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
46
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.
Air-conditioning may have ill effect on human body in all of the following ways EXCEPT that______.
选项
A、much exposure may make people feel annoyed
B、harmful chemicals in the ventilation system may cause cancers
C、much exposure to low temperature may cause immune diseases
D、people may suffer from headache in an air-conditioned office
答案
C
解析
细节题。第四段末句指出,越来越多的研究证明,过多地接触正离子(在有空调的房间中)会导致头疼、疲惫,并产生烦躁情绪,故[A]和[D]是空调系统的负面作用;第五段末句指出,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,故[B]也是危害之一;末段最后两句指出,在有空调的环境下工作或生活,人体免疫系统会变得脆弱,因而更容易患上如伤风、流感一类的疾病。这里是说免疫力低下会导致伤风、流感,并非免疫系统疾病,故[C]为答案。
转载请注明原文地址:https://kaotiyun.com/show/6x7O777K
0
专业英语八级
相关试题推荐
InAustralia,theMedicaresystemalsomeets______ofthebillforprivatehospitaltreatment,whilepatientspaytherest.
AndrewCarnegie,knownastheKingofSteel,builtthesteelindustryintheUnitedStates,and,intheprocess,becameoneof
Theerrorinthesentence"Ilostmyroad"isanexampleof______.
InwhichyeardidCanadabecomeacountry?
我不敢说生命是什么,我只能说生命像什么。生命像向东流的一江春水,他从最高处发源,冰雪是他的前身。他聚集起许多细流,合成一股有力的洪涛,向下奔注,他曲折的穿过了悬崖峭壁,冲倒了层沙积土,挟卷着滚滚的沙石,快乐勇敢地流走,一路上他享受着他所遭遇的一切
我先是被鸟的鸣声吵醒的。是个夏日的清晨,大概有几十只小鸟在我窗外的槭树上集合了,除了麻雀的吱喳声之外,还有那种小绿鸟的嘤嘤声。我认得那种声音,年年都会有一两对小绿鸟来我的树上筑巢,在那一段时间里,我每天都能听到它们那种特别细又特别娇的鸣声.听了就
破碎的事物就这样印满了重重叠叠的生命的影迹,那么沉厚,那么绰约,却那么美丽。同样,很残忍的,我相信破碎的灵魂才最美丽。我喜欢看人痛哭失声,喜欢听人狂声怒吼,喜欢人酒后失态吐出一些埋在心底发酵的,住事。我喜欢素日沉静安然的人喋喋不休地诉说苦难,一向
七十五岁时重返文坛,丁玲没有时间为自己的遭遇呻吟叹息。她就像年轻人一样急切地捧出了一枝报春的红杏——《杜晚香》,忘情地投入新的生活和创作。她奔波于大江南北,游历于欧、美、澳大陆,会见各种人,发表演说,奋笔疾书,写散文,写评论,每年都有十多万字的新作,每年都
如果回归自然,各有不同的方式,后人总是尊重前辈的人生最后一次选择。一位朋友偶然讲起一件事,犹如一篇小小说,听者动容。在新开发的从林里,一条蜿蜒的小径上,一个衣着素色的女子踽踽独行,径直走向林子里的一棵树。这里许多树大小参差不一,不过都长得很快,新生的树叶
我常见许多年青的朋友,聪明用功,成绩优异,而语文程度不足以达意,甚至写一封信亦难得通顺,问其故则曰其兴趣不在语文方面。又有一些位,执笔为文,斐然可诵,而视数理科目如仇讐,勉强才能及格,问其故则亦曰其兴趣不在数理方面。如果他们觉得某些科目没有趣味,便撇在一旁
随机试题
在教学目标制定时要强调用精确、具体、可操作的形式来表达教学目标,以及反映教学活动实施的预期结果和学生身心方面的行为变化。这属于()
冷热流体在换热时,并流时的传热温度差要比逆流时的传热温度差大。 ()
根据下列案情材料,按照《法律文书写作》教材I中的要求,拟写第一审刑事判决书。2001年×月×日,××市中级人民法院由审判长李×生、审判员刘×文、张×江依法组成合议庭,由孙×河担任书记员,公开开庭审理了王×东杀人一案。×市人民检察院检察员洪×仁出庭
LD同工酶结果在急性心肌梗死时最典型的改变是
运用比较法估价,选择可比实例应符合的基本要求包括()等。
( )比较适用于工作范围很难确定、专业施工技术要求高且急于开工的工程。
固定资产贷款的借款申请人须提交的材料文件包括()。
资料同上。下列有关乙公司非货币性资产交换的会计处理,不正确的是()。
右图反映单位体积空气所能容纳的最大水汽量与气温的关系。完成下列问题。通过上述实验可以推知,相对湿度的变化主要取决于气温,其一般规律是()。①气温高,相对湿度小②气温低,相对湿度小③清晨相对湿度最大④午后相对湿度最大
(2007下监理)在面向对象方法中,对象可看成是属性(数据)以及这些属性上的专用操作的封装体。封装是一种_____(1)技术,封装的目的是使对象的_____(2)分离。(2)
最新回复
(
0
)