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Drawing: Cai Huawei
"9-11 floor high-rise building is dust and floor, dirty air to this height will pause, where the highest density of pollutants ......" This is about building layers of dust and say widespread, causing some concern. Young ash layer exist? Particulate matter in the air in the highly contaminated areas gathered 9-11 layer formed it? People's Daily "confirmation" column reporter interview survey found that the so-called "Young ash layer 9-11 floor is" unscientific statement.
One question: 9-11 most polluted?
[Respond] PM10, PM2.5 concentration less each floor
In a real estate sales unit Yinchuan City neighborhood of Forest Park, salesman Liu Lijuan said, "Young ash layer is a layer of 9-11," saying she heard, but also customer advice when asked to buy a house, but feeling no impact on sales .
In Chengdu, Sichuan outside the ring a new disc, Yang Xiaogang with the whole family to pick room, when asked would not vote 9-11, he flatly refused:. "It is said that the layers are not selected Young ash layer, most polluted. "
Guangzhou Han with real estate experts said,http://www.from-zao.com/cgi-bin/tkbbs1/tkbbs1.pl?page_num=1%3Cbr+/tkbbs1.pl?page_num=1, "the building is Jan 9-11 ash layer," this argument, originated in 2003, an article entitled "Confessions of sales lady the truth," the network Wen,http://www.ez-netlife.com/bbs01/patio.cgi, this web text with "Secret,woolrich outlet," the voice said: "Do not think that a good level of 9-11 floor,moncler femme, the floor is just dust and floor, dirty air to this height will stop." text of the opinion has not been scientifically proven, but this view spread, people of true and false Mo identified.
Sichuan Environmental Monitoring total Zhanfuzhanzhang Robinson told reporters that the so-called dust and mainly particulate matter, depending on the particle size, divided into three types: one is the particle size ≤100 microns; one is PM10, particle size ≤10 microns; one is PM2.5, particle size ≤2.5 microns. These three sources of particulate matter in the environment, pollution and there is a time and a high degree of composing are not the same.
Ningxia Environmental Monitoring Center Zhanfuzhanzhang Chen Gong introduction, the formation mechanism of PM2.5 is dust, sulfur dioxide, nitrogen oxides, water vapor and other substances encountered in the air, forming acidic condensation nuclei. From the meteorological point of view and condensation nuclei formation mechanism, the so-called Young ash layer 9-11 layer does not exist.
Associate Dean of Environmental Science and Engineering, Tianjin University Professor Ma Degang he said that in the field of environmental science, and there is no layer of dust and say, 9-11 layer can not generally think worst contaminated buildings. "Air movement is in three-dimensional space, not only vertical movement, but also horizontal movement to high-rise buildings, for example, does not consider the impact of wind conditions, the yin and yang surface due to convection solar radiation is different, it is difficult to floor to Distribution distinguish pollutants. "
Guangzhou Environmental Monitoring Station staff said, including PM2.5 dust concentrations, including building height and has nothing to do with the "micro-climate" Area of building-related. "From the ground a few meters to tens of meters, near the ground and particulate matter air quality is relatively stable distribution, PM2.5 concentration difference is not large .9-11 Young ash layer is a layer has no scientific basis."
Second question: whether the dust distribution law?
[Responded] by geography,canada goose femme, weather,http://www.jinwantang.com/bbs/thread-3672982-1-1.html, and greater impact on the industrial structure; large particles of dust concentration slightly lower floors
Chen Gong believes that the distribution of dust in the case of urban pollutants and emission sources, weather conditions, surface roughness, surface construction layout of a relationship, "the dust around the construction site, the top and sides of the road, the distribution of a large surface area exposed."
Yinchuan City Environmental Monitoring Station Master Zhang Xinrong believe, dust and urban residence status also elevated source, amount and distribution of low loader source related. Large industrial enterprises, such as thermoelectric belong elevated source, elevated source emission radiation radius of altitude, wind direction, building density, are the determining factor.
Made Gang said: "suspended in the atmosphere of the solid particles or liquid droplets substances (including PM10 and PM2.5) aerosol collectively, it is the primary pollutant causing haze." Aerosol concentration by geography, meteorology and geography Industrial Structure greater impact. Aerosol distribution with relevant sources, such as industrial emissions through the chimney to the high altitude, could seriously pollute some level; ground dust sedimentation obviously, may experience significant underlying. In addition a pollutant is also easy to generate secondary pollutants.
As for the distribution of large particles of dust, Chen Gong believes that the deposition surface down to human activities and particulates reason gravity and other factors, resulting in the lowest layers of air of buildings most "dirty." According to the vertical distribution of particulate matter tested in 1992 did, large dust particles distributed closer to the ground, the more up distribution less. "It was to do the following tests is 100 microns of dust particles, the larger dust particles. Were done by 2 layers, 4 layers, 8 layers,http://www.nch.com.au, 10 layers these four points,http://www.mama0471.com/home.php?mod=space&uid=356965, the results show that the larger dust particles,air max 90, the greater the weight produce deposition phenomenon is more evident, as the height increases the concentration of dust particles getting lower and lower. "
Three questions: PM2.5 how widely distributed?
[Respond] uniformly distributed in the atmospheric mixing layer, different cities mixing layer height
Recent frequent fog and haze, so that people are particularly concerned about PM2.5. In the end the distribution of PM2.5 in the air which range?
For PM2.5 borders,http://www.postyourflasher.com, Chen Gong represents, PM2.5 and other particulate matter mainly in the atmospheric mixing layer. According to reports, mainly the surface mixed layer is heated after sunrise, hot air rises, cold air fall, convection gradually strengthen, resulting in various properties of near-uniform mixing. "Contaminants in the mixed layer, convective mixing effect because it is easy to make a uniform distribution of air pollutants within the mixing layer. Therefore, mixing layer height is an important indicator of air pollution forecast,http://www.lionbrand.com/cgi-bin/faq-search.cgi, the mixing layer height is higher, pollutants diluted larger space, conducive to the spread of pollutants, pollutant concentration smaller; conversely,moncler soldes, the lower the mixing layer height, the greater the concentration of pollutants, to a large extent of the contamination. "
"PM2.5 is evenly distributed in a specific area. PM2.5 concentration in the Beijing area is higher than under normal circumstances Yinchuan, because not one level of pollutant emissions from two places." Chen Gong added.
Robinson reminded that when inversion effect produced (inversion: at a certain height with increasing height increasingly high temperatures), pollutants are transported and easy to spread, causing particulate matter within a height range of a relatively high concentration . But the height of the inversion layer is constantly changing with the atmospheric conditions,http://www.postyourshavedpussy.com, PM2.5 and other particulate matter also will be distributed diffusion, temperature inversion may be close to the top of the ground, it could reach more than 1000 meters, but within the scope of their hierarchy, PM2.5 the concentration will not have a big difference.
Guangzhou Environmental Monitoring Station staff said, according to the laser radar stations in different regions of the monitoring results under different weather conditions of vertical space, PM2.5 distribution within 300 m vertical range is uniform. Now real estate is generally about 100 meters, so there will not be much difference PM2.5 concentration of each floor.
(Original title: "Young ash layer 9-11 layer is" not based on (confirmation · explore the truth behind the noise)) |
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發表於 2015-11-3 18:25:00
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