首页
登录
职称英语
About two-thirds of the world’s population is expected to live in cities by the
About two-thirds of the world’s population is expected to live in cities by the
游客
2025-01-28
20
管理
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 10 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 publicized dangers is that of Legionnaire’s disease, which first recognized 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 smoke 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° C, our normal temperature. This leads to a weakened immune system and thus greater susceptibility to diseases such as colds and flu. [br] The word "adversely" underlined in Paragraph 6 means ______.
选项
A、contradictorily
B、negatively
C、eventually
D、audaciously
答案
B
解析
adversely意为“不利地,有害地”。本段的末句指出空调会弱化人的免疫系统.使人易生病,故可看出是负面、消极的影响,故选B“消极地,负面地”。同时排除A“矛盾地”、C“最终地”和D“大胆地”。
转载请注明原文地址:https://tihaiku.com/zcyy/3933074.html
相关试题推荐
Peopleofallcountriesareexpectedto______theprinciplesoftheUnitedNation
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
Untilrecently,mostpopulationgrowthhasoccurredinrelativelydenseurba
随机试题
Itwas3:45inthemorningwhenthevotewasfinallytaken.Aftersixmonths
Itcanbeinferredthatthedeafboy’slifeintheorphanagewas[br]Itcanbe
关于集气管,下列说法不正确的是()。A.集气管是汇集从各炭化室导出的粗煤气
关于饮片的供应,下列说法不正确的是A.保管 B.消毒 C.查斗 D.调剂
沟通、领导和磋商是属于()的技能。A.项目管理 B.一般管理 C
A.嵌顿性疝 B.难复性疝 C.绞窄性疝 D.可复性疝 E.滑动性疝疝块
根据《金融机构反洗钱规定》,国务院反洗钱行政主管部门是()。A.商务部 B.
项目法人应自工程开工之日起()个工作日内,制定法人验收工作计划,报法人验收监督管
我国证券公司的设立采取()。A:报备制B:审批制C:备案制D:注册制
下列关于重整计划草案的表决分组,表述错误的有()。A.拖欠的划入社会统筹账
最新回复
(
0
)