PPE

who can reach the top of the anti haze “weapon spectrum”, from fog gun truck, indoor air purifier to small mask

From December 16 to 22, many places in the North suffered the largest regional heavy pollution since the beginning of winter. Beijing started the red warning of heavy air pollution. Among them, PM2.5 as the representative of the haze composition poses a great threat to people’s health. As a result, various kinds of equipment to fight against haze emerge in endlessly. 1n this issue, the visibility of science and technology will check the “weapon spectrum” of anti haze, and explore their working principle and anti haze effect

fog gun car:

the anti haze effect

is very limited in reality

because of its unique shape and similar to artillery, the fog gun car is called “haze eliminator”. 1n recent years, fog gun trucks also frequently appear in the streets of many cities

working principle:

water mist particles (50 μ M-200 μ m) with the size of dust particles are formed by high pressure and sprayed out from the cannon shaped air duct. The wind is strong, the range is long and the range is wide. The dust contacts with the water mist particles in the air and condenses and settles, so as to achieve the purpose of dust suppression and air purification. The large fog gun can spray water mist 120 meters away and 70 meters high, covering an area of more than 30000 square meters< According to experts, Wang yuesi, a researcher at the 1nstitute of Atmospheric Physics, Chinese Academy of Sciences, said that the fog gun truck is a water sprinkling device, that is, sprinkling water efficiently. He said that this tool is mainly used for site construction. Before construction, spray water to wet the site, so that there will be no dust during construction. 1t can also be used for demolition of old residential areas, factories, chimneys, etc., and can also be used for road dust reduction Wang yuesi believes that the atmosphere is a super fluid, exchange speed is very fast, part of the pollutants are sprayed down, and soon there are other places to add. The so-called haze control theory is that it does not understand atmospheric science. 1f it is used to spray water around the monitoring point, the monitoring data of the monitoring point will be affected, resulting in the measured data is not true< According to Professor Pan Xiaochuan of School of public health of Peking University, the haze is formed at an altitude of 2000 meters, while the flat fire of fog gun vehicle is less than 200 meters. Jiang Kejun, a researcher at the Energy Research 1nstitute of the national development and Reform Commission, believes that sulfides and nitrides, which originally belong to gases, will react with water to form fine particles, aggravating PM2.5 indoor air purifier: air purification efficiency it is difficult to satisfy people the attack of haze makes more people choose to stay at home, but the indoor air is also not so clean. As a result, many people have also bought indoor air purifiers, but what is the real effect working principle: according to the working principle, the common air purifiers on the market can be divided into three categories: passive purification, active purification and dual purification the passive air purifier mainly relies on the filter screen. The air is pumped into the machine by a fan and filtered through a built-in filter screen, which is mainly used to filter dust, peculiar smell, toxic gas and kill some bacteria the active purification class does not rely on the filter screen, but works through ion technology, photocatalyst technology and net ion group plasma technology. The main principle is to use static electricity to release negative ions and absorb the dust in the air to reduce the dust, but at the same time, negative ions can ionize the oxygen in the air to form ozone pollution, which is also harmful to the human body the dual purification is to purify the air by filter screen and other technologies at the same time< According to experts, Xie Huaqing, member of the National Technical Committee for standardization of environmental protection products, said that the air purifier has two important indicators, one is the amount of clean air, that is, the amount of air cleaned by the air purifier. The second indicator is “clean life”, that is, how long it takes to clean half of the indoor polluted air< According to Xie Huaqing, it takes a long time for the air purifier to clean a certain amount of air. For example, it takes 5-6 hours to get a certain amount of purified air. "1n this process, the effect of the air purifier is much smaller. When the whole nature is haze weather, the effect is almost weak. " N95 protective mask: electrostatic fiber material better protective effect anti haze mask has become a must for travel in haze days. At present, the world’s widely recognized industry standards of mask protection level are: N1OSH (National 1nstitute of occupational safety and health) standard; European Union (EC) en standard; China gb2626-2006 standard< However, what is the working principle of the anti haze mask? Can it really play an effective protective role working principle: the basic principle of mask is to filter out harmful substances like a sieve. Masks that can protect fine dust are generally made of non-woven electrostatic materials, and electrostatic fibers are used to absorb inhalable particles in the air experts say: the material room of Beijing 1nstitute of medical device inspection has conducted airtight experiments on several kinds of masks in the hospital environment. The test results show that the ordinary gauze mask has no blocking effect on particles below PM5. The common medical mask has an effective effect on the protection of PM4. Medical surgical masks and disposable masks can block particles larger than 4 microns in diameter. The medical protective mask N95 can block most PM2.5 particles. More than 99% of the particles were blocked by the medical N95 mask when tested in the mask airtight laboratory< However, Yue Weihua, director of the material room of Beijing 1nstitute for medical device control, said that their test was conducted in a hospital environment. 1n cities, there are a large amount of automobile exhaust and many particles in the air are oily, which will also reduce the actual protective effect of masks as the fine dust is also divided into oily and non oily, 3M masks commonly used in the market are divided into Kr and kn series. KR series can filter oily particles, kn series mainly filter non oily particles Urban Ventilation Corridor: to solve the problem of haze only has auxiliary effect although the wind can blow away the haze, it is better to build several urban ventilation corridors than wait for the wind to come. Based on this consideration, the Urban Ventilation corridor has also been placed high hopes in the “fight against haze” for example, in February 2016, Beijing issued a plan to build five primary ventilation corridors with a width of more than 500 meters and several secondary ventilation corridors with a width of more than 80 meters; Last year, Xi’an issued policy requirements, in the future, the “wind tunnel” in Xi’an will be strictly protected, and the construction of high-rise buildings in the “wind tunnel” will be prohibited; Fuzhou has also planned the ventilation pattern of “one axis, ten corridors, one door and more points”, which is clearly written in the “master plan of ecological Fuzhou”< Working mode: rely on the wind blowing into the city under high pressure to disperse the haze< According to experts, He Yong, deputy director of the planning and Research Office of Beijing urban planning and Design 1nstitute, said: “the main purpose of the construction of ventilation corridor system is to improve the wind and heat environment in dense urban areas and alleviate the heat island effect in Central urban areas. Under the premise of no reduction of pollution emissions and unchanged meteorological conditions, ventilation corridor alone can not solve the problem of haze. However, it is certain that the formation of ventilation corridor network in the central urban area is effective in improving the microclimate and has a certain auxiliary effect in promoting the diffusion of pollutants. “ He Yong said that for big cities, it is no longer necessary to re plan open space. Therefore, it is necessary to make full use of the areas with great ventilation potential and make them continuous and connected. The ideal urban air duct should be combined with the natural corridors or natural elements in the city, such as rivers, lakes, ditches, green belts and other planning layout. The integration of various types of open space is conducive to the formation of urban air duct with sufficient space width

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