extremely strong sandstorm (or black storm, commonly known as "black wind"). The hazards of sandstorms can be roughly divided into four categories: sand burial, wind erosion, strong wind attack and air pollution. Due to the influence of sandstorm, the whole earth discharges 2~200 tons of dust into the air every square kilometer every year. It is observed that the dust in Central Asia can be transported to the Hawaiian Islands 10,000 kilometers away by the westerly airflow. These dusts contain many toxic minerals, which are harmful to human body, livestock, crops and trees, and can cause eye diseases and respiratory infections. 1On the afternoon of May 5, 993, a strong sandstorm occurred in northwest China. At first, a sandstorm wall appeared in the northwest of Jinchang. Ten minutes later, the city was dusty, dark and opaque. From time to time there was dull thunder, and a terrible scene appeared between heaven and earth. This state lasted for nearly three hours in Jinchang, and swept eastward to Wuwei, Baiyin, Alashan League, Inner Mongolia, and Yinchuan, Ningxia, wreaking havoc in Fiona Fang for 500 kilometers. It lasted for five hours, hundreds of people were killed, injured and missing, and the direct economic loss was 540 million yuan, which also caused many environmental problems. 1. Macro measures ① Carry out extensive and in-depth publicity and education on environmental awareness to improve the ideological level of the whole nation. Care and care for the environment, consciously participate in the transformation and construction of the environment, and form the fashion of the whole society. ② Improve laws and regulations, strengthen law enforcement supervision, protect the environment according to law, and promote desertification control. ③ Strictly implement the family planning policy, control the excessive population growth, and constantly improve the quality of the population. ④ Developing various scientific and educational undertakings in desertification areas. Cultivate grassroots scientific and technological forces, improve the rural scientific and technological market as soon as possible, do a good job in scientific and technological services, and improve the cultural and scientific quality of people in desertification areas. ⑤ Establish an effective investment mechanism and a management mechanism in line with the current national conditions. ⑥ Establish an advanced desertification dynamic monitoring and forecasting system, make good decisions, and do a good job in information management and service. ⑦ Carry out a lasting green revolution in desertification areas, accelerate the reversal of desertification process, and gradually improve the basic functions of agricultural ecosystems. (8) Strengthen international exchanges and cooperation in combating desertification and strive for funds and foreign aid. (9) Accelerate the adjustment of industrial structure, rationally allocate the proportion of agriculture, forestry and animal husbandry according to market requirements, actively develop aquaculture and processing industries, divert rural surplus labor force, and reduce the pressure of population on land. (10) Optimize the energy structure in agricultural and pastoral areas, and vigorously advocate and encourage people to use unconventional energy sources such as wind energy and light energy to reduce the damage to forests, grasslands and other resources. 2. Technical measures (1) Biological measures ① Seal sand to facilitate afforestation and grass planting, restore natural vegetation, take certain protective measures (set fences), establish necessary protection organizations (forest protection stations), prohibit human and animal damage, give plants time to thrive, and gradually restore natural vegetation. At the same time, the enclosure can be replanted and managed manually to accelerate the ecological reversal. (2) Aerial seeding for afforestation, planting grass and fixing sand has the characteristics of high speed, less labor, low cost and good effect, and is especially suitable for vegetation restoration in remote deserts and barren hills. The key technical problems to be solved in aerial seeding are: predicting climate, selecting site conditions, determining suitable sowing area, determining suitable sowing amount, seed treatment technology, preventing and controlling livestock and poultry diseases and insect pests, and enclosure protection. (3) Planting, cutting, seedling raising, planting grass, direct seeding, afforestation and sand fixation: Sow on grassland quicksand to ensure that seedlings reach a certain density (15-20 plants /m2), a certain height (15-20 cm) and a certain area (