Editor’s Note: Over the last few weeks, China has come under scrutiny for the increasingly dangerous air quality of many of its cities. International criticism has particularly been directed at Beijing—the New York Times recently published an article which reported that officials were spending thousands of dollars on premium air purifying units, as well as disclosing that China had (according to a leaked wikileaks transcript) requested that the US Embassy quit posting its Air Quality Index, or block the site to Chinese viewers. Many Chinese media sources have adopted an uncharacteristically critical outlook on this issue as well. The following article, which first appeared in the Beijing Times, introduces readers to the basic science behind PM10 and PM2.5, explains how China currently measures (and will “eventually” measure) air quality, and how some individuals, tired of waiting for the government, have begun measuring PM2.5 in Beijing by themselves.

On November 1st, the Ministry of Environmental Protection announced the implementation of the "Ambient Air Quality PM10 and PM2.5 Weight Measurement Law". This is the first time that China has used the PM2.5 specifications for measuring particulate matter. Yet, for the time being, none of this really matters because the Ministry of Environmental Protection’s “Ambient Air Quality Standards” (AAQS) has still not been revised to include PM2.5 as a mandatory monitoring indicator.

Air Pollution 101

PM is an abbreviation for "particulate matter". PM10 refers to matter suspended in the air whose diameter is less than or equal to 10 micron particles (such as dust). Particles this size can be inhaled and accumulate in the body's respiratory system, although they can be rejected by the body by blowing your nose, coughing or sneezing, or mostly avoided by wearing a facemask. In comparison, PM2.5 refers to matter suspended in the air whose diameter is less than or equal to 2.5 micron particles. PM2.5 comes from things like factories and engines, and enters the bloodstream when inhaled. Particles this size pose a much greater threat to human health, as they are so small that they can penetrate deeply into the lungs, entering the bloodstream when inhaled, where they will remain indefinitely. Worse yet, these PM2.5 particles, compared to thicker particles stay, in the atmosphere for a longer period of time, and can be spread further. PM2.5 greatly affects both the atmospheric environment as well as human health, and is principally responsible for “grey haze” (smog) and black lungs.

Currently, Japan, the US, India and the EU have set a “national standard” for PM 2.5 and carried out mandatory measures to limit its spread. Under the 1996 edition of China's AAQS, a control standard for PM10 was listed; PM2.5 was not.

China’s New (Empty) Policy

Under the new "Ambient Air Quality PM10 and PM2.5 Weight Measurement Law", the phrase "airborne dust" has been changed to "inhalable particulate matter" (PM10). The law also requires that the weight of matter in ambient air be measured in terms of both PM2.5 and PM10. However, because the current AAQS has not yet been revised, PM2.5 has still not been added to the mandatory limitations list, so any measured PM2.5 data will be used for (internal) reference value only.

Recently, Zhao Hualin, head of the Pollution Control Office of the Ministry of Environmental Protection told the media: "We will revise and improve the AAQS as soon as possible, so that it includes a PM2.5 evaluation index. Also, according to reports, the Ministry of Environmental Protection recently demanded that "Environmental Protection Model Cities" spearhead PM2.5 monitoring.

Why hasn't PM 2.5 monitoring been implemented yet?

Beginning on October 30th, Beijing experienced three straight days of “heavy fog". According to the Municipal Environmental Protection Bureau published Air Quality Index, these days were listed as "Slight Pollution". In contrast to the official line, Weibo users took to posting the US Embassy's Air Quality Index (AQI), which reported that Beijing's air pollution was continually 300+ (hazardous). The disparity between China's official report and the US embassy's AQI can be explained by China not using PM2.5 monitoring. In a city setting, PM2.5 mainly comes from coal-fired power generation, industrial production and vehicle exhaust emissions. In many parts of China, especially in North China, PM2.5 accounts for more than half the weight of the suspended particulate matter in the air.

Experts at the Ministry of Environmental Protection have indicated that PM2.5 will be monitored in the future. So why hasn't PM 2.5 monitoring been implemented yet? It’s not that there aren't any problems with China's current technology… it’s just that "the opportune moment has not yet arrived". The official explanation is as follows: China's current PM10 concentration level is still quite high, and the problem has not yet been solved. With the PM2.5 pollution even more serious, if China were to formulate and implement AAQS for PM2.5 under these circumstances, the greatly expanded scope of the problem would make it very difficult to deal with.

At present, Beijing, Shanghai and other cities have already launched their own PM 2.5 monitoring programmes. Data shows that Beijing has had more than 40 PM2.5 monitoring sites set up since 2000, but the results of the monitoring sites have never been published.

Chinese environmentalists do their own PM2.5 monitoring

Compared to the government, individual environmentalists are very eager to publicly monitor PM2.5. In October, environmental NGO Darwin Naturalist Society began organising volunteers to monitor PM2.5 in Beijing and publish the results on their website (http://www.bjep.org.cn/). On October 22nd, real estate entrepreneur Pan Shiyi took to Weibo, posting an iPad screenshot that showed the PM 2.5 level for the embassy area by East Third Ring Road (near Liangmaqiao). It was rated at 439, or “Poisonous”. Within two days, the screenshot was forwarded nearly 5,000 times, in the process introducing many new netizens to the US Embassy's AQI website (http://beijing.usembassy-china.org.cn/070109air.html). But this information also has its limitations. The US Embassy "cautiously" explains on its website that the entire city's air quality cannot be accurately measured through the data from a single air quality monitoring station.
 

Source: jinghua.cn
 

Related links
China Preparing to Monitor PM2.5 Particulate Matter in the Air
Beijing’s Air Quality on Oct. 9th Hits Record Low
How to Breathe Easier in China’s Most Polluted Cities

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Keywords: Chinese air pollution PM2.5 and PM10 China Beijing hazardous air quality China ministry of environmental protection