日本一级婬片A片AAA毛片价格,成人做爰A片C0m,日本在线免费观看,国产一区在线免费观看,一级a片在线观看

Feedback

Navigation:Home  ? News  ?  Company News

“Aerosol transmission of COVID19”? With gaseous VOC

  • Published: 2020-02-25 12:38:25
  • Hits: 1980

On February 8, 2020, the Shanghai Municipal Government held a press conference on epidemic prevention and control. At the press conference, health and epidemic prevention experts said that the transmission of pneumonia caused by the new coronavirus is mainly direct transmission, aerosol transmission and contact transmission. [1]

However, in the "Diagnosis and Treatment of COVID19 (Trial Fifth Edition)" announced by the National Health and Medical Commission, the transmission route of the virus is described as follows-"transmission routes such as aerosol and digestive tract are yet to be clarified" . [1]

And whether or not "aerosol" is also a transmission channel of "new coronary pneumonia". However, "aerosols" and "gaseous VOCs" are indeed the main causes of urban air pollution.

Aerosol refers to a gaseous dispersion system composed of solid or liquid particles suspended in a gaseous medium. The density of these solid or liquid particles can be slightly different from the density of the gas medium, or they can be very different; the size of the particles is generally between 0.001 and 1000 μm; the shape of the particles is diverse, and can be nearly spherical, such as liquid mist beads, It can also be flake, needle and other irregular shapes. From the perspective of fluid mechanics, aerosols are essentially multiphase fluids in which the gaseous phase is a continuous phase and the solid and liquid phases are dispersed phases. [2] Aerosol is a sol formed by solid or liquid as dispersant (also called dispersed phase) and gas as dispersion medium. It has colloidal properties, such as: scattering of light, electrophoresis, Brownian motion and other characteristics. The solid and liquid particles in the atmosphere undergo Brownian motion without sedimentation due to gravity, and can be suspended in the atmosphere for months and years. [3]

 VOC is an abbreviation of volatile organic compounds. VOC in the general sense refers to volatile organic compounds; but the definition in the sense of environmental protection refers to the active type of volatile organic compounds, that is, the types of volatile organic compounds that can cause harm. VOC is an abbreviation of volatile organic compounds. The main components of VOC are: hydrocarbons, halogenated hydrocarbons, oxygen hydrocarbons and nitrogen hydrocarbons, which include: benzene series, organic chlorides, Freon series, organic ketones, amines, alcohols, ethers, esters, acids and petroleum hydrocarbon compounds Wait.

The World Health Organization (WHO, 1989) defines total volatile organic compounds (TVOCs) as volatile organic compounds with a melting point below room temperature and a boiling point between 50 and 260 ° C.

The surface structure of aerosol particles is very complex and some are relatively smooth, but most of the particles have rough surfaces. Therefore, the surface of the particles can be used as a place where the particles react with the atmosphere or catalyze oxidation reactions. For example, sulfur dioxide can be catalytically oxidized on the surface of aerosol particles (the surface contains transition metals such as iron or manganese) to produce sulfates, or gas phase oxidation can occur to produce sulfate aerosols (particulates, secondary pollutants). The latter can be transported over long distances and reach the ground after settling (dry settlement) over hundreds of kilometers or being washed away by rain (wet settlement), thereby causing acidification of soil and water bodies and causing environmental and ecological harm. [3] Single

Aerosols and VOCs, one is aerosol particles, and the other is volatile organic compounds with a melting point below room temperature and a boiling point between 50 and 260 ° C. The combination of the two has become one of the main causes of urban air pollution. Taking the common urban aerosol as an example, the formation of particles can also be nucleated by VOC particles with low vapor pressure; it can also be the concentration, condensation and collision of low vapor pressure VOCs on existing particles.

Organic matter in aerosols, they generally account for 10% to 50% of the total mass of aerosols, and there are many types of them that have a great impact on human health and the atmospheric environment. [4] [5]

Tel:025-84414484 Fax:025-86647595 Address:Wenying Road No.3,Binjiang Development Zone Jiangning District,Nanjing City


      Copyright by Nanjing Carbon Recycle Biomass Energy Co.,Ltd.
好吊视频一区二区三区 | 欧美成人A片久久久电影 | 缅甸午夜性猛交XXXX | 99久久久无码国产精品免费四季 | 中文字幕AV在线中文字幕 | 日美韩蘑菇无码视频 | 国语对白做受 69 | 国产人妻人伦精品熟女A玄幻 | 亚洲婷婷一本高清 | 搡80老女人老太婆视频在线观看 | 国产成人a亚洲精品无码青草-百度 | 3D精品啪啪一区二区免费 | 91在线精品无码秘 竹菊 | 试看120秒一区二区三区 | 红桃视频在线视频一区 | 少妇精品无码一区二区三区大长颈 | 国产精品中文字幕在线观看 | 韩国无码A片1区2区 午夜精品视频在线观看 | 毛片无码高清蜜桃视频 | 波霸巨大乳一区二区三区 | 本日美女产国热妞久999 | 日韩女女同性AA女同 | AV鲁丝一区鲁丝二区鲁丝四区 | 熟女如虎的丰满熟妇啪啪 | 一级毛片免费看高清经典小说 | 国产一级a毛一级a在线观看 | 91一区二区三区在线观看 | 成人无码精品一区二区黑寡妇在线 | 色婷婷五月色综合AⅤ色欲 蜜臀av粉嫩av色欲av | 麻豆亚洲AV成人无码一区精品 | 多毛人妻日韩精品无码专区加勒比亚 | 国产精品99久久久久久久 | eeuss鲁片一区二区三区四川 | 9孩岁女精品A片BBB | 99精品在线免费视频 | www久久久久久久久久 | 星空传媒精品黄色视频 | 毛片无遮挡A片免费无码 | 国产91 丝袜在线播放九色 | 91又大又爽又黄无码A片 | 国产成年女一区二区三区 |