首页
登录
职称英语
A useful definition of an air pollutant is a compound added directly or indi
A useful definition of an air pollutant is a compound added directly or indi
游客
2023-08-21
42
管理
问题
A useful definition of an air pollutant is a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled—a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.
Many of the more important air pollutants, such as sulfur oxides(硫化物), carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, natures output of these compounds dwarfs that resulting from human activities. However, human production usually occurs in a localized area, such as a city.
In this localized region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effect appears will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0. 08 parts per million(ppm), which is about 400 times its natural level. Carbon monoxide, however, has natural level of 0. 1 ppm and is not usually a pollutant until its level reaches about 15 ppm. [br] Which of the following statements is the fact about human generated air pollution in localized regions?
选项
A、It can be dwarfed by natures output of pollutants in the localized region.
B、It can overwhelm the natural system that removes pollutants.
C、It will damage areas outside of the localized regions.
D、With naturally occurring pollutants it will react harmfully.
答案
B
解析
由题干关键词in localized regions定位至第三段第一句可知,在局部地区,人类活动产生的污染物随时可能超出自然界净化系统的承载能力。因此B)“它能超出自然界净化系统的承受能力”正确。
转载请注明原文地址:https://www.tihaiku.com/zcyy/2943385.html
相关试题推荐
Ausefuldefinitionofanairpollutantisacompoundaddeddirectlyorindi
Ausefuldefinitionofanairpollutantisacompoundaddeddirectlyorindi
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Althoughrecentyearshaveseensubstantialreductionsinnoxiouspollutants
Ausefuldefinitionofanairpollutantisacompoundaddeddirectlyorindi
随机试题
(中南大学2007年试题)Thenormalhumandailycycleofactivityisofsome7~8hours’
【B1】[br]【B5】A、ofB、toC、withD、aboutB固定搭配题。solutiontosth.为固定搭配,意为“解决某事的方法”。
Thelocaltheaterhasitsspecialwaysofdrawingcrowds.UnliketheBroadwa
健康正常人的CD4/CD8T细胞的比值A.≥1.0 B.0.5~1.0 C.
提高职业道德修养的方法有()。A.认真学习职业道德理论 B.虚心接受职业道德
内科讨论的"痞满"出现在何部位A.胸部 B.腹部 C.少腹部 D.胃脘部
从公元前6世纪到公元1000年,我国在世界重大科技成就中所占的比例约达50%—7
某简支梁桥,计算跨径为20m,采用C30混凝土。该桥由5根主梁和5根横隔梁组成,
物业资产运营商模式的成功推广,必须满足约束条件有()。A:物业本身应当具有较高的
进口药品自首次获准进口之日起5年内,应报告该药品发生的A.新的不良反应 B.严
最新回复
(
0
)