昏黄雾霾笼罩着城市。北京PM2.5浓度测值今天非常高，很多地区超过700微克/立方米。而且这种严重污染的空气质量状况在未来三天难以好转。

Dim fog haze hangs over the city.Beijing PM2.5 concentrations measured value today is very high,Many areas more than 700 micrograms per cubic meter.And the serious pollution of air quality situation in the next three days is reduced.

　　在雾霾中，人们最想弄清楚的是：空气中那些看不见、摸不着的颗粒物究竟有多大危害，如何影响着自己的健康，如何避免这种危害？

In the fog in the haze,People want to make it clear that the:Those who can't see in the air/Touched particles exactly how much harm,How to affect their health,How to avoid this kind of harm?

　　这些问题并非没有答案，但追着答案再深一些，就会发现，现有的答案不够确切透彻。

These problems are not no answer,But after the answer to some deep,You will find,The existing the answer is not enough precise thoroughly.

　　北京大学医学部公共卫生学院教授潘小川研究PM2.5多年。去年12月，由他执笔的一份报告指出，如果2012年北京、上海、广州、西安四城市空气质量相对于2010年没有改善，因PM2.5污染造成的“超额死亡”人数将达8572人，由其带来的经济损失将达68亿元人民币。

Beijing medical university professor with the school of public health PanXiaoChuan research PM2.5 for many years.Last December,He authored by a report,If the 2012 Beijing/Shanghai/guangzhou/Xi 'an four urban air quality compared to the 2010 did not improve,Because of PM2.5 pollution"Excess death"There will be 8572 people,With the economic loss from the 6.8 billion yuan RMB.

　　这个数据被很多人误读为“PM2.5致8000人死”，事实绝非如此。

This data is a lot of people to read"PM2.5 to 8000 people die",This is simply not the case.

　　潘小川告诉中国青年报记者，其研究并非一一找到8000多名死者，而是用环境流行病学的通用方法测算得来，“我们使用了这几年死亡率的数据和污染物的数据，排除了其他变量。这还是保守估计。”

PanXiaoChuan told China youth daily reporter,The study was not found by more than 8000 dead,But with the environment of the epidemiology of general method to calculate the management it,"We used this years mortality data and pollutant data,Ruled out the other variables.This is a conservative estimate."

　　是否存在难以统计的变量，导致人们找错“杀手”？潘小川说，由于空气中的臭氧和黑碳情况难以统计，因此无法完全排除变量对结果带来的影响。

Whether there is difficult to statistical variable,Leads people to choose the"killer"?PanXiaoChuan said,Due to the ozone in the air and black carbon situation difficult to statistics,So we can not completely ruled out the effects of variables on the results.

　　事实上，大部分流行病学的数据都是用相似的办法推断而来的。这些数据的目的是提供概貌，尽可能地为决策提供方向，却无法让人们一窥真相，更无从得知，一窗之隔的雾霾和自己的身体机能发生了的怎样的关系。

In fact,Most epidemiological data are in a similar way to deduce the.The purpose of these data is to provide general view,As much as possible to provide direction for decision-making,But can't let people see the truth,clarity,A window between fog haze and his body function for the what kind of relationship.

　　对PM2.5的毒理学研究试图从微观层面找证据。北京大学环境科学与工程学院教授朱彤2004年就曾进行过“沙尘暴颗粒物对人肺成纤维细胞的细胞毒性研究”，同时开展的还有对这些颗粒物对大鼠肺泡巨噬细胞的影响研究。

To PM2.5 toxicological study attempts to find evidence from microcosmic Angle.Peking University environmental science and engineering college professor ZhuTong 2004 went through"Sandstorm particles on lung fibroblast cell toxicity research",At the same time also to carry out of these particles to rat alveolar macrophage influence research.

　　上述实验采集位于北京市城区交通干线旁的PM10和PM2.5，将颗粒物处理后，分不同浓度作用于细胞24小时。得出结论是，“当（染毒）浓度达到每毫升20微克时，（细胞的）线粒体琥珀酸脱氢酶活力下降51.91%和44.00%。”

The above experiment acquisition in downtown Beijing traffic trunk side of PM2.5 and PM10 readings - which were taken,After processing the particles,Points of different concentration effect on cell 24 hours.Conclusion is,"when(infected)Concentration per ml and when micrograms,(cells)Mitochondrial succinate dehydrogenase activity decreased by 51.91% and 44.00%."

　　不过，实验室中设定的浓度，以每毫升微克为单位，而目前衡量空气中PM2.5含量的浓度，是以每立方米微克为单位，两者相差甚巨。人们关心，实验室环境如何与现实中的昏黄空气对接？

but,The concentration of the laboratory setting,Per milliliter micrograms of for the unit,And at present measure air PM2.5 levels of concentration,Is for the unit per cubic meter of micrograms,Both differ greatly.People care about,How the lab environment and the reality of pale yellow air butt?

　　朱彤告诉本报记者，流行病学是“知其然”，毒理学试图“知其所以然”。动物学的实验主要是为了找出原因，其剂量设定只是为了观测急性效应，难以与实际无缝对接。

ZhuTong told our reporter,Epidemiology is"Law concering",Toxicology trying to"Know its a torrent of".Zoology experiment is mainly in order to find out the reasons,The dose set just for observation acute effect,Is hard to meet the practical seamless docking.

　　也就是说，这些研究目前都无法回答最直接的提问：“在今天这样的空气中，一个人走出门去，究竟要承担多大风险。”

that,These studies are currently unable to answer the most direct questions:"In this air,A person walking out the door to,What to take how much risk."

　　人们对这些悬浮物无从选择。

People on these suspended matter have no choice.

　　国家室内环境与室内环保产品质量监督检验中心主任宋广生是室内环境方面的专家，他告诉记者，和室外的污染相比，室内的PM2.5也不容忽视，做饭的油烟和抽烟的烟雾，都会拉升室内的可吸入颗粒物污染。

National indoor environment and indoor environmental protection product quality supervision and inspection center director song ansheng is indoor environment expert,He told reporters,And outdoor pollution compared,Indoor PM2.5 also nots allow to ignore,Cooking smoke lampblack and smoke,Will pull litre indoor fine particulate pollution.

　　不过，他现在也处于“两难”境地。“我们平时都建议冬季室内通风，上下午各一次，减少室内的生物和化学污染。但现在窗外情况也不好……那还是，暂时不开窗了吧。”

but,Now he is in"dilemma"situation."We usually have suggested winter indoor and ventilated,The one time in the afternoon,Reduce indoor biological and chemical pollution.But now the window situation is bad...It was,Don't open the window now."

　　如果无法避免出门，有没有必要戴口罩？潘小川告诉记者，虽然PM2.5的危害不可忽视，但和吸烟的危害没法比，“如果按同样的办法计算，因吸烟而超额死亡的人比PM2.5多得多。”在他看来，出门没有必要戴口罩，健康的人在室外暴露一两个小时问题不大。

If you cannot avoid to go out,There is no need to wear a face mask?PanXiaoChuan told reporters,Although the dangers of PM2.5 can not be ignored,But and the dangers of smoking can't ratio,"If in a similar way to calculation,Because of smoking and excess deaths more than PM2.5."In his view,There is no need to go out wearing a mask,A healthy person in the outdoor exposure a two hour isn't a problem.

　　环保志愿者刘昌峰就没戴口罩。他早就开始自发地关注PM2.5，为了解确切的数据，他甚至自己持着仪器各处检测，被媒体戏称为是“我为祖国测空气”。说起PM2.5，他比普通公众熟悉得多。这些天，当很多人为雾霾天纠结不已的时候，他相对平静，“没那么夸张，戴口罩如果挤压鼻腔，导致过度吸入细颗粒物，反而对身体不好。”

Environmental protection volunteers LiuChangFeng didn't wear a face mask.He would have started to spontaneous attention to PM2.5,In order to understand the exact data,He even hold the instrument testing everywhere,By the media nicknamed is"I for the motherland measuring air".Speaking of PM2.5,He is more familiar with the general public.These days,When many people fog haze days ravel at the time,He relatively calm,"Not incredibly,Wear a face mask if extrusion nasal cavity,Lead to excessive intake of fine particles,But bad to the body."

　　不过，他坚持让自己的孩子留在家中，还买了空气净化器。白雪

but,He insisted that their children at home,I also bought air purifier.Snow White