人体会向外界释放细菌-凯发k8官网

人体会向外界释放细菌
文章来源:未知 文章作者:enread 发布时间:2012-03-29 05:21 字体: [ ] 
(单词翻译:双击或拖选)

a person's 1 presence in a room can add 37 million bacteria to the air every hour -- material largely left behind by previous occupants and stirred up from the floor -- according to new research by yale university engineers. "we live in this microbial soup, and a big ingredient is our own microorganisms," said jordan peccia, associate professor of environmental engineering at yale and the principal 2 of a study recently published online in the journal indoor air. "mostly people are re-suspending what's been deposited before. the floor dust turns out to be the major source of the bacteria that we breathe."

many previous studies have surveyed the variety of germs(细菌) present in everyday spaces. but this is the first study that quantifies how much a 3 human presence affects the level of indoor biological 4(气溶胶) .

peccia and his research team measured and 5 biological particles in a single, ground-floor university classroom over a period of eight days -- four days when the room was periodically occupied, and four days when the room was continuously vacant(空的) . at all times the windows and doors were kept closed. the hvac system was operated at normal levels. researchers sorted the particles by size.

overall, they found that "human occupancy was associated with substantially increased airborne concentrations" of bacteria and 6 of various sizes. occupancy resulted in especially large 7 for larger-sized fungal particles and medium-sized 8 particles. the size of bacteria- and fungi-bearing particles is important, because size affects the degree to which they are likely to be filtered from the air or linger(徘徊,消磨) and recirculate, the researchers note.

"size is the master variable," peccia said.

researchers found that about 18 percent of all bacterial 9 in the room -- including both fresh and 10 deposited bacteria -- came from humans, as opposed to plants and other sources. of the 15 most abundant varieties of bacteria identified in the room studied, four are directly associated with humans, including the most abundant, propionibacterineae, common on human skin.

peccia said carpeted rooms appear to retain especially high amounts of microorganisms, but 11 that this does not necessarily mean rugs and carpets should be removed. extremely few of the microorganisms commonly found indoors -- less than 0.1 percent -- are infectious, he said.

still, understanding the content and 12 of indoor biological aerosols is helpful for devising new ways of improving air quality when necessary, he said.

"all those infectious diseases we get, we get indoors," he said, adding that americans spend more than 90 percent of their time inside.

the researchers have begun a series of similar studies outside the united states.

the paper's lead author is j. qian of yale. other contributors are d. hospodsky and n. yamamoto, both of yale, and w.w. nazaroff of the university of california-berkeley.

the research was supported by the alfred p. sloan foundation.



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1 rc1xe     
adj.纯粹的;仅仅,只不过
参考例句:
  • that is a mere repetition of what you said before.那不过是重复了你以前讲的话。
  • it's a mere waste of time waiting any longer.再等下去纯粹是浪费时间。
2 zrqzo     
n.研究者,调查者,审查者
参考例句:
  • he was a special investigator for the fbi.他是联邦调查局的特别调查员。
  • the investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。
3 q0cxl     
adj.孤寂的,单独的;唯一的
参考例句:
  • a lone sea gull flew across the sky.一只孤独的海鸥在空中飞过。
  • she could see a lone figure on the deserted beach.她在空旷的海滩上能看到一个孤独的身影。
4 a9c7ea700e36caa4c48a8c693762372f     
n.气溶胶( aerosol的名词复数 );喷雾剂;(气体中的)浮粒;喷雾器
参考例句:
  • aerosols are present throughout the atmosphere. 气溶胶存在于整个大气层。 来自辞典例句
  • deodorants are available as aerosols or roll-ons. 除臭剂有喷雾装或滚抹装。 来自辞典例句
5 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
参考例句:
  • the doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • the young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
6 6hrx6     
n.真菌,霉菌
参考例句:
  • students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
  • the lawn was covered with fungi.草地上到处都是蘑菇。
7 jhxzrc     
n.穗( spike的名词复数 );跑鞋;(防滑)鞋钉;尖状物v.加烈酒于( spike的第三人称单数 );偷偷地给某人的饮料加入(更多)酒精( 或药物);把尖状物钉入;打乱某人的计划
参考例句:
  • a row of iron spikes on a wall 墙头的一排尖铁
  • there is a row of spikes on top of the prison wall to prevent the prisoners escaping. 监狱墙头装有一排尖钉,以防犯人逃跑。 来自《简明英汉词典》
8 dy5z8q     
a.细菌的
参考例句:
  • bacterial reproduction is accelerated in weightless space. 在失重的空间,细菌繁殖加快了。
  • brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。
9 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
10 bkzzzc     
adv.以前,先前(地)
参考例句:
  • the bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
11 5n4zxc     
adj.著名的,知名的
参考例句:
  • the local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • jim is noted for arriving late for work.吉姆上班迟到出了名。
12 nuszqq     
n.力学,动力学,动力,原动力;动态
参考例句:
  • in order to succeed,you must master complicated knowledge of dynamics.要取得胜利,你必须掌握很复杂的动力学知识。
  • dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。
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