may 5th 2020

are you wondering what the different colors and numbers below mean?

the numbers are the air quality , which is based on a scale from 0 (good) to 500 (bad).the colors correspond to the different health impact categories (good, moderate, unhealthy... hazardous)

unhealthy for sensitive groups
very unhealthy

april 28th 2020
overlapping kernel densities,

back in 2008, when the world air quality project started, all of the existing air quality monitoring stations where based on highly professional and expensive bam and toem technology. this kind of stations are always maintained by professional and highly qualified operators - and this ensures that the output of this station can be trusted.

12 years later, the bam and toem stations still do exist. but with the development of laser scattering technology and low-cost dust sensor, the bam and toem stations are now outnumbered by immense and dense low-cost sensor networks. nowdays, there are just so many of those networks - to name a few: urad, luft-daten, airqo, airbg, opensense, yakkaw, econet, airkaz, ccdc, ambente, green air, etc..

january 10th 2017
introduction to weather and climate,
univ. of arizona ()

a common question asked is why are nitrogen dioxide (no2), sulphur dioxide (so2) and carbon monoxide (co) concentrations always so low and is measuring them useful?

to highlight the importance of monitoring these substances this article is going to explain where these pollutants come from and how to they affect our health and the environment.

to keep things short this article will just focus on no2.

august 10th 2016
introduction to weather and climate,
univ. of arizona ()

it is already several months since the us epa updated its aqi standard for ozone 8 hours breakpoints. this is definitely a positive step towards strengthening air quality in the usa, since the us epa standard was actually among of the least conservative standard for ozone, compared, for instance, to similar standards in india, china or europe!

but more interestingly, recently took a step further by introducing the ozone formula, which allows to use the weighted 8 hours breakpoint standard in place of the 1 hour breakpoint. this change, which the airnow team did not widely communicate to the public, makes quite a change to the way ozone aqi is reported, and this is what we will be looking at in this article.

february 28th 2016
chimborazo mountain ()

during the past months, the world air quality team has been working on analyzing several new air quality forecast models, as well as improving the air quality forecast model demonstrator.

this article will present the latest forecast model demonstrator, which is based on the gridded population of the world (), and which will be applied to analyze the air quality forecast for the northern india region (including bangladesh, pakistan and nepal).

november 5th 2015

a perfect dust storm ()
we have been writing quite a few times about the influence of wind on air pollution, and how strong winds (or, to be more precise, strong ) can help to clean the air in a very short time. but we never had the opportunity to create on a dynamic visualization of this phenomenon, so this is what this article will be writing about.

october 28th 2015


it is almost two months since our colleagues from the have been making an interesting move towards promoting the idea that air quality is as important as any other business within the united nations. they started to invest in this domain, and came up with the excellent initiative to create an open footprint for affordable air quality monitoring stations.

september 20th 2015

this is a small contribution form the world air quality index project to the asmc - asean specialised meteorological centre () during this heavy period of haze in south asia.

september 18th 2015

map overlay process
(attribution: )

we have been recently cooperating with quite a few more epas worlwide. among all the requests which we have had, it is actually to provide a web map service so that the epa themselves can include the real-time air quality data onto the map from their website.

one of the obvious advantages of using such a map web service from us is to benefit from the transboundary data which we are curating, i.e. a world wide air quality information is provided without country boundary limits.

the second advantage is not only that this is a free service, but it is also completely compatible with standard map technologies from google, bing or leaflet, which allows a quick and easy integration with any existing website.

september 6th 2015

the ambient , refered as o3 and also called called ground-level or ozone impacts everyone on earth regardless of the country, as shown on the image on the right .

afternoon ground level ozone concentration in july 2011

(attribution: )

unlike particulate matter (pm2.5), the ground-level ozone is not emitted directly. it is instead produced through a series of chemical reactions that occur in presence of nitrogen oxides, volatile organic compounds, sunlight and high temperatures, as shown on the following visual:

quantifying the impact of this ground level ozone on health is done via the air quality index standard which each countries defines. what is interesting is that half of the world is using a standard based on milligrams measurement, while the rest is using ppb based measurement. but is this really a problem? this is what we will be looking at in this article.

september 3rd 2015

inspekcja ochrony środowiska.
(inspection of environmental protection)

the air quality data for has been available for a while, but we recently got few questions about the aqi scale used by the inspekcja ochrony środowiska, i.e. the regional inspections of environmental protection, and how it differs with the scale used on the world air quality index project. one of them is from sylwia, who asked:

i am confused with all those numbers, and why there is a difference with the numbers shown on the warsaw epa website.

could you please kindly inform me about the source of the data in warsaw and the reliability of the data you provide with?
this is actually a very good question, since, when it comes to data, no one should take data as "granted" (refering to the excellent from on 'own your body's data'). this is also the reason why the world air quality index project exists, i.e. to explain every one how to understand the number behind air pollution.

july 28th 2015
{ widget : feed }

in order to improve the integration of our aqi widgets within external websites, we have developped a new widget api feed. compared to the existing widget feed, this new api feed provides much more flexibility for the integration, but also many more options for customzing the widget appearance.

july 18th 2015

real-time air quality data for is now available for indonesia. 10 stations located in major cities across indonesia are measuring in real-time pm10 pollution.

the monitoring stations are operated by (badan meteorologi klimatologi dan geofisika), the indonesian department of meteorology, climatology and geophysics.

july 16th 2015

the fleurdelisé, flag of quebec.
(attribution: )

the air quality data for and has been available for a while, but we recently got few questions about the aqi scale used in this part of canada. one of them is from marie a., who asked:

i would like to know why the air quality index on your web site is different from the aqi on the montreal's website? do you recalculate anything to meet the us epa aqi standards? if so, how? with what data?
this is indeed a very good question. and we will explain in this article the different scales in use, how the scales compare to each other, and how the convertion can be done.

july 1st 2015

flag of the republic of poland
(attribution: )

thanks to the world air quality index project community, translations for the are now available for the website and web-application. many thanks especillay to the user "airs" for the excellent contribution.

june 8th 2015

guagua pichincha volcano in ecuador ()

beijing citizens do know for long that the best natural way to clean the pollution in the air is strong winds from the north, while winds from the south might, on the contrary, bring more pollution from hebei.

in , ecuador, there is a similar problematic, except that the pollution comes from the active . fortunately, they do not erupt that often, but when they erupt, better avoid being under the the heavy formed by the explosive eruptions (see picture).

june 3rd 2015

it is already a long time since the hong kong epa has updated its air quality index standard from the traditional air pollution index to the so called air quality health index (aqhi), but we never got a change until now to have a deeper look at it, which we will do in this article.

the hong kong epa has actually done an excellent work at explaining how the aqhi is defined, and the information one needs to understand the aqhi is available from their . the most obvious simplification is the change of the traditional 0-500 index into a new simplifed 0-10 range, sub-divded in five health risk categories, as shown below:

low moderate high very high serious
1 2 3 4 5 6 7 8 9 10 10

but there is actually much more than a range simplification: the new aqhi is also introducing the very clever concept of added health risk (%ar), which was originally , in 2007, by a team of four partners from south africa, and first used in .

may 30th 2015

the air quality forecast for south america is now available on the , in parnership with the brazilian centro de previsão do tempo e estudos climáticos (). the forecast can be accessed freely accessed from as well as . the cptec team has done an excellent work at providing a simple and detailled on the underlying concepts used by their forecast model, called (for brazilian developments on the regional atmospheric modelling system). the picture below (from the cptec) is giving an insight on the workflow for their model (source -> transport -> deposition).

may 18th 2015

(attribution: )

the ground ozone air quality index calculation has just been updated to follow the instant cast concept, i.e. to report the pollution right now instead of the pollution from the previous hours. for more information about the instant cast, please refer to this article.

the calculation for the ozone index is now using the hourly reading, instead of the previous 8 hours average, but still applying the same 8 hours aqi breakpoints formula for aqi below 100. the previous for calculating the 8-hour average concentrations is not used any more for instant reporting. above aqi 100, the normal 1 hour ozone breakpoints are used (while before, the aqi above 100 was defined as the maximum of the 1 hour and 8 hours readings).

may 16th 2015

it is already more than one year since the world health organization has released their ' database 2014'. the who team who worked on this project have done an excellent work at gathering the data for so many countries, and putting it all together in a single place accessible for all.

we wrote about it in several of our past articles (like for the air quality or in ), but we never had the chance to look at the different options to visualize their data set. so, this is what we will be writing about in this article.

may 15th 2015
flag of india
(tiranga, तिरंगा)

the indian central pollution control board has recently announced, in april 2015, the publication of india's national air quality index standard (naqi ). all the details on this standard are available from , or from this from indian institute of technology, kanpur ().

this is actually a very important step forward in the air quality world awarness, since the air pollution in each country is very much specific to the country pollution type: for instance because of dust (in arabic peninsula), because of transport (new delhi) or topography (chile).

may 10th 2015

latin america, just like any other continent in our world is facing air pollution. the recent 2014 report by the on ambient (outdoor) air pollution gives some annual mean figures for several cities in latin america. without surprise, the worst scenarios are in asia, but yet, some cities in latin america have high indexes too (see table on the left).

the ranking from the who should however by considered carefully, especially considering the measurement methods used the report can be argued - for instance, for lima, the peruvian epa is arguing that the data from the who is not correct because the samples were not taken in the right places (read this article from for full feedback from several countries). this is actually for this reason that we only publish real-time information on the world air quality project since we do believe than more than ranking, it is the current conditions that are important for the world citizen.

may 2nd 2015
flag of malaysia
(jalur gemilang)

air quality for malaysia has been available for a long time, but unlike other countries, only the composite aqi is provided. the aqi for the individual pollutants such as pm10, ozone ... is not available, which makes the convertion to the us epa scale more difficult.

fortunately, the information about the aqi scale used in malaysia, also known as api (for air pollutant index) is clearly explained in the document ''.

april 28th 2015
the balkan peninsula, popularly referred to as the balkans, is a geographical region of southeast europe. the region takes its name from the balkan mountains that stretch from the east of serbia to the black sea at the east of bulgaria.

many of the countries in the balkans are providing real-time air quality readings. the data for (thrace), and have already been available on the world air quality index project for a long time. today, we are able to roll-out the data for 3 new countries: , and .

april 26th 2015

we had the honor to be invited by from the nasa applied remote sensing training () team to give a presentation about our world air quality index project at the earth observations and tools for air quality applications

april 8th 2015

when talking about air quality, the first countries that comes to people's mind are china and india, and more generally asia. even on the world air quality index project, asia has always been, since the begining, our strong focus (most likely because this is where our hq is located!).

few years ago, in 2012, we decided to extend our scope to cover the other , starting with , and then following with and , . but one of seven continents, namely africa, has been surprisingly lacking behind. we received many inquiries about this lack of data, and one of the last was from said e. who wrote:
thanks for making the world air quality index project site. it gives very useful information.
my only concern is why africa is not considered.
for information i am a moroccan citizen.

march 23rd 2015

strong lapse condition (looping)

weak lapse condition (coning)

inversion condition (fanning)

examples of atmospheric stability ()
in weather prediction, forecast models are used to predict future states of the atmosphere, based on how the climate system evolves with time from an initial state. while the forecast models are quite (and do require strong scientific and engineering capabilities), the science of analyzing those forecast models, and verifying their , by comparing actual empirical observations to predicted values, is quite straightforward.

for the domain of air quality, just like for weather prediction, it is possible to define models used to predict the future set of atmospheric pollution. there are actually , often referred as . and just like weather prediction, the same concept of accuracy analysis can be applied to atmospheric pollution predictions.

march 20th 2015

very often we receive inquiries from users asking about the numbers published on the world air quality index project, and wondering about the difference with the values expressed in other websites. and that's actually normal, since the numbers, also called air quality indexes (aqi), can be very confusing for beginners. the last message we received is the following one:
we have been checking air quality index for the tianjin, china since last year, however we found the data has such a big difference between your website and another official ( one which is stated on yours as well. i am wondering which one can provide more accurate data, as it will affect the decision for outdoor or indoor. please help me with this issue. thank you!
we have been writing quite a lot about this issue before, for instance from , and more recently about the nowcast. but, because we are still getting many questions, we are now writing this article to explain the difference of the aqi scales used all over the world.

march 15th 2015

back in march 2015, we had the chance to meet in beijing several environmental specialists from the us state department as well as the china mission (the famous entity running the pm2.5 monitors in the beijing us embassy).

among all the topics that were addressed, there is one worth writing about, namely the "nowcast" system. this system used by the us epa to convert the raw pollutants readings, expressed in µg/m3 or ppb, into the aqi (scale from 0 to 500). it is used for all the aqi values reported on the website.

the concept behind the nowcast is to compensate the "24 hours averaging", which should be used when converting concentrations to aqi. the reason for this averaging is that the specifies that each of the levels of health concern (i.e. good, moderate,... unhealthy...) is valid under a 24 hours exposure[1]. for example, when seeing a 188 aqi (unhealthy), one need to read it as "if i stay out for 24 hours, and the aqi is 188 during those 24 hours, then the health effect is unhealthy". this is quite different from saying that "if the aqi reported now is 188, then the health effect is unhealthy".

february 23rd 2015

we have just stepped in the lunar new year of the goat (combined with the wood element for 2015), and, for the world air quality index project team, that means full speed working on extending the air quality monitoring to new countries in south east asia. namely: , and (and more, e.g. myanmar and laos, will follow very soon).

as there is also a huge demand for pm2.5 monitoring for (especially chiang mai and bangkok), or for more station in (ho chi minh city), the extension will also cover selected countries with existing network.

but, this time, unlike for the previous countries, we do need the help of everyone, and especially your help if you are living in one of those countries. the reason is that, this time, since the real-time air quality information is not publically available from the environmental protection agencies (epa) of those countries, the world air quality index project will start to crowdsource air quality monitoring stations in the main cities of the above countries1.

visible air pollution on the manilla and jakarta skylines

february 15th 2015

we recentely had the priviledge to start a cooperation with the .; the objective is to use the remote air quality sensing based on the nasa satelites to determine the air quality in areas where sensors are not available (e.g. over the sea, but also for countries where sensors are not yet available).

february 8th 2015

earlier this week (of february 2015), we got several inquries from hanoi citizen wondering about the air quality index which was displayed on the hanoi page ().

the main reason for the inquiry was that the air quality index displayed on the world air quality index project was around 50 (green aqi) level, while the outdoor visibilty in hanoi looked like this:

october 28th 2014


你可以从 下载此应用。如果不能访问google应用商店,你也可以从我们的网站上直接下载 apk文件.

监测站地图: 亚洲
监测站地图: 北中国
监测站地图: 北京
监测站地图: 汉城


october 6th 2014

like every other year since 2002, our collegues from (aka clean air initiative) are organiznig the biennial (). this time, it will take place in sri lanka, from november 19th to 21st 2014, and will be co-hosted together with the environmentally sustainable transport (est) forum.

the "integrated conference of baq 2014 and intergovernmental 8th regional est forum in asia"  co-organized by the , , , , and , in partnership with the , , and .
this year theme is "next generation solutions for clean air and sustainable transport − towards a livable society in asia":
recognizing that clean air and sustainable transport are essential to a livable society in asia, we call for innovative and smart solutions (policy, institution, technology and financing) that significantly reduce air pollution and greenhouse gases from energy, industry, transport, and area sources, and ensure a safe, equitable, environment and people-friendly transport system by accelerating the shift towards more environmentally sustainable transport (est) in asian cities and countries.
check out the . more than 800 participants are expected to join the baq 2014, and we will be part of them, presenting our recent research on we have been conducting within our .

september 6th 2014

the air quality data for and is finally available after a long waiting time: the department of environmental regulation (der) from the governement of western australia, is now publishing the data on their site: . while the link to the is still not working, the feed can be accessed from this new .

august 1st 2014

您可能无意中发现了海尔最新产品“空气盒子”。 可从或 买到。价格是399. 这是的一款产品。 这是海尔“智慧生活”理念的一部分,旨在与智能空调一起使用。

它声称能够同时测量挥发性有机化合物(,即臭氧),和pm2.5颗粒物。 但是他的真实效果如何呢? 要知道答案,请查看我们的最新正在进行的实验有关海尔的airbox连接: 。


july 21st 2014

the windows mobile 8 phone application is now available for download from the microsoft application store:

october 21st 2013

note: this article was written in 2013. while the dylos monitor is still a good product, there is nowdays much better and affordable monitoring products, so we do not recommend purchasing the dylos product anymore.
you can for instance check the product range from es labs.

已经进行50天了。 上周末北京有很强的北风,空气污染降到很低,因此我们利用这个时间作为维护dylos计数器的好机会

原因是,虽然dylos 计数器是精心设计与制造的仪器(我们确实这样认为),但是它或许并不是专门为在北京有时会出现的严重空气污染情况下而设计的。

注意到在空气严重污染的情况下,dylos 与bam 之间的相关图表读数在浓度超过38000以上的差距越来越大后,所以我们决定检查dylos计数器内部的工作情况. 这种饱和现象是由于内部空气不能正常流通引起的严重结果,而空气不能正常流通是由于空气管道饱和后引起的。在空气严重污染的期间, 由于大量颗粒物通过空气管道形成的这种现象是完全正常的。


- 北京的灰尘 可以影响 dylos空气颗粒物 计数器 内部工作 -

照片上的灰尘就是这次清洁的结果。使用一个细小精致的刷子,就可以清理出如此数量惊人的灰尘。这是在室外做了五十天实验后的结果。 照片上的灰尘就是严重污染时空气中悬浮的可被吸入的颗粒物。

- 真实的北京灰尘,北京的人们在空气严重污染时所呼吸的。 -


清洁维护已经过去10天了。从箭头2指示的部分,可以看出清洁前与清洁后dylos 的读数数据与bam的数据已经十分接近了。 尽管清洁维护确实起到了效果,但是在空气污染极其严重的情况下,这种差距还是会存在的(可以比较1与3 部分)。 我们会与dylos公司联系,咨询他们对此种情况的解释与看法。



september 9th 2013

因为一些历史原因,世界空气质量指数项目的网站上一些城市的空气质量指数换算公式没有使用2012 epa 更新的pm2.5 标准 。 仅涉及到亚洲,例如日本,台湾。其他大洲(包括美洲,欧州及大洋洲)则一直使用2012 标准。

与(1999年发布的)前一版相比,2012年12月14日发布的新版epa标准的主要变化是吧pm2.5空气质量指数的每个等级的15µg/m 3 降到了12µg/m3

2013年9月9日以后,所有的 国家都使用更新后的pm2.5 空气质量换算数值范围,如表格所示:

september 8th 2013
测量空气质量最常见的方法,只要是有关pm10 与 pm2.5微粒的检测,就会使用beta衰减检测器(beta attenuation monitors),又叫做bam(请看右侧的图片)。 这些都是专业仪器,也是中国,美国和其他大都数国家官方唯一用来检测空气质量的仪器。最有名的制造商是位于美国的公司。


bam仪器的唯一的主要问题就是它的价格。它的价格预计在12万人民币左右(1万5千欧元)。在中国,目前官方监测站大约有500个bam仪器(平均每个城市 大约有10个监测站)。但是这些还不够,由于还有许多城市不能提供pm2.5读数。在泰国,有21个自动(提供每小时读数的)监测站, 但是却没有一个可以提供pm2.5数据的监测站。在越南,全国只有3个监测站。


因此,在等待全世界各国政府过买更多最新的beta 衰减检测器的时候,有没有别的事情可以做呢?答案是有的!事实上,有一种相对可负担得起的仪器可以用来检测空气质量中的pm10 和 pm2.5的数值。其中最有名的是dylos空气微粒计数器(dylos air particule counter)

如果你想了解更多有关dylos空气微粒计数器的工作原理,请参考 在逆向工程方面杰出的研究,或者直接访问dylos的网站(). 您也可以参考resarch纸 “”来了解测量理论。

note: this article was written in 2013. while the dylos monitor is still a good product, there is nowdays much better and affordable monitoring products, so we do not recommend purchasing the dylos product anymore.
you can for instance check the product range from es labs.


为了证明dylos仪器同样可以用来作为检测空气质量的仪器,我们在我们的实验室里用dylos dc 1100 pro, 带pc接口设置了一个实验。这个专业版的仪器可以在亚马逊上买到,价格是319美元 (1888人民币)。虽然相比之下dylos dc 1100 较便宜些,但是需要注意的是必须要购买专业版的仪器 (pro, 带pc接口),因为它提供一个电脑接口,可以强制自动提取数据。

如果你想在中国购买dylos dc 1100 pro, 带pc接口仪器,请确定你购买的正确的专业版仪器。目前,在京东上海没有找到出售专 业版仪器的卖家,在淘宝上只有几个卖家。如果你真的想尽快买到我们推荐的dylos dc 1100 pro, 带pc接口 专业版仪器,但是又不想等待到货时间,可以购买价格更贵的,但是dylos dc1700仅是做了一些简单的升级,并不会改变我们检测出的空气质量检测结果。


为了把自动提取的数据传输到服务器,还需要: (278人民币) 和一个(20人民币), 清单总计:2188人民币左右。

dylos dc1100 pro
with pc interface
serial to usb cable raspberry pi

the documentation and scripts for connecting the dylos particules counter to the raspberry pi, and automatically uploading the dylos data to the world air quality project server are available freely from github: . if you have any questions, you can contact us with the subject "dylos experiment".

also, please note that when you setup your dylos particule counter outside, you need to be carefull where you locate it. ideally, it should be in a place which is not too windy, as the wind can have a significant impact on the readings (the reason is that the dylos counter is using a simple fan to get the air inflow, and the volume of air inflow per minute needs to be constant in order to have accurate readings ~ this simple fan is one of the reason why this kind of material is so affordable compared to the professional metone bam sensors).





如图所见,dylos与bam读数间的相似度非常高,但也并不总是对得上的。在这篇文章的第二部分(将在两个后,收集到足够的数据后发表),我们将提供更多有 关读书的统计分析数据。

如果你有兴趣参加这个实验,建立你自己的dylos监测站,请与我们联系。我们会为你提供所有的程序代码与设置 细节,安置你的数据库传感器,这样你就可以实时观测到你自己的读数了。


june 25th 2013

with the recent affecting singapore and now , we got many questions about why there is a difference between the data which can be read from singapore nea website () and the world air quality index project .

for instance, here is what can be read today in nea website:

may 20th 2013

shenyang city aqi data is now based on the maximum of the , and . for more infomation, please refer to the article about

february 7th 2013

由于历史原因,世界空气质量指数项目的网站一直使用的是中国环保部所指定的空气质量标准。从现在开始,所有的指示将会被沿用,并采用美国环保署的 标准。


空气质量指数范围 之前使用的中国环保局的指示 现用的美国环保署的airnow 指示 之前的中文翻译 新的中文翻译 新的日文翻译 新的韩语翻译 新的俄语翻译 颜色代码
0-50 excellent good 优秀 파랑среднее
51-100 good moderate 초록неподходящее для особо восприимчивых
101-150 lightly polluted unhealthy for sensitive groups 微污染 轻度污染軽微汚染노랑плохое
151-200 moderately polluted unhealthy 轻度污染 中度污染軽度汚染주황нездоровое
201-300 heavily polluted very unhealthy 中度污染, 重污染 中度污染中度汚染빨강очень нездоровое
301-500 severely polluted hazardous 污染严重的 重度污染重汚染갈색опасное



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february 3rd 2013
今天我们来讨论的常问问题条目是有关我昨天发表的 的。 我的朋友klaus 就防护口罩的有效性提出了质疑。他事实上是在疑惑现代口罩是否可以在时下有效地过滤所有的小的有害的pm2.5微粒物质?

实际上,这是一个非常好的问题!在北京,如果你不得不戴口罩,那么最好确保口罩真的可以过滤那些有害物质。 由于我没有答案来回答他的问题,我给新加坡totobobo口罩制造公司的francis chu 发了一封邮件,他马上给出了回答:

对于不熟悉微粒大小的读者来说,pm10 指的是小于10微米的颗粒物质,对于pm2.5来说,它指的是小于2.5微米的颗粒物质。 因此,过滤掉所有小于0.1微米的物质,意味着它可以过滤掉小于pm2.5 25倍的有害物质!所以,klaus,不用担心,最新的技术肯定是有效的!

有关颗粒大小的详细信息,可以参考维基百科网页。 如想获知更多空气过滤器如何实际测验的,或者如何比较各种口罩品牌,可以查看totobobo信息丰富的 。

  • 可直接访问totobobo公司的。

  • 可在上选择卖家。


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february 2nd 2013

本周我们从severine p收到了一个很好的相关问题。 他问了有关pm2.5与pm10相抵触的问题。 sp在邮件里问道:

我不明白为什么pm2.5 的浓度 经常比pm10 的高。
sp的问题是完全正确的:pm2.5 用定义来解释,就是比2.5微米小的颗粒,所以它们确实应该被包括在比10微米小的颗粒里面。

但是假设有关的浓度是不正确的:pm2.5的浓度可以比pm10的浓度小。然而,被修改过的值可以高一些。 举个例子,一个pm2.5的空气质量指数为50,它与每平方米15.5微克是一致的。然而,它与pm10的每立方米55微克也是一致的。

所以,即使pm2.5的每平方米15.5微克浓度全部被加进pm10的浓度里,pm10的空气质量指数依然保持比pm2.5的空气质量指数更低。 例如,本周早些时候,东城东四地区的pm10的浓度为366,空气质量指数的结果为216,可是,东城东四地区的pm2.5浓度为348,空气质量指数的结果为398.

为了双重确定我们的理解是对的,我们联系了在世界上享有声誉的空气质量专家,来自 的 博士,她回复到:
你说的这些是对的。差别是由于对于pm2.5和pm10的不同拐点 (break points), 流行病学的数据与pm2.5及pm10浓度的不同幅度 是如何关联的。 (how the data is correlated to each of the fractions)

所以,下一个问题是关于pm10的关联(中肯),尤其是在中国,大多数时候(尤其是被确认过的)都是完全正确的,这空气质量指数中pm2.5是具有显著优势的价值,因此,我们依然需要pm10的检测吗?它还是中肯的吗? 此外,当遇到从他出得到了pm10的空气质量指数比pm2.5的高的情况时呢?有关这个问题,我们再次咨询了 博士,他回复到:
现在有新的研究可以提供证据,即pm2.5比pm10更为有害。 从身体角度来说,这可以说明,更小的颗粒更有可能进入肺的深处来伤害我们。这也是世界卫生组织(who)推动所有的国家拥有pm2.5标准的一个重要原因之一。

有关问题,当我们进行pm2.5的时候,还需要有pm10浓度吗?是的,我们依然需要。在pm2.5的分数在pm10里提高的时候,对于大多数污染来自交通及燃烧城市, 经常被忽视非燃烧源就是再-悬浮尘埃(来自公路尘埃和尘暴),是形成coarser分数的一部分(从pm2.5到pm10)。如果我们突然停止检测pm10,我们就会忽视这一来源。

非常感谢sarath guttikunda博士既迅速又专业的解答。


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january 19th 2013

上海空气质量指数目前以 、 和 三个监测站的最大值为基础。

第一个监测站主要由 维护, 后两个监测站的数据由 提供,都是政府管理的监测中心。


january 11th 2013

for more information, please refer to the shanghai aqi update explanations. the following graphics show the relative pm2.5 aqi data for beijing stations on which the overall beijing aqi is based.

january 11th 2013

for more information, please refer to the shanghai aqi update explanations. the following graphics show the relative pm2.5 aqi data for chengdu stations on which the overall chengu aqi is based.

本网站采用的污染指数和颜色与epa是完全相同的。 epa的指数可以从上查到

0 - 50一级(优)空气质量令人满意,基本无空气污染各类人群可正常活动
51 -100二级(良)空气质量可接受,但某些污染物可能对极少数异常敏感人群健康有较弱影响极少数异常敏感人群应减少户外活动
300 六级(严重污染)健康人群运动耐受力降低,有明显强烈症状,提前出现某些疾病儿童、老年人和病人应停留在室内,避免体力消耗,一般人群避免户外活动


有关健康建议详见北京的richard saint cyr md医生的博客:

注意事项: 所有空气质量数据在发布时均未经验证,并且为了保证数据质量,这些数据可能随时被修改,恕不另行通知。 项目在编制此信息的内容时已经运用了所有合理的技能和谨慎,在任何情况下项目团队或其代理人将不会为由于提供此数据而直接或间接引起的伤害、合同损失、侵权及其他任何损失负责。



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