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北京的“蓝天”掩不住健康风险

安 雪峰

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安雪峰对美国使馆推特数据的分析显示,中国的空气质量评定存在严重的问题。更严格的标准正在酝酿之中,但官方恐怕仍难直面北京空气污染带来的健康风险。

article image
 

尽管光化学烟雾问题悬而未决,但北京官方仍然宣称,过去两年中这座城市的空气质量达到二级良好以上的天数达到80%。不过,美国驻华使馆屋顶上的检测仪却给出了截然不同的答案:超过八成的时间里,北京的空气污染达到了足以影响人体健康的程度,而空气质量达到“有害”水平的天数也远远大于“良好”的天数。世界上很多国家都有空气质量报告制度,但却没有哪个国家像中国这样把“轻度污染”说成是“一级优”。

从某种意义上说,这种差异是由于中方的统计过于简单。北京政府虽然将细颗粒物和臭氧列入了监控指标范围之内,在每日空气质量报告中却对这两种能造成肺部疾患和寿命缩短的污染物只字不提。而另外一方面,中外空气污染报告的差异是政府干预的结果:

图1.

1 美国将PM2.5纳入空气污染项目。 2 根据美国大使馆数据显示,北京在过去两年中PM2.5占PM10浓度值的75%(85.3%)。

美国使馆的评估在北京市民中引发了强烈反响。面对舆论的重压,中国政府宣布了在空气质量报告中加入细颗粒物和臭氧指数的计划,只是这一计划的实施最早要等到2016年。过去两年一半以上(约55%)的天数中,北京市区空气细颗粒物浓度都超过了每立方米75微克的新日均标准,而细颗粒物的年平均浓度更是差不多超标三倍,达到约每立方米100微克。(标准是每立方米35微克)【参见图2.北京空气质量在可接受限度内?(PM2.5)根据美国大使馆监测数据和美国以及北京拟测PM2.5标准显示的空气质量达标天数百分比(2010.01-2011.10)】。但在新的监测体系中,必定会有很多具有误导性的描述得以保留,甚至变本加厉。

图2.

颗粒物是北京空气质量报告中最引人关注的主要污染物。空气中漂浮的微小固体颗粒大小不同,对人体健康的影响也有差异。根据中国现行的空气质量指导标准,即便空气质量为“一级优”,可吸入颗粒物(PM10,即直径等于或小于10微米的颗粒物)含量也有可能超过世界卫生组织空气质量准则的2.5倍。就算中国开始报告细颗粒物(PM2.5)含量,高于世卫组织标准3.5倍的细颗粒物水平仍然在“一级优”的范围之内。在美国被认为是“中度污染”的PM 2.5浓度在中国也是“一级优”。【参见图3. 拟实施的中国每日PM2.5报告指标及美国目前使用的标准】

图3.


美国使馆每天通过Twitter发布的空气质量检测结果不仅成为了人气极高的手机应用软件,更是新浪等微博用户的转发热门。虽然这份时常警告“北京空气污染严重”的报告多次在媒体中出现,但从没有哪篇报道像本文这样认真讨论过美国使馆测算的每日平均污染浓度数据。美国使馆的监测时间与北京环境保护局相同。

美国环境保护署核准的PM 2.5评估方法是基于24小时平均值的,因此美国驻华使馆每小时一次的数据发布其实存在着夸大北京污染严重程度之嫌。例如在今年前十个月中有57天,美国使馆方面都发布了至少一条“有害”程度污染警告。但是按照日平均数据判断,PM 2.5浓度达到“有害”级的只有17天。即便是这些天的空气质量算不上“有害”,仅仅是“很不健康”。

北京市环保局副局长杜少中认为,北京空气质量近年来有所改善是“不争的事实”。在中国,空气质量达标天被称为“蓝天”,通常用空气质量“一级优”和“二级良”来表述。官方的数据显示,蓝天数已经由1998年的100天(占全年的27%)提高到2010年的286天(占全年的78%)。

但这种改善的背后是空气质量监测和报告制度中的不规范,而不是空气质量的切实提高。最重要的是,政府两次更改了监测站的地点。2006年,北京市政府关闭了当时两个空气污染最严重的监测站,2008年又将监测站搬到六环以外,远离市中心15到20公里的地方。政府方面至今仍受益于这样的调整,不仅蓝天数增加,空气质量报告中的污染浓度也显著下降。如果不是因为此前的监测站地点变化,2010年的蓝天数至少要比报告少71天。(多出的这71天中,55天来自2006年的调整,16天拜2008年的迁址所赐。)【参见图4. 排除2008年增加监测点,2010年的蓝天数中有16天已超出标准(指数<=100)。若排除2006年检测系统的改变,另约有55天超标。】另外,北京市政府2002年起停止发布每日臭氧水平报告。

图4.

1关于监测标准,请参阅安雪峰2008年发表的环境研究报告书《空气质量标准自相矛盾:北京的蓝天数和PM10浓度》。2006年新增监测点使得报告中可吸入颗粒物PM10每立方米浓度下降到12微克,2008年新增监测点更是使得这一数值下降到每立方米4微克。若无新增监测点,2010年蓝天数及年均PM10浓度则与8年前相似。2010年,官方报告中蓝天数为286天,年均PM10浓度为121微克。若无2010年新增的监测点,蓝天数则为215天,年均PM10浓度为137微克。2003年,蓝天数为224天,年均PM浓度为141微克。

中国科学院自行监测的结果显示,过去的十年中,北京的PM 2.5浓度实际上以每年3到4个百分点的幅度增加。 PM 2.5能进入人的肺脏和血液中,因此也被认为是对人体健康伤害最大。

就在官方一如既往地将对人体健康极其有害的空气污染冠以“二级良”美名之时,中国环境保护部官员别涛两周前在北京表示,公众意见将于近期列为“评定地方政府环保工作”的标准之一。尽快认识到污染的严重性,以及公众和媒体受误导的程度已经越来越成为中国政府部门的重要任务。

数据与方法

美国使馆第一次报告北京空气质量和污染浓度是在2008年,当时只是作为面向员工的内部参考。为了撰写这篇分析文章,我专门下载了美国使馆2010年1月到2011年10月底的在Twitter上发布的全部空气质量数据存档,并与北京市环境保护局的数据进行了比较。我将官方报道的空气污染指数换算成可吸入颗粒物浓度,并将其与香港欧盟使用的空气质量报告制度相比较。我还根据美国使馆的每日监控数据计算出PM2.5的年均浓度以及PM2.5与PM10之间的比率。

此外,我还将美国使馆的数据与中国新出台的细颗粒物每日和年度标准进行了对比。由于数据并不完整,日浓度数据仅涵盖了这22个月中88%的时间段,而我也仅对北京市环境保护局和美国使馆都发布报告的天数进行了分析。(美国使馆方面拒绝向我提供其余数据,并称数据不完整是期间检测仪器维护造成的。)

美国使馆的数据有两点引起了我的注意:一是它不能代表北京市整体的空气质量水平——美国使馆的网站上也提到了这一点——再则就是北京环保部门提出的,这些数据并不准确。不过,虽然美国使馆所在的朝阳区空气质量并不能代表北京全市,但这一地区的空气质量历来都要高于北京市其他地区。的确,大多数国家都会用最差的数据判断整体的达标情况,但是也不是像北京这样用一个精挑细选的样本做标准。实际上,北京曾在1998年报告过每个监测站的污染物年平均浓度。但也仅仅持续了一年,并且之后再也没有过。

另外,美国使馆使用的BAM2010型细颗粒物监测仪是美国环境保护署认证的唯一一种在美国境内监控PM2.5浓度的颗粒物连续监测仪。如果这种仪器能用来衡量美国空气质量的达标程度,那它至少也能用作对北京的空气污染水平的初步评估。

北京环境保护局称,外国使馆发布的数据不应作为判断空气质量好坏的标准,况且美国使馆的数据有夸大其辞之嫌。但需要明确的是,美国使馆的分析之所以有必要,正是因为北京环境保护局对其监测的细颗粒物浓度隐而不宣。而对于美国使馆来说,改每小时更新为每日浓度监测或许可以使其数据更有说服力。

研究结果

我的研究表明,对颗粒物浓度的误导性描述极大地影响了对北京空气污染严重性的认识。对污染物浓度的描述能在一定程度上左右公众对于污染问题严重程度的看法。【参见图5. 北京日常污染等级彩色条形图(PM10)。以下分别为美国大使馆、欧洲和香港PM10标准下测得的结果。2010.10-2011.10】

图5.




即便中国现行空气质量评定标准修改之后,它仍然无法不折不扣地反映真实的空气污染水平。根据计划中的新评定标准,北京空气质量优良天数约占全年的45%,但美国使馆发布的每日报告显示,实际数据仅为全年的3.5%。【参见图6. 北京日常污染等级彩色条形图(PM2.5),分别根据美国大使馆数据和拟实施的中国标准测得。2010.10-2011.10】

图6.
 

官方报告中,北京过去两年空气质量优良的天数几乎达到了80%。但其中八成天数的PM 10水平若放在香港或是欧盟,一定会被评定为严重污染甚至更糟。【参见图7】以上两个地区的空气质量评定标准与美国相似,而美国使馆基于独立PM2.5监测作出的空气质量报告也表明,北京超过八成天数的空气污染程度都高于美国的安全标准。美国环境保护署近日还提出要大大提高其PM 2.5标准。

图7.




美国使馆监测到的过去两年北京PM 2.5浓度数据平均约占北京市环保局PM 10浓度的85%。美国使馆报告的过去两年北京年均PM 2.5浓度约为每立方米100微克。

接下来呢?

大多数人对“蓝天”和“污染指数”这样由政府创造出来的新名词并不感兴趣。人们关心的是污染对他们健康的危害,这才是最重要的事。正如《中国日报》近日一篇报道中写道:“当所有市民都意识到空气质量存在问题时,遮遮掩掩不能解决问题,不如直面批评。”即便官方如期修改评价标准,中国的空气污染问题仍不能得到充分的反映。

新标准规定的年均PM 2.5浓度为每立方米35微克,北京过去两年每立方米100微克的年均PM 2.5浓度是新标的近三倍。这接近已经公布的2000年北京空气质量数据,是世卫组织每立方米10微克的空气质量准则的整整十倍。相比之下,美国空气污染最严重的城市洛杉矶2010年的细颗粒物年平均浓度也只有每立方米15微克。在近期发布的一份对全球500个城市的调研中,蒙古、马达加斯加、科威特和墨西哥的城市被世卫组织列为PM 2.5浓度最高的地区,但这些地区的污染数据也不过是北京的二分之一。

阿登·波普等人2009年发表的关于污染对健康影响的权威研究发现,一个城市的每立方米细颗粒物浓度降低10微克,其人口预期寿命就可以延长0.6年。照此看来,如果北京的细颗粒物浓度能达到洛杉矶的标准,北京居民的平均寿命就能提高五年。早在1999年,朱镕基总理曾说他担心自己会因为北京的空气污染而折寿至少五年。不过细颗粒物的浓度到现在也没有得到改善。

北京政府应该立即公开并准确描述城市空气污染的状况。作为第一步,政府应该停止那种将有害水平空气污染说成是空气质量“良好”的错误做法。既然已经监测了空气中细颗粒物和臭氧的浓度水平,就应该如实地向市民公布。每一份名不副实的“蓝天”报告都在传达错误的信息:这不仅误导了北京市民,也阻碍了城市空气质量的真正改善。

安雪峰是一名环境顾问,现居北京。他曾在普林斯顿大学攻读地球科学,近期又获得了加州大学洛杉矶分校的法学博士学位。2006年至2007年期间,他曾以“普林斯顿在亚洲”项目成员的身份来到北京,并开始研究中国的空气污染问题。 

翻译:李杨

图片作者:安雪峰
主页宣传图片作者:onekell

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不同标准

很多发展中国家的标准都达不到特别严格,达不到发达国家标准,一是没有能力治理污染;二是没有动力;普通大众既然没有特别的反抗,也被官方数据蒙蔽,就凑合凑合了。因此公民社会在其中的作用不可小视,推动政府作为。

Different standards

Standards adopted in many developing countries are not particularly strict, not on the same level as in developed countries. Firstly, these countries don't have the capacity to reduce pollution; Secondly, there's no incentive to do so, (in the sense that) the public, being deceived by official data, normally don't pressure to do otherwise. Therefore, the civil society is playing a considerably important role in pushing for government's action.


谢谢,bingo

我同意社会在推动空气质量标准以更好地保护公众的事情上可以扮演很重大的角色。但是,我认为对问题的严重性和影响的保守态度,不管是从短期的角度还是长远的角度看,直到现在一直都阻止着中国公众扮演该角色。中国确实有能力以最小的代价减少显著的空气污染,污染对健康的影响远比这些代价重得多,而最重要的问题之一就是中国缺少行动来执行现有的排放标准。

Thanks, bingo

I agree the society could potentially play a large role in pushing for air quality standards that better protect the public. However, I believe the understatement of the severity and effects of both short and long term pollution levels has, until recently, prevented the Chinese public from being able to take this role. China does have the capacity to significantly reduce air pollution at minimal costs that are far outweighed by the health impacts, but one of the significant problems is lack of enforcement of existing Chinese emissions standards.

2008奥运和2012奥运

你为什么不讲一下北京在奥运会期间所做的努力呢?这些努力在随后几年都取消了。说中国因为奥运会更关注其产生的污染问题、在围绕《京都议定书》的谈判中立场更灵活,这是个谎言。

Olympic games of 2008 and 2012

Why don't you tell any story on the efforts done by the Beijing city during the week of the Olympic games? Those efforts have been cancelled in the following years. It has been a lie that China awarded by the olympic games would be more conscious of the pollution it is generating and more flexible in the worldly talks around Kyoto.


与生俱来的粉饰

我并不认为北京实施新空气质量检测标准就足以推动污染治理的实际行动。根本问题在于导致污染的经济行为被认为比市民安全更重要。

污染治理被视为拖经济后腿,而非正面的、重要的、且必须的行为。这个秋天的雾的确很糟。一个目击的飞行员发布了十一月拍摄的这些照片:http://www.ab9il.net/avgallery/china-smog.html

向更清洁能源、更清洁供暖以及更绿色生产的转型是一件好事!如果领导人的观念能够改变,中国完全可以骄傲地带队。(中国的)人民应该比现状更好。

Designed to Whitewash

I do not believe the new standards, when applied to Beijing air quality measurements, will prompt action to clean up the pollution. The bottom line is that the economic action causing the pollution is deemed more important than the citizens' safety.

Cleaning up is seen as an economic drag and not something positive, important, and necessary. This autumn's smog has indeed been bad, and was noticed by a pilot who posted these photos, taken in November:
http://www.ab9il.net/avgallery/china-smog.html

Converting to cleaner fuels, cleaner heating, and greener manufacturing is a good thing! China could lead with pride if the bosses had a different opinion. The people deserve better than today's situation.


作者不太象真正的专家,有危言耸听的嫌疑

有很多常识性的问题:
1.每个国家都是根据自己的发展阶段和实际情况来制订空气质量标准。因此,WHO提出了指导值和不同的阶段目标,各国根据自己可达的目标来制订自己的空气质量标准。

2.许多国际研究表明,PM2.5与PM10之间的比例关系在50%左右,因此WHO在制订其空气质量指导值的时候,PM2.5取值为PM10值的一半。不知道北京的PM2.5占PM10的85%这个数值是怎么得来的。作者自己做过研究吗?

不知道作者是怎么研究中国空气污染的,自己做过实验吗?那个数据是自己得来的?东平西凑的数据可不能用来下结论的啊。

The author does not appear to be a real expert, and I have suspicions that he is simply an alarmist

There are many common-sense errors:
1. Previously, air quality standards have always been drafted on the basis of the level of development and the real situation in each country. As a result, the WHO has given guidance indices for different stages of development, and each country can draft their own air quality standards based on the aims they can achieve.

2. Research in many countries has shown that the proportional relationship between PM2.5 and PM10 is around 50%, so the WHO has defined the value of PM2.5 as half of PM10 when drawing up air quality guidance indices. Has has the author done research on his own?

I don't know how the author researched air pollution in China- has he carried out his own tests? That data has been obtained by himself? Information with no basis can't be used to draw conclusions.


认识什么是主观和客观

标准是人制定的,但是空气污染及其危害是客观存在的。不管你用什么标准,污染和危害都会在那里。

就算是发展中国家和发达国家标准不同,但是污染的危害会不同吗?发展中国家会因为自己的发展程度而获得更小的污染危害吗?

所以那什么发展程度不同,标准不同的人需要想想标准是干什么用的。

Learn the difference between objective and subjective

Standards are drawn up by people, but the existence of pollution and the harm it causes can be shown to exist objectively. No matter what standards you use, the pollution and harm are still there.

Even if the standards in developing countries and developed countries are different, does that mean the harm caused by pollution is any different? Do developing countries sustain less harm from pollution as a result of their level of development?

So people who think that standards should be different for countries in different levels of development need to think what these standards are used for.

基于北京政府数据的分析

你好,dlming。我在我的文章中指出了我所列数据的两个主要来源:1)24小时日均PM2.5浓度,使用BAM 1020 FES PM2.5过滤器,位于朝阳区美国大使馆楼顶;2)公布的日均空气污染指数值,由北京市环保局公布,这些数值用政府的算法转换成了PM10的浓度。
就一般的空气质量标准和专门的公开报告而言,如世界卫生组织(WHO)建议,两者在绝大多数国家中是设计“用以保护公众健康的”。《2005年世界卫生组织指南》已颁布近七年,其中清晰地指出,“实现指南中规定的参考值应该是所有地区空气质量管理和降低健康危害的终极目标。” 即使是七年前也很清楚,“对健康的不利影响范围不断扩大,这与含更微小颗粒物的空气污染有关。”
在北京PM2.5与PM10的比例出奇的高,达85%。如世界卫生组织指出的:“在设置地方标准时,假设相关数据有效,可以采用与此比例不同的数值,如果该数值能更好地反应当地的情况。”这也是中国标准和报告弱化空气污染的健康影响的另外一个原因。按已过时的《世界卫生组织2005指南指南》,我取年均PM2.5浓度为35ug/m3,那么暂行的年均PM10浓度的指导数值就是其两倍即70ug/m3。然而,因为在北京PM2.5至少约是PM10的85%,年平均PM10浓度约为41ug/m3就能达到世界卫生组织暂行指南的1级标准,这只是一个临时的数值,应该会设立新的标准。然而,中国目前年均PM10标准是100ug/m3,这远比世界卫生组织1号暂行指南规定的75ug/m3高的多,正如你所指出的,这个数字基于假设的50%比例,对北京来说是不准确的,那里PM2.5构成了PM10分数里分子的很大一部分。

Analysis based on Beijing government data

Greetings dlming, I identify in my article the two main sources of my data: 1) 24 hour daily average PM2.5 concentrations as measured by the BAM 1020 FES PM2.5 filter atop the US Embassy in Chaoyang, and 2) publicly reported daily average air pollution index values, reported by the Beijing Environmental Protection Bureau, which are the converted into PM10 concentrations based government methodologies.

In terms of air quality standards, generally, and public reporting, specifically, they are designed in most countries, as the WHO reccomends, "to protect the public health." The WHO 2005 guidelines, which are now nearly 7 years old, make clear that "[p]rogress towards the guideline values should [...] be the ultimate objective of air quality management and health risk reduction in all areas." Even back then it was clear that "an increasing range of adverse health effects has been linked to air pollution, and at ever-lower concentrations."

The ratio of PM2.5 to PM10 in Beijing at .85 is shockingly high. As the WHO notes: "When setting local standards, and assuming the relevant data are available, a different value for this ratio, i.e. one that better reflects local conditions, may be employed." This is yet another reason why the Chinese standards and reporting understate the health impacts. ie the now dated WHO 2005 interim I target annual average PM 2.5 concentration is 35ug/m3 and the annual average interim PM 10 concentration guideline is twice that at 70ug/m3. However, because in Beijing at least, PM2.5 is ~85% of PM10, an annual average PM10 standard of around 41ug/m3 would consistent with the interim-1 level WHO guidelines, which should be temporary until higher standards are set. Yet, currently the Chinese annual average PM10 standard is 100 ug/m3. This is far more than the WHO interim I guideline of 75ug/m3, and as you note, this number is based on an assumed ratio of 50% which is inaccurate for Beijing where PM2.5 constitutes such a large fraction of PM10.

出色的研究

祝贺史蒂夫提供了如此详尽的数据考察。数年来我一直在博客上谈论这件事情并传播美国大使馆的反馈,但我也一直期待有人可以真正地处理分析这些数据来做比较。这是目前为止我在这个议题上看到的最充分的研究文章,我已经将它作为必读文章转发给其它朋友。

Outstanding research

Steven, congratulations on providing such a thorough examination of the data. I have been pushing this issue on my blog for years and promoting the US Embassy's feed, but I've always hoped someone would actually crunch the numbers for true comparisons. This is by far the most researched piece I've seen on this issue, and I am already forwarding it to others as a must-read.


感谢您的评论

如果您有任何疑问,请让我知道。

Thanks for your comments.

Please let me know if you have any questions.


澄清数据?

史蒂文,我希望你能澄清一些要点:

1。你能更具体地阐述一下,过去2年美国大使馆的平均PM2.5的数值是在100微克吗?每年的确切数字是多少?你是如何计算这个数据的 ——我假定您从24小时的Twitter记录中,取每个中午的平均值?

2。死亡率的问题始终是一个巨大的问题,我在北京诊所的病人总是问我。你说洛杉矶的“预期寿命可能增加超过5年”。能请你澄清:在波普的研究中,他跟踪记录研究对象多少年?换句话说,这个5年的结果,是根据20年的数据,还是8年的数据而得来的呢?你是怎么计算出这个效果?不要忘记,即使波普说肺癌的影响是线性的,但心血管疾病的影响却是非线性的,并且是变平的。你能带我们好好理清一下你的计算吗?

3。还有一个类似的说明,这些死亡率估计是“长期的”。你能推断这个中期或短期的时长吗?如果有人在北京一年一年地生活,他们的死亡率增加的几率有多大?如果你不知道,你见过的最合适的数据是什么?

Clarify the data?

Steven, I'm hoping you can clarify some points:

1. Can you be more specific as to your claim that US Embassy's average PM2.5 is 100 ug/m3 for the last 2 years? What's the exact number for each year? And how did you tally this data -- I assume you simply took the 24-hour Twitter results from each noontime and averaged it?

2. This issue of mortality is always a huge question my patients always ask me in clinic here in Beijing. You state "life expectancy may increase over 5 years" compared to LA. Can you please clarify: in Pope's study, how many years had he been tracking people, in other words was this 5-year effect noted after 20 years of data, 8 years, etc? And how did you calculate this effect? Don't forget that even Pope mentions that lung cancer effect is linear, but cardiovascular effect is NON-linear and flattens out. Can you walk us through the math you did?

3. And on a similar note, these mortality estimates are "long-term". Can you extrapolate this data to medium or short-term stays? So if someone lives in Beijing for a year-year post, what is their increased mortality risk? If you don't know, what's the best data you've seen on this?

流行病学研究和健康风险

谢谢你的提问。但是很不幸,就像你意识到的那样无论是长期还是短期北京如此高浓度的PM2.5还是存在很多不确定的东西。
1)10月10号到10月11号的24小时平均PM2.5浓度是大约102。去年平均PM2.5浓度是大约105,而今年前10个月是大约99。然而,去年的数据很可能有一点高(不会高太多)因为年初的数据丢失了,而且年初的浓度可能比较低。同样,我相信今年的平均浓度结果会高一些,如果包括11月和12月的话。注意,比如在美国,制定PM2.5标准的时候是基于三年的平均值,甚至同一区域检测器的数据也会相差几个百分点。
2)请注意我这里用了“可能增长”这个词。发表在《新英格兰医学杂志》的蒲伯的研究(http://www.nejm.org/doi/full/10.1056/NEJMsa0805646#)用的方法是基于美国51个不同地区5年的平均PM2.5数据,分别是从1979年到1983年,以及1997年到2001年。即使在1979年到1983年这个时间段美国的最高PM2.5浓度也只有大约30。因此,类似科恩等所作的具有影响力的研究(已经发表)http://ehs.sph.berkeley.edu/krsmith/Publications/Chapt%2017%20Urban%20outdoor%20air.pdf 把城市最高浓度PM2.5设为50。尤其是有详细分析估计北京80%以上的区域暴露在交通污染源附近http://www.healtheffects.org/International/Jerrett_Asia_Traffic_Exposure.pdf 我推测在这个水平以上可能有一些影响(部分取决于机动车排放的事实)。其他研究也发现年平均PM2.5浓度降低10ug/m3,人的寿命可以增加几个月到一年(芬兰研究发下PM2.5每增长10,人均寿命就会下降1.3年)。《新英格兰医学杂志》发表的Krewenski 的社论说PM2.5每下降10ug/m3,人均寿命就会增加0.77年。http://www.nejm.org/doi/full/10.1056/NEJMe0809178 因此,我相信从蒲伯和其他人的研究中可以得出一个合理的结论,就是如果PM10减少85ug/m3,人均寿命就会增长5年以上,不过也承认可能存在一些不确定性。(0.77乘以8.5等于6.5,但由于上面描述的哪些因素我说可能增长5年以上,这个说法和文中提到的朱镕基的评价类似)。
3)考虑到明显的不确定性,我觉得不可能使用已经发表的近期数据计算中长期的健康影响。布鲁克等(2010)有关流通的研究http://circ.ahajournals.org/content/121/21/2331.是我读过的最好的研究报告。“尽管理论上的统计风险平摊到所有个体,但由暴露引起的风险升高在固定人群中的分布是不平均的,即使他们看上去是健康的,例如老年人和已经患有(不能确诊的)冠状动脉或结构性心脏疾病的人群。注意该研究也是基于美国那些目前水平低于中国很多很多倍的地区。HEI的研究http://pubs.healtheffects.org/view.php?id=349相当出色但是无疑在这个领域需要更多研究。我希望将来自己花更多时间在这个领域上。

Epidemiological studies and health risk

Thanks for your questions. Unfortunately, as you are aware there is a lot of uncertainty in terms of both the long and short terms risks from the extremely high levels of PM2.5 present in Beijing.
1) The average of the 24-hour averages of PM2.5 concentrations measured from noon to noon between Jan 10 - Oct 11 is ~102. Last year the average PM2.5 concentration was ~105 and in the first 10 months of this year it was ~99. However, the number for last year is likely a bit high (very likely no more than a couple units) because there is some data missing from the beginning of the year when concentrations were likely lower. Similarly, I believe the average concentration for this year will likely end up higher when Nov and Dec are included. Note in the US, for example, attainment of the PM2.5 standards is based on a three-year average, and then even monitors co-located in the same location will vary by up to several percent.
2) Note that I used the language "may increase". The Pope study published in the New England Journal of Medicine http://www.nejm.org/doi/full/10.1056/NEJMsa0805646#Methods was based on 51 municipal areas in the US using average PM2.5 data from the 5-year periods 1979-1983 and 1997-2001. Even in the 1979-83 time period the highest PM2.5 concentrations in the US was ~30. Therefore, some studies such as the influential Cohen et al. (which was published beforehand) http://ehs.sph.berkeley.edu/krsmith/Publications/Chapt%2017%20Urban%20outdoor%20air.pdf set the maximum city-specific concentration of PM2.5 at 50. Especially as detailed analysis has estimated that likely over 80% of Beijing is exposed to near-source traffic pollution http://www.healtheffects.org/International/Jerrett_Asia_Traffic_Exposure.pdf I reasoned that there may be some effect above these levels (in part due to nature of vehicular exhaust). Other studies have found increased life expectancy from several months to over a year per decrease in annual average PM2.5 concentration of 10ug/m3 (Finland study found decrease in life expectancy of 1.3 years from PM2.5 increase of 10). The Krewenski editorial in NEJM describing the Pope study stated a .77 year increase in life expectancy per a decrease in PM2.5 concentrations of 10ug/m3. http://www.nejm.org/doi/full/10.1056/NEJMe0809178 Therefore, I believe that a reasonable conclusion from the Pope study and other research is that life expectancy may increase be over 5 years with a decrease in PM10 concentrations of over 85ug/m3, but admittedly there is considerable uncertainty. (.77 multiplied 8.5 = 6.5, but for the reasons described above I used the phrasing may increase by over 5 years, which is similar to Zhu Rongji's comments included in the text).
3) Given the significant uncertainty, I don't believe that it possible based on research that has been published to date to calculate the health impacts from medium or short term stays. The Brook et al study (2010) in Circulation http://circ.ahajournals.org/content/121/21/2331.full is one of the better studies that I have read. "Despite theoretical statistical risks ascribed to
all individuals, this elevated risk from exposure is not equally distributed within a population. At present-day levels, PM2.5 likely poses an acute threat principally to susceptible people, even if seemingly healthy, such as the elderly and those with (unrecognized) existing coronary artery or structural heart disease." Note that this study is also based in the US where present-day levels are many, many times lower than currently found in Beijing. The HEI research http://pubs.healtheffects.org/view.php?id=349 is quite good but more research is definitely needed in this area. I hope to spend more time in the future conducting research in this area.

杜少中 (北京环保局12月6日)(微波转发)

杜少中 (北京环保局12月6日)(转发):这是几年前的话题,里面要说太多。我只建议你客观的看这个文件,就不难发现一些显而易见的问题,其他可慢慢讨论。提示一下:一,北京空气质量达标天1998年以来一直没有达到超过80%。二,颗粒物年日均浓度也从来没有达到国家标准。

Du Shaozhong (Beijing Environmental Protection Bureau 6 December) (Weibo Repost)

Du Shaozhong (Beijing Environmental Protection Bureau, 6 December) (reposting): This is a topic that has been around for a few years, and there is much on it that I wish to discuss. I just recommend that if you look at this article impartially, you can clearly see the problem, the rest can be discussed more slowly. Let me present this: first, since 1998 Beijing's air quality has failed to come up to standard 80% of the time. Second, yearly and daily average particulate matter concentrations have never achieved the national standard.


请帮忙,我需要北京空气质量数据

你好,Vance:

我们工作室最近发布了一个“北京空气污染指数”的应用(http://itunes.apple.com/cn/app/id477700080?mt=8),这个应用挺受欢迎。
现在我们打算更新一下这个应用,添加历史数据的查询,但是我们在北京空气检测中心的推特页面上和其他地方都找不到2011年7月28日之前的数据。

你可以帮我找到这些数据吗?

如果可以的话请在此回复我或者给我发邮件[email protected]

多谢。

need help for AQI data of Beijing

Hi, Vance
Our studio recently released an app -- "北京空气污染指数"(http://itunes.apple.com/cn/app/id477700080?mt=8), it is warmly welcome by many citizens.
Now we plan to update it with some historical statistics function, but we could find more earlier data before 2011-7-28 on twitter @BeijingAir or any place else.

So could you please help us about the data?

You could either reply me here or email to [email protected]

Thanks.


数据共享

这些数据可以直接下载,但是如果谁下不到,我可以分享一个xls.格式的表格。

Data shared

The data is straight-forward to download, but I am happy to share the data in an xls format if anyone has trouble.

美国大使馆的PM2.5测量值

这非常令人奇怪。在我从事空气质量技术与科学研究41年后,在21世纪第二个十年的刚开始的今天,当我看到一份出自史蒂文•安德鲁先生的报告之后觉得很不舒服,安德路先生好像是匆匆一瞥就尽数了解一座大型城市的空气污染问题。

但是,这位自封的专家所面临的第一个问题就是:我们能否确信架在美国人屋顶的监测设备具备所必需的准确度和精密度呢?我们能否确信那些数据表格经得起合理的质疑和推敲呢?这方面,恰恰应该是空气质量监测优先考虑的事情,却被安德路先生一句简单的“这台设备是唯一经过美国国家环保署认证用于监测PM2.5的设备”所带过。我无意于卷入美国国家环保署(该机构负责认证工作)的内部事务。我仅限于自己想指出的是认证并不是绝对的,然而为了有效,设备也必须遵循特定的规范以保证数据的有效性。我担心,在北京,这些规范远没有得到该有的尊重。

以北京的天气条件,空气质量重度污染现象都是在大雾条件下发生。现在,利用β射线吸收法(用于BAM仪器)对颗粒物的监测对水分子具有极高的敏感性,因为水分子中氢元素的质量百分比约为10%。由于水分子中氢的Z(原子序数)/M(分子质量)(氢的Z/M值为1,一般元素的Z/M值都是0.5)值比较高,β射线的吸收率也就高。这也就意味着被检测的颗粒物,如果在采样器的进气通道没有完全的去除水分,PM2.5的读数将会比真正的浓度数值有大幅度的增加。

显然,制造并销售此设备的公司提供了去除水雾的附件装置;然而,并没有提供该装置在不同环境下有关效率的技术信息,例如在北京,颗粒物的物理特性几乎是独一无二的。总之,我强烈怀疑美国使馆屋顶上的监测设备所监测到的PM2.5中含有大量的水雾。但是,我只会在掌握了水雾在监测过程中被有效消除的真实证据后才将重新考虑我的立场。

最后,请您不要援引美国国家环保署的认证与规范。众所周知,美国环保局认证的一款PM10监测仪已在欧洲(当然也在美国)销售了上成千上万台,却被证实具有大量丢失颗粒物的特性,有时这种丢失量大于50%。只有少数人意识到这一点。发现这点后,设备制造商试图用一个昂贵的附属设备解决该问题。这个片段也帮助很多人明白,空气污染监测不是一件容易的事情,解决问题时也并不像问题出现时那么简单,也表明美国的同事们有时也会犯错误。

最后,我相信美国在环境监测技术上所收获的教训意义重大,我们也要看到这个伟大国家在技术和科技发展中积极的一面。然而,一些代表这个伟大国家的人们也应该遵循起码的谦逊,尽管发生在一些国家的事情不那么“伟大”。

当安德鲁先生去除掉围绕在监测仪器周围的雾气,并得出浓度数据的时候,或许我将对这篇的文章剩下的部分做出评论。

伊万•阿里格里尼
环境专家
罗马“La Sapienza”大学
[email protected]
Tel. (+39) 335 462208

US Embassy's PM2,5 measurements

It is very suprising. I've been engaged into the technology and reseaches on air quality for 41 years, on the day of the very beginning of the second ten years of 21 century, I felt uncomfortable as I read a report by Steven Q Andrews, who seems to know the giant city's air pollution well just with a glimpse.

However, the very first problem came to the self-appointed expert is:whether we can guarantee the device atop the US ambessary is qualified as required in terms of accuracy and whether we can secure the statistics and graphs be true against reasonable doubts and deliberations, which is, in priority, taken into account in air quality monitoring and which is prevaricated by Mr. Andrews as the monitor "is the only continuous particulate monitor that the US Environmental Protection Agency allows for PM 2.5 monitoring in the United States". I don't intend to be involved in the internal business of USA Environmental Protection Agency, who take charge of the business of authentication. What I want to say, only in my own opinion, is the authentication is not absolute, but for the sake of effectiveness of the statistics, the devices have to be in compliance with certain specifications. It is my concern that the specifications do not deserve the respect as it should in Beijing.

All the heavily-pulluted phenomenon of air quality in the states-quo Beijing generate under the condition of heavy fog. Currently, the monitoring survey on particulate matters adopting particuleβabsorptiometry is highly sensitive to water melocules, becuase hydrogen accounts for part of a melocule as around 10% in terms of quality. The higer Z(atomic number)/M(melocular weight) (the value of Z/M of hydrogen is 1, while that of common chemical elements is 0.5) of hydrogen in water melocule the higer absorbing rate of particuleβ. This means the value of PM2.5 would increse substantially to be higher than the actual one once the moisture in the particulates detected was not deprived in the entrance of the sampler.

Obviously, the monitor supplier offers the attached de-moisturation unit but without the information on various efficiencies in different environments. Take Beijing for example, the physical features of the particulate matters are almost unique. All in all, I'm strongly doubting the PM2.5 detected by the monitor atop the US ambessy involve large quantity of water mist. Yet, I won't reconsider my stand point of view until I am given the real evidence that the water mist is deprived efficiently during the survey.

Final but not least, do not quote the authentication of USA Environmental Protection Agency and the specifications by it. As known to all, the hundreds of thousands of a model of PM10 monitor approved by the agency been sold in Europe (in US as well, of course) have been proven to be featured with losing particulate matters in large quantity, sometimes the losing is over 50%. Few people were aware of this defect. The manufacturer tried to addressing this problem by adding a extra unit onto the monitor after the exposure of the defect. This episode helps many understand it is not a walk in the garden to do monitoring survey on air pollution either a piece of cake to resolve issues as they occur. As well, this interprets the US fellows would make mistakes sometimes.

Finally, I believe the lessons acquried by the USA on environment monitoring survey are of great meaningful. We have to be aware of the positive aspect of this great nation on the development of techniques, science and technology. Yet, some on behalf of this nation should follow the least spirit of modesty while some events undertaking in some nations are not so "great".

Maybe I would not issue my discussion on the rest of the text until Mr. Andrews got rid of the moisture embracing the monitor and gained the density statistics.

Ivo Allegrini
environmentalist

La Sapienza University in Rome
[email protected]
Tel. (+39) 335 462208


据官方说法,PM2.5浓度上升

你对美国大使馆PM2.5监测数据的准确性提出的疑虑的确合理,但是我认为你太专注这一细节问题以至于忽略了文章的大方面。请注意我在文章里已经说明这只是"初步评估"。

我同意对湿度影响监测和浓度数据的准确性做更具体的分析会有益处,但是对于总体分析和最终结论来说,这种做法并没有必要。请注意,美国大使馆拒绝了我获取数据的要求。作为回应,我向美国国务院提交了一份信息公开法的请愿书,希望他们提供数据,但是目前为止我还在等他们的回复,所以你提议进行的分析目前不具备可行性。

我在文章中提到,据中国科学院的研究院人员所说,北京的PM2.5浓度在过去十年里上升了3%到4%。最近中国政府似乎改变主意又说近年来PM2.5浓度下降了。但是过去两年里美国大使馆检测器得出的平均PM2.5浓度100ug/m3和目前为止已发表的专家评审的PM2.5浓度数据是相一致的。而且,正如我在文章中提过的,美国大使馆附近区域的空气质量在历史上就比北京其他地区好,而不是差。

进一步讲,在你提出有关美国大使馆检测器问题的同时,许多人对中国PM10监测数据的准确性和可靠性也提出了相似的质疑。我个人偏向使用中国政府的PM2.5数据,但是我在文章中也提到北京环保局监测得出的PM2.5浓度数据并没有公开发表,这一事实考虑也使得这种分析成为必要。

如果你能够得到有关北京过去两年里PM2.5浓度的更准确的一套数据,请记得告诉我。

PM2.5 increased according to government

You raise legitimate concerns over the accuracy of the PM2.5 monitor atop the US embassy, but I think you are too focused on this issue and have missed the larger point of the article. Please note that in the article I state that this is an "initial assessment."

In terms of doing more specific analysis regarding moisture levels affecting the accuracy of the monitor and density statistics, I agree that this would be beneficial but I do not think it is necessary for the general analysis done and conclusions reached. Please note that the US Embassy refused my request for data. In response, I submitted a Freedom of Information Act request to the State Department for the data as well, but I am still waiting for a response and so the analysis you propose is not feasible at this time.

As I mention in the article researchers at the Chinese Academy of Science have been quoted as saying the PM2.5 concentrations in Beijing had been increasing by 3 to 4 percent over the past decade. Recently, the government has changed its mind and said the PM2.5 concentrations have decreased in recent years, but the average PM2.5 concentration calculated from the US Embassy monitor over the past two years of 100ug/m3 is consistent with peer reviewed studies of PM.5 concentrations in Beijing published to date. Furthermore, as I mention in the article, air quality in the area around the US embassy has historically been better, not worse, than the rest of the city

Furthermore, while you raise issues with the US embassy monitor, many people have raised similar concerns regarding the accuracy and reliability of Chinese PM10 monitoring data as well. I would have preferred to use Chinese government PM2.5 data, but as I mention in the article the fact that PM2.5 concentrations monitored by the BJEPB are not publicly reported makes the type of analysis that was done necessary.

If you have access to a better data set of daily PM2.5 concentrations over the past two years in Beijing please do let me know.

中国的空气质量

本文很好地剖析了中国的现状。随着PM 2.5标准的推动,他们将更清晰地看到问题的严重程度。世界各地已经发现TEOM(微量振荡天平法)技术被低估了。在技术层面上,更加准确的读数才刚刚取得一些进展,很多测量PM10的系统在几年前被投入使用。

尽管如此,这是迈往正确方向的重要一步,而这种意识带来了如何对抗问题的解决方法。

我想指出,伊万·阿里格里尼先生是空气质量监控设备的制造者。

『本评论已经修正。请注意避免基于个人感情的论断,论证应对事不对人。』

China Air Quality

This is good insight into the current situation into China. As they push forward into the PM 2.5 standard there will be greater visibility into the extent of the problems that they face. With the TEOM it has been found worldwide that the technology undermeasures. There has just been advancements in technology that allow for greater accuracy in the readings and many of the networks measuring for PM 10 were put in quite a few years ago.

However it is a good step forward in the right direction and awareness brings solutions on how to combat the problem.

I would like to point out that Mr. Ivo Allegrini is a manufacturer of Air Quality monitoring equipment.

[This comment has been moderated. Please remember to avoid ad hominem assertions and keep the arguments about the facts, not the people involved]


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