Archive for November, 2010

translation of intro pages to china’s new real-time air quality reporting site

Friday, November 26th, 2010

Earlier today, I posted the fantastic news about the beginning of real-time air quality reporting in Chinese cities. Because the site is currently in Chinese only, I’ve quickly translated the first few splash pages here:

RT report 1“Enthusiastic congratulations for the successful launch of the air quality reporting system for key cities!”

RT report 2“Introduction to the China National Environmental Monitoring Center

The China National Environmental Monitoring Center is a government-affiliated supporting research institution (事业单位) directly administered by the Ministry of Environmental Protection. It includes the national environmental monitoring technology center, network center, data center, quality center, and training center. The primary responsibilities are national environmental monitoring and environmental monitoring technology development, in order to provide monitoring information, reports, and technical support to guide national environmental management and policy.”

RT report 3“Introduction to the Reporting System

The real-time reporting system for air quality in key cities automatically reports measured ambient data for sulfur dioxide, nitrogen dioxide, and inhalable particles. Hourly average data are presented for both individual monitors and entire cities. Data for individual monitors represent the average over the previous complete hour; for example, the data for 4pm represent the average value from 3pm to 4pm. Data for a city represent the arithmetic average of all stations in that city.

The data in the system are updated once per hour. Because the data transfer requires some time, there is currently a reporting lag of half an hour. For example, the data for 3pm will be reported at 3:30pm. When the monitoring equipment is undergoing calibration or encounters some communication or power error, there may be no data for that corresponding station.”

RT report 4“Introduction to the Reporting System

In accordance with the technical standard requirements of air quality monitoring, the air quality automatic monitoring data must be audited before it can be considered as part of an air quality assessment. However, in order to fulfill the public’s right to know in a timely manner, this system automatically reports the real-time data before they have been audited.

The source of data in this system is national-level ambient air quality automatic monitoring stations, not including local-level automatic monitoring stations.”

RT report 5“The relationship between real-time reported data and daily reported data

– The real-time reporting system for air quality in key cities reports the hourly average concentrations of three types of pollutants – SO2, NO2, and PM10 – for the entire city and at each monitoring station.

– The daily air quality report that has been in place since the year 2000 reports the 24-hour average air quality for key cities. In order to fulfill the need of afternoon air quality reporting by the media, the calculation for the daily report covers data from noon on the previous day to noon on the current day. After the average daily concentrations of each pollutant are calculated, they are converted to an Air Pollution Index (API), which can be easily understood by the public.

– Because the API is based on a 24-hour average of each pollutant, China, like many countries, currently does not provide an hourly API. Therefore, the real-time reporting system will only report the hourly concentration of each pollutant. The 24-hour averages will still be used for the daily API calculation.”

huge news – china begins hourly air quality reporting

Friday, November 26th, 2010

Wow, HUGE news today regarding air quality reporting in China: China’s National Environmental Monitoring Center has begun reporting hourly air quality data at over 2,000 individual monitoring stations in 113 cities in China. This represents a major development towards information transparency in China, and a key step towards providing residents here with the type of real-time air quality data they need to make healthy decisions regarding personal exposure. The release of this data will also pave the way for vast amounts of future research into the nature of air pollution in China.

In addition to providing data, the site is an extremely valuable resource for general information about China’s air quality, including air quality standards, definition of Air Pollution Index, impacts from air pollutants, main sources, etc. In many ways, the site is a like a very primitive version of the US EPA’s air quality public outreach site, After what has seemed like a frustrating year for air quality in China, this is a wonderful development for which China deserves great credit.

The main address for the site is, with the actual data accessible at The site is currently exclusively in Chinese, and is developed in Silverlight, which is apparently a Microsoft version of Flash. (I had to download it from Microsoft’s website before I could view the site.) Because of the way the site is structured, it seems impossible to link to individual pages or copy/download data. This is an annoying and frustrating flaw in my opinion, but I’ll take what I can get for now.

I’m sure I will have many, many more posts about this new site and the treasure trove of data that’s available there. For now, though, let me just show a couple of examples of the type of information available:

This chart shows hourly concentrations of SO2, NO2, and PM10 from 7am this morning to noon at the Dongsi monitoring station in downtown Beijing:

dongsi real-time
This graph shows the hourly PM10 concentrations at that same individual station over the last 48 hours. The red line represents China’s daily air quality standard. The green line shows the previous day’s average.

pm10 real-time
Again, much more analysis to come, but for now my lunch break’s over and I need to get back to my day job. I’m happy to be bringing this positive report for a change, and look forward to providing more analysis and translation in the near future. In the comments section below, please feel free to ask specific questions about this new service and I’ll do my best to answer them.

for readers in shanghai – new indoor air quality testing company open for business

Friday, November 26th, 2010

To any readers in Shanghai:

A good friend of mine recently launched a new company called PureLiving: Indoor Environmental Solutions:


PureLiving China is a Shanghai-based indoor environmental health and safety consulting firm focused on advising our clients on air and water quality, mold, and lead exposure issues. Within our full range of services from testing to problem resolution, our focus is on assessment, root cause analysis, and independent recommendations. We are not tied to any particular brand or type of remediation strategy, but facilitate a wide network of specialists and supervise the work on our clients’ behalf.

Readers often e-mail me with specific questions about their own personal exposure to indoor air pollution, and how to mitigate it. If you are in Shanghai and would like a professional evaluation based on international standards and someone to help solve any problems found, I strongly recommend you reach out to PureLiving China. Their website is also a good source of general information on the risks associated with indoor environmental pollution in China.

More info available at

Disclosure: PureLiving’s founder, Louie Cheng, is a close friend of mine. I have advised him from time to time on air quality-related research questions (e.g. international standards comparison), but I am not officially involved in the company in any way, and have no financial conflict of interest.

“crazy bad” air quality in beijing

Wednesday, November 24th, 2010

crazy bad aqi chartI’ve taken the liberty of updating the US EPA’s AQI colors chart

A few days ago, the US embassy’s BeijingAir Twitter feed, which automatically reports Beijing’s hourly air quality, made headlines across the web by announcing that the air quality was “crazy bad.” Although the wording was quickly revised to the more politically-palatable “beyond index,” the impact was immediate. “Crazy bad” air was all the buzz of the blogosphere and at social events over the weekend; I have a feeling “crazy bad” would make it onto Beijing’s Word of the Year list, if there were such a thing. MyHealthBeijing‘s Dr. Richard St. Cyr even suggested “Crazy Bad” T-shirts.

In this post, I’ll look a little closer at the data behind the Crazy Bad incident to see what we can learn. The graph below shows hourly and daily data from the BeijingAir Twitter feed along with official air quality data from the Ministry of Environmental Protection (available here, Chinese only). For clarity, I show all data in terms of particulate matter concentration, not standardized index. (I’ve converted MEP’s reported API numbers to PM concentration; for background on the difference and methodology, see this post.) Note that MEP’s data is reported for a 24-hour period from noon to noon, which is why the daily data changes at noon each day. The break in the red corresponds to the BeijingAir Twitter feed not reporting any data for a couple of days after the Crazy Bad incident.

crazy bad

This graph reveals some really fascinating info:

1) The Crazy Bad spike on Thursday and Friday last week was both preceded and followed by gorgeous, wonderfully clean weekend days. On 11/15, the air quality was, by all accounts, “good.” By 11/18, though, the air pollution had steadily risen to what the US calls “hazardous“/”crazy bad,” and China calls “heavily polluted” (“重污染”). After the steep rise, the air quality improved just as dramatically; MEP’s reported PM10 numbers dropped 297 points – from 334 to 37 – from 11/21 to 11/22 alone. This demonstrates just how quickly the air quality can change in Beijing – both for better and for worse.

Why did it change so quickly? The start of the heating season on 11/15? Possibly, although that wouldn’t explain the sudden drop beginning 11/20. To be honest, the answer is probably less dramatic: weather. Most day-to-day pollution changes in Beijing are caused by changes in temperature and wind patterns. If there are a few days of static air, or light winds blowing from the southeast and trapping pollution against the mountains to the north and the west, the pollution builds up very quickly. I should find the time to post separately about this.

2) MEP’s air quality data tracked the embassy’s with reasonable consistency. This is actually encouraging; we should be grateful at least for some degree of accuracy and transparency with official data. There are some differences, but we shouldn’t expect them to track exactly. This is because the MEP data is an average of multiple sites across the city, while the embassy data is just a single point. Plus, they are measuring slightly different things.

In the past, we have seen situations where rapid and very short-term pollution spikes highlighted by the BeijingAir hourly readings were not reflected in daily MEP averages, but that doesn’t appear to have happened here.

(As I point this out, though, I should also note that I do not intend to make excuses for or to justify China’s current reporting mechanism. For the record, I would like to see at least three immediate changes to China’s air quality reporting: hourly release of data, more representative descriptions of health impacts, and some sort of real-time alert system for at-risk populations to avoid exposure.)

Lastly, a few data highlights for the numbers geeks out there (background on international standards here):

US EPA daily ambient air quality standard for PM2.5: 35 ug/m^3
Peak PM2.5 concentration reported by BeijingAir, 11/19: 557 ug/m^3

WHO recommended daily limit for PM10 exposure: 50 ug/m^3
China daily ambient air quality standard for PM10: 150 ug/m^3
Peak PM10 concentration reported by MEP, 11/19: 430 ug/m^3