首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
About two-thirds of the world’s population is expected to live in cities by the year 2020 and, according to the United Nations,
About two-thirds of the world’s population is expected to live in cities by the year 2020 and, according to the United Nations,
admin
2016-08-19
77
问题
About two-thirds of the world’s population is expected to live in cities by the year 2020 and, according to the United Nations, approximately 3. 7 billion people will inhabit urban areas some ten years later. As cities grow, so do the number of buildings that characterize them: office towers, factories, shopping malls and high-rise apartment buildings. These structures depend on artificial ventilation systems to keep clean and cool air flowing to the people inside. We know these systems by the term" air-conditioning".
Although many of us may feel air-conditioners bring relief from hot, humid or polluted outside air, they pose many potential health hazards. Much research has looked at how the circulation of air inside a closed environment— such as an office building—can spread disease or expose occupants to harmful chemicals.
One of the more widely publicised dangers is that of Legionnaire’s disease, which was first recognised in the 1970s. This was found to have affected people in buildings with air-conditioning systems in which warm air pumped out of the system’s cooling towers was somehow sucked back into the air intake, in most cases due to poor design. This warm air was, needless to say, the perfect environment for the rapid growth of disease-carrying bacteria originating from outside the building, where it existed in harmless quantities. The warm, bacteria-laden air was combined with cooled, conditioned air and was then circulated around various parts of the building. Studies showed that even people outside such buildings were at risk if they walked past air exhaust ducts. Cases of Legionnaire’s disease are becoming fewer with newer system designs and modifications to older systems, but many older buildings, particularly in developing countries, require constant monitoring.
The ways in which air-conditioners work to"clean"the air can inadvertently cause health problems, too. One such way is with the use of an electrostatic precipitator, which removes dust and smote particles from the air. What precipitators also do, however, is to emit large quantities of positive air ions into the ventilation system. A growing number of studies show that overexposure to positive air ions can result in headaches, fatigue and feelings of irritation.
Large air-conditioning systems add water to the air they circulate by means of humidifiers. In older systems, the water used for this process is kept in special reservoirs, the bottoms of which provide breeding grounds for bacteria and fungi which can find their way into the ventilation system. The risk to human health from this situation has been highlighted by the fact that the immune systems of approximately half of workers in air-conditioned office buildings have developed antibodies to fight off the organisms found at the bottom of system reservoirs. Chemical disinfectants, called"biocides",that are added to reservoirs to make them germ-free, are dangerous in their own right in sufficient quantities, as they often contain compounds such as pentachlorophenol, which is strongly linked to abdominal cancers.
Finally, it should be pointed out that the artificial climatic environment created by air-conditioners can also adversely affect us. In a natural environment, whether indoor or outdoor, there are small variations in temperature and humidity. Indeed, the human body has long been accustomed to these normal changes. In an air-conditioned living or work environment, however, body temperatures remain well under 37℃, our normal temperature. This leads to a weakened immune system and thus greater susceptibility to diseases such as colds and flu.
Which of the following substance can NOT be found directly from an old ventilation system?
选项
A、Chemical disinfectants.
B、Bacteria.
C、Fungi.
D、Pentachlorophenol.
答案
D
解析
细节题。倒数第二段第二句指出,在旧式空调系统中,用于循环的水储存在特制的贮液器中,而贮液器的底部就是进入通风系统中的细菌和真菌的滋生地。第四句指出,为了达到无菌的目的要在贮液器中加入化学消毒剂,又称“杀菌剂”,当其剂量到达一定程度时也会变得危险,这是因为这类杀菌剂中往往含有五氯苯酚一类的化合物,后者与腹部癌症的发作有着极其密切的关系。因此细菌、真菌和化学消毒剂都是可直接找到的物质,故排除[A]、[B]和[C];“pentachlorophenol”只是消毒剂成分中的一种物质,不是直接存在于空调系统中的,故答案为[D]。
转载请注明原文地址:https://kaotiyun.com/show/nx7O777K
0
专业英语八级
相关试题推荐
WhichofthefollowingisNOTafricativeinEnglish?
OnepeculiarfeatureofthefeudalsystemofEnglandwasthatalllandownerstooktheoathofallegianceto______.
First,whilelanguageprovidesameansofsayinganddoingthings,teachingisgenerallybeingdivorcedfromtheusewemakeof
Kissingissocommonthoughwerarelyaskwhyhumanstouch【M1】______theirlipstogethertoshowaffection.Oneobviousanswer
Oneofthemanyquestionsbroughtupisinregardswithwhetherornotcloningshouldbeanoptionfor【M1】______parentsthata
Fromaveryearlyage,perhapstheageoffiveorsix,IknewthatwhenIgrewIshouldbeawriter.Betweentheages【M1】______
我在山坡的小屋里,悄悄掀起窗帘,窥见园中大干世界,一片喧闹。(2003年真题)
要一个人独自进食,即使不算重罚,在中国文化中通常也被视为不幸,一种不无悲凉的境地。汉语对吃独食的描述,大都乏善可陈,一句“胡乱吃了些”搪塞过去。中国人的社会中,人必须借饮食与他人沟通,与社会上的人形成生命共同体之感受。如今,大家庭在解体,晚婚、单
我跟所有其余的人一样,生活在这世界上,是为着来征服生活。我也曾参加在这个“搏斗”里面。我有我的爱,有我的恨,有我的欢乐,也有我的痛苦。但是我并没有失去我的信仰:对于生活的信仰。我的生活还不会结束,我也不知道在前面还有什么东西等着我。然而我对于将来却也有一点
人生有三重境界,这三重境界可以用一段充满禅机的语言来说明,这段语言便是:看山是山,看水是水;看山不是山,看水不是水;看山还是山,看水还是水。这就是说一个人的人生之初纯洁无瑕,初识世界,一切都是新鲜的,眼睛看见什么就是什么,人家告诉他这是山,他就认
随机试题
生产现场起重、高空作业常用的辅助用具棕绳是由()编制而成的。
对那些对本企业有疑问的消费者,最好采用()
以下属于资产负债表项目的有()。
(2017年)下列各项中,可以作为企业产品定价目标的有()。
根据《银行账户管理办法》的规定,企业对更新改造的资金可以申请开立的银行账户是( )。
某股份有限公司董事会召开会议,该次会议召开的情况以及讨论的有关问题如下:(1)股份公司董事会由7名董事组成,出席该次会议的董事有董事A、董事B、董事C、董事D,董事E因出国考察不能出席会议;董事F因参加人民代表大会不能出席会议,通过电话委托董事A
敦煌石窟中有一幅画,画中,佛在打坐,群魔正在打扰他,这些群魔有的嘴里在向佛喷火,于是李约瑟立刻得出结论,这是中国最早的火焰发射器,或者是喷火枪的图片,证据确凿。然后更进一步得出结论,中国喷火枪的使用晚于投射炸药包的火炮,早于火箭。就凭一幅宗教神话壁画,李约
(江苏2010A—27)2010年2月15日后第80天的日期是()。
A.SellB.poorestC.shunD.perhapsPhrases:A.donot【T13】______itandcallithardnamesB.Itlooks【T14】______whenyouare
A、Doherhomework.B、Cleanthebackyard.C、Washclothes.D、Enjoythebeautifulday.C本题属于第二个说话者中间带but的转折题。But后面是答案。本题But后面的话是:有许
最新回复
(
0
)