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Tuesday, February 22, 2011
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Chinese NGO releases Air Quality Transparency Index

By Susanne Stahl

Guest post by Angel Hsu

Chinese NGO releases Air Quality Transparency Index was originally published on Angel Hsu’s website. To view the charts accompanying the post, please visit her site.

Hsu is a doctoral student at the Yale School of Forestry and Environmental Studies. Her research focuses on Chinese environmental performance measurement, governance, and policy.


The Institute of Public and Environmental Affairs (IPE) and Renmin University School of Law recently published the first version of what they’ve deemed the Air Quality Transparency Index (AQTI; available in Chinese only for now).  Building off of similar indices aimed to gauge the availability and access of environmental information, such as the Pollution Information Transparency Index (PITI), the AQTI’s aim is to compare the transparency of air quality information in 20 Chinese cities and 10 international cities, mainly from North America and Europe.

The AQTI is significant start in providing greater and much needed context for air quality data in China, which have often been criticized for being confusing and misleading at times.  Moreover, international agencies such as the World Bank has reported harrowing statistics suggesting China is home to some of the post polluted cities in the world.  While reports like these do point to the serious environmental and health hazards caused by air pollution in many Chinese cities, it is important to note that international scrutiny of China’s air quality data would not even be possible of China didn’t make the data publicly accessible in the first place.  There are potentially cities in the world with more serious air pollution than those in China, however perhaps unknown due to data and information limitations.

I’ve read over the report and the accompanying technical specifications (both are currently only available in Chinese; but I’ve attempted to quickly translate the 4-page technical document into English here*). Chinese cities selected include: Beijing, Guangzhou, Shanghai, Ningbo, Chengdu, Guiyang, Wuhan, Tianjin, Chongqing, Fuzhou, Dalian, Kunming, Nanning, Nanchang, Hohhot, Changsha, Nanjing, Zhengzhou, Lanzhou, Urumqi.  To compare to other cities internationally, the researchers selected New York, Los Angeles, London, Paris, Berlin, Vienna, Hong Kong, Moscow, Mexico City, New Delhi.

The AQTI evaluation system draws on the IPE and the Natural Resources Defense Council‘s PITI evaluation index system.  Roughly speaking, the PITI gauges 113 Chinese cities’ performance on pollution information transparency using eight metrics, which are then evaluated according to four evaluation criteria: systematic disclosure, timeliness, completeness, and user-friendliness (Table 1).

Table 1. Indicator scoring rubric for the AQTI. Source: Sabrina Orlins, NRDC/IPE.

These same four criteria were also used to gauge the transparency of information related to nine pollutant indicators:  Particulate Matter with a diameter 2.5 microns or less (PM2.5); Sulfur Dioxide (SO2); Nitrogen Dioxide (NO2); Carbon Monoxide (CO); Ozone (O3); Volatile Organic Compounds (VOCs); Lead (Pb); and “others” (Benzo[a]pyrene or B[a]P; Mercury (Hg) and Dioxin).

Table 2. Indicator weightings. Adapted from AQTI, 2011.

To determine the contribution of each indicator to the overall index, four criteria were used:
1) Degree of danger to health
2) Pollutant load
3) Developed country management status and trends
4) Domestic management status and capacity

For each of the nine pollutant indicators, gradings of high, medium and low were assigned to gauge the importance of each related to the above four factors.  Following this exercise, PM10, PM2.5, SO2, and NO2 were determined to be the most important indicators and weighted at 60 percent, with each indicator assigned 15 percent of the overall score. CO, O3, VOC comprise the second category with 30 percent, and each indicator is given 10. The last category that includes lead and other pollutants comprises 10 percent, with each indicator representing 5 percent of the overall index (Table 2).

So, how did the 20 Chinese cities do?  Table 3 shows a table of each city and how they performed with regards to transparency of information for the pollutants scored.  Notable gaps include lack of reported, available information on PM2.5, and for most cities other than Beijing, CO, O3, VOCs, Pb, and others.  Beijing, as the nation’s capital, not surprisingly, comes in first; Urumqi, the capital of Xinjiang province, comes in last.

Table 3. How Chinese cities scored for each pollutant indicator. Adapted from AQTI, 2011.

How did the Chinese cities compare to the 10 international cities found in the reference group?  Figure 1 compares the AQTI scores of the 10 reference group cities (in teal) and the 20 Chinese cities (in red).  As one can see, all Chinese cities, with the exception of Beijing to New Dehli, fall behind international counterparts.  Why is this the case?  The report provides some reasons for the discrepancies: differences in air quality laws that require provision of more comprehensive pollutant measurement; developed countries tend to set targets according to World Health Organization guidelines which require more information.  Figure 1.8 on Page 9 of the report includes a table that shows coverage of pollutants measured in major cities throughout the world. However, the Chinese government has indicated improvements in air quality measurement and monitoring in the next major policy plan – the Twelfth Five-Year Plan.  My colleague at NRDC, Alex Wang, details some of these improvements in this blog post.

Figure 1. Comparison of AQTI scores for Chinese and International cities. Adapted from AQTI, 2011.

While pointing out these air quality information gaps, one should note that the AQTI does not provide an indication of air quality; but rather its aim is to compare the availability and transparency of air quality information reported by these 20 cities in China.  To try to get a better sense of how the AQTI results stack up to actual air quality performance, I plotted the AQTI scores against the percentage of Class 1 (a score of 50 or less on China’s Air Pollution Index) air quality days that particular city achieved in 2010.  As clearly illustrated, information transparency and performance on air quality do not necessarily go hand-in-hand in China.  Page 29 of the report shows a similar chart that plots yearly-averaged PM10 concentrations against AQTI scores.  For the international cities in the reference group, at least, a positive relationship between lower annual PM10 concentrations and higher information transparency seems to exist.  This could suggest that as Chinese cities improve the transparency and availability of air quality data, the overall quality of air could improve.

Figure 2. AQTI scores versus Percentage of ‘Class I’ air quality days in 2010. Sources: AQTI, 2011 and MEP, 2011.


Special thanks to Sabrina Orlins of IPE/NRDC, Alvin Lin of NRDC, Yupu Zhao of Yale School of Forestry and Environmental Studies for their assistance in this post.


Air Quality Information Transparency Index (AQTI). January 18, 2011. Institute of Public and Environmental Affairs and Renmin University Center of Law. Available for download here: http://www.ipe.org.cn/Upload/IPE公告/AQTI-final-20110118.pdf.

Ministry of Environmental Protection (MEP). 2011. Datacenter can be accessed here: http://datacenter.mep.gov.cn/.

*Note: the translation provided in the link represents my interpretation alone and is not the official English version from IPE and RUC. It is only meant as a guide to help understand how the AQTI was determined.

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