Archive for the ‘air pollution’ Category

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beijing’s good air quality streak ends at 43

Wednesday, February 9th, 2011

Beijing’s longest streak of consecutive Blue Sky Days ended last Thursday after an unprecedented 43 days. It was a wonderful start to 2011: the cleanest January since 1998 and average air quality on par with that of the the Olympic and Paralympic Games period.

In my last post, I wondered why the Beijing EPB hadn’t claimed more vociferous credit. A few days later, they did just that. Du Shaozhong, a Deputy Director at the Beijing EPB, gave an “ebullient” interview to Jonathan Watts of the Guardian. (I’m honored that Watts also quoted this blog towards the end of the article.) Director Du described the comprehensive policies that Beijing has adopted to control air pollution, including retrofitting coal-fired power plants, switching home heating from coal to natural gas, implementing progressively stricter tailpipe emission standards, and scrapping older, high-emitting vehicles. He claimed that these efforts have resulted in a “positive, long-term story” of Beijing’s air quality since 1998. The improvements are particularly remarkable given the growth that Beijing has experienced during that time (e.g., the vehicle population increased from 1 million to 4.8 million from 1998 to 2010).

Overall, it’s a strong interview and article full of good information. But it’s also interesting to note what Director Du did not mention:

1) Why was January’s air quality so unusually and dramatically good? Watts writes, “[Director Du] acknowledged that the air quality over the past month had benefited from meteorological conditions – strong winds and cold fronts – but said the improvement was far from a one-off.” The problem here is that the air quality in January was so unexpectedly good that the explanation that it was simply – or mainly – the result of Beijing’s long-term pollution control efforts is unbelievable. Surely the Beijing EPB has some estimate of the contribution of favorable weather / wind to last month’s good air quality, especially considering the Beijing EPB has blamed the weather in the past for poor air quality? If January’s good air quality was “far from a one-off,” does this mean we can expect this much improved air quality to continue? (If it doesn’t, then I will be very curious to see what explanation is offered (if any) when the air pollution levels go back up to more expected levels for this time of year.)

2) It’s true that 2011’s air quality has been very good compared to 1998. But isn’t it disingenuous to claim a consistent trend given the fact that Beijing’s average air quality has stagnated since 2008? Existing control programs have seemingly been effective in maintaining the current air pollution levels in the face of continued rapid growth. Barring continued favorable weather, is there strong reason to expect that the remainder of 2011 will be better than 2009 and 2010?

Posted in air pollution, beijing, blue sky days | No Comments »

beijing enjoys first completely blue sky month since 1998

Monday, January 31st, 2011

Beijing’s incredible streak of consecutive Blue Sky Days continues, standing now at 40 days. (Past coverage here and here.) As I noted in my last post, what we are experiencing is not merely some minor or subtle improvement. Beijing’s air pollution levels over the past month have been less than half of what they usually are this time of year. This is remarkable.

The Beijing Environmental Protection Bureau weighed in today in their monthly air quality assessment:

1月份，我市空气质量天天达标，其中一级18天，二级13天，比去年同期多6天，距全年274天（75%）的目标还差243天。全月空气质量天天达标，是我市自1998年以来第一次。

1月份空气质量天天达标，充分说明我市多年来防治大气污染尤其是治理冬季燃煤污染取得了明显成效。

市环保监测中心专家指出，春节期间开车出行和燃放烟花爆竹等也会影响到空气质量。希望大家注意合理用车，有节制地燃放烟花爆竹，尽可能减少这些活动对大气环境的影响。

Rough translation (emphasis mine):

In January, Beijing’s air quality met the standard every day. There were 18 Grade I days and 13 Grade II days, an increase of 6 days more than the same period last year. There are 243 days remaining before Beijing achieves its yearly target of 274 (75%) days meeting the ambient air quality standard. This month is the first complete month since 1998 in which every day in Beijing has met the air quality standard.

That every day in January met the air quality standard is a strong testament to the clear results obtained by many years of pollution prevention and control work, especially control of pollution in winter from burning coal.

Experts from the Beijing Environmental Monitoring Center note that car operation and fireworks during the Spring Festival time will affect air quality. Everyone should pay attention to use vehicles reasonably and set off fireworks in a controlled way, so as to reduce the impact of these activities on air quality.

The summary is rather understated given how dramatically improved the air quality was this month. My guess is that the Beijing EPB is as surprised as the rest of us at how terrific the air quality has been recently, and are reluctant to claim too much credit before further analysis is done. While it’s true that we are certainly seeing some fruits of the variety of emission control programs implemented over the past decade, I think that a bigger factor recently has been consistent weather patterns favorable to pollutant dispersion as opposed to major changes in source emissions.

This graph shows my estimations of average PM10 concentration in Beijing in January, 2001-2011. This year is clearly a (very welcome and very dramatic) anomaly:

january pm10

Posted in air pollution, beijing, blue sky days | 1 Comment »

beijing breaks record for longest streak of consecutive blue sky days – best air quality in years

Thursday, January 27th, 2011

Great news! Today is Beijing’s 36th consecutive Blue Sky Day, a day whose Air Pollution Index (API) is 100 or below, indicating “excellent” or “good” air quality. As far as I can tell, this is the longest consecutive streak of Blue Sky Days in Beijing for at least ten years. Previously, there were only three streaks of 30 days or longer, one in 2006 and two during the Olympics.

Although we have seen gaming of the Blue Sky Day metric in the past, in this case both the data and public observation support dramatically cleaner air quality over January 2011 than in months and years past.

On the data side, for the 36-day period December 23, 2010 to January 27, 2011, I calculated an average particulate matter concentration of around 64 ug/m3 in Beijing. (API to PM10 concentration methodology here.) While this is still well above the WHO’s recommended annual limit of 20 ug/m3, this pollution level is less than half of that over the same period in 2009-2010, and is actually on par with the pollution levels during the Olympic (57 ug/m3) and Paralympic (71 ug/m3) periods, which were widely regarded as successful.

Looking at the data another way, an astonishing 18 of the past 36 days have been Grade I “excellent” air quality days in Beijing, which means the API is 50 or below. In 2001, Beijing only had 12 Grade I air quality days the entire year.

From a public observation perspective, I offer up for evidence the conversation I mentioned in my last post which made me start thinking about the streak, this e-mail I received two days ago from another friend:

I’ve been meaning to ask but since pretty much Christmas Eve I feel like has been the best stretch of air quality since I landed here…even better than the Olympics (which I caught the tail end of). My general air quality test is how well I can see the mountains from Tsinghua or Andingmen bridge. Rarely has there been a miss. I must have clearly seen stars all but a handful of nights and I can’t think of a day that’s looked polluted from start to finish. Are my eyes merely deceiving? Is the wind just being very helpful? Or has there actually been a drop locally?

and finally, the Beijing Air feature from the Asia Society, which features daily pictures, monthly averages, and weekly comparisons of Beijing’s air quality with that of New York. Here’s the past week comparison between Beijing (top row) and New York (bottom row):

asia society jan 11 1
They note, “This week has been by far the cleanest in terms of both blue-ness and air quality stable performance. Even New York looked less impressive.”

So why has the air quality been so uncharacteristically good recently? Unfortunately, I have no data-backed theories, although I would guess it’s a combination of existing pollution control programs and standards beginning to bear fruit, economic slowdown prior to the Chinese New Year holiday, and really favorable weather patterns that have prevented any pollution from building up. (Perhaps the lack of pollution build-up is also related to similar weather patterns that have prevented any measurable precipitation in Beijing since October 23rd.)  Regardless, it’s a great air quality start to 2011. Let’s see how much longer the streak can go.

Posted in air pollution, api, beijing, blue sky days | 5 Comments »

how long can beijing’s good air quality streak last?

Sunday, January 16th, 2011

Over the past few weeks in Beijing, the air quality has seemed uncharacteristically good. In fact, Beijing has had 25 consecutive Blue Sky Days – days for which the Air Pollution Index has been at 100 or below, representing “good” or “excellent” air quality. This morning a friend remarked that she couldn’t remember any other time when the air quality has been this good for so long continuously. I decided to investigate her claim.

Here’s what I found. Going back to 2001, I only found 6 streaks of 25 or more consecutive Blue Sky Days. They were as follows:

6/24/06 – 7/28/06 (35 days)
7/31/06 – 8/24/06 (25 days)
1/21/08 – 2/18/08 (29 days)
7/28/08 – 8/28/08 (32 days)
8/30/08 – 9/29/08 (31 days)
8/19/10 – 9/14/10 (27 days)

The two streaks in the summer of 2008 were clearly linked to the temporary pollution reduction policies put in place for the Olympics and Paralympics. I’m not sure what caused the other streaks, especially the excellent summer of 2006.

The current streak began on 12/23/10. Let’s see how long it can go! Track it yourself here at the MEP datacenter.

Posted in air pollution, api, beijing, blue sky days | 4 Comments »

summary of beijing’s 2010 air quality

Friday, January 14th, 2011

Happy New Year! For each of the past two years around this time (link to 2008, link to 2009), I’ve posted a summary of the previous year’s air quality in Beijing. This post contains some data and notes on 2010.

My data source, as always, is the datacenter of the Ministry of Environmental Protection, which archives historical Beijing air quality data here. (Note that I’m using the daily averages, not the recently released hourly data.) All I’m doing is copying the data into Excel, then parsing it and doing some conversions to look for patterns. The most important conversion is converting Air Pollution Index (API) to ambient particulate matter (PM) concentration, using the equations described here. This is important for two reasons. First, the conversion allows for averaging, which should not be done with API data directly. Second, ambient PM concentration is a much better indicator of the health impact of air pollution in Beijing, allowing for direct comparison to international air quality standards and existing health effect studies.

Now on to the data. The datacenter reports 363 data points for 2010 (3/15 and 5/21 are missing). Assuming those two days were Blue Sky Days yields a Blue Sky Day count of 286 and a calculated average PM10 concentration of 122 ug/m3. The Blue Sky Day count of 286 has been confirmed by the Beijing EPB, but the PM10 concentration value probably won’t be released for another few months.

As a reminder, Blue Sky Days are days for which the API is at or below 100, which China deems “excellent” or “good” air quality. Cities count the annual number of Blue Sky Days as an easily-understood measure of air quality progress, although the metric has been gamed in the past and is actually scientifically meaningless.

This figure shows trends of Beijing’s Blue Sky Days and PM10 concentration since 2000:

beijing air quality trends 00-10
The Bad News: Beijing’s air pollution levels, as represented by ambient particulate matter concentration, have remained flat for the past three years, actually getting slightly worse from 2009 to 2010. This is consistent with results reported in mid-2010. Beijing’s air quality still does not meet China’s own air quality standard, and is six times worse than the recommended particulate matter target set by the WHO.

The Good News: Beijing’s 286 Blue Sky Days in 2010 far exceeded its target (266), and miraculously managed to beat last year’s total by just one day. In addition, there was a slight increase in the number of Grade I (”excellent”) air quality days as compared with 2009 (as shown in the above graph in light blue). This is dramatic turn-around from the way things looked in the first half of the year. Given that over 700,000 vehicles were sold in Beijing in 2010, I suppose the fact that the pollution didn’t get even worse can be viewed in some respects as a success.

Beijing’s Environmental Protection Bureau really struggled to call 2010 a success. On December 31st, they released a short note stating, “今年我市空气质量二级和好于二级的天数累计达到286天，占78.4%，比去年多1天，实现了空气质量连续12年持续改善,” meaning, “This year, the number of days in our city meeting the Grade II or better air quality standard totaled 286, representing 78.4% of all days, one more than last year. This has realized 12 consecutive years of air quality improvement.” The last statement is highly dubious, especially given my preliminary conclusion that the average PM10 concentration was higher in 2010 than 2009. It will be interesting to see how and if the EPB’s statements change when the PM numbers are released in the environmental annual report later this year.

Related posts:
Summary of Beijing’s 2009 air quality
Summary of Beijing’s 2008 air quality

Posted in air pollution, api, beijing, blue sky days | 2 Comments »

location of hourly air quality monitors in Beijing

Wednesday, December 1st, 2010

Last week, the China National Environmental Monitoring Center (CNEMC) began hourly air quality reporting in 113 cities in China. (Previous posts here and here.) Data for individual monitoring stations are reported, although there are only 12 monitoring stations listed for Beijing. This is in contrast to the Beijing Environmental Protection Bureau, which lists 28 stations. According to my understanding, the CNEMC data that are reported are from monitoring stations part of a national network, as opposed to stations locally set up and administered by the Beijing EPB.

Of the 12 stations reported by CNEMC, 8 are in the city itself, 2 are in Changping, 1 is in Huairou, and 1 is in Shunyi. The maps on the CNEMC reporting website are terrible, and extremely difficult to navigate, but I was able to zoom in this far, which shows the 8 locations in Beijing City. I’ve highlighted the two stations closest to the US Embassy:

monitor locs
You can mouse-over the station to get that hour’s reading. Detailed comparisons of CNEMC to US Embassy results in a separate post to come, but just for one quick result: the CNEMC Agricultural Exhibition Center (农展馆) station is currently reading 285 ug/m^3 PM10. The US Embassy is reporting 257 ug/m^3 PM2.5. Because PM2.5 is one component of PM10, we should expect the Embassy’s numbers to be below those reported by CNEMC, so I’d say that’s a pretty consistent result. Do I dare say “good enough for government work?”

Posted in air pollution, beijing | No Comments »

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.”

Posted in air pollution, api, beijing | No Comments »

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, www.airnow.gov. 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 http://58.68.130.147/air/, with the actual data accessible at http://58.68.130.147/air/air/airtestpage.html. 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.

Posted in air pollution, api | 4 Comments »

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:

PL

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 www.purelivingchina.com.

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.

Posted in air pollution, indoor air quality, solutions | 1 Comment »

“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

Posted in air pollution, api, beijing | 12 Comments »

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