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China's air pollution condition (PM 2.5) and its root causes

This story introduces the severity of China's air pollution in terms of PM 2.5 and discusses the main causes for it. The story also draws comparison of China and the US in terms of pollutions levels, pollutions standards and energy comsumption.


  1. Extreme pollution in Shen Yang: This is a picture of Shen Yang, this past November of 2015, when PM 2.5 concentrations hit over 1400 micrograms per cubic meter, 40 times above the healthy level dictated by the Chinese government. Shen Yang is a major city in the northeast of China with over 10 million people. It is also the city where some of my family and friends live.
  2. China's current PM 2.5 condition: China currently has a national ambient air quality quality standard of 35 micrograms per cubic meter, below which is considered a safe level. However, only 25 of its 190 major cities meet that standard, according to a recent report. The figure above shows the annual average PM 2.5 level in the 190 major cities. From the figure, you can notice that the unhealthiest cities are in the Beijing-Tianjin-Hebei area. The metropolises Shanghai, Shen Yang, Chongqing and Chengdu, with a combined population of over 50 million people, also do not fair well in the contest of cleaniness. The population-weighted mean of the entire country is 61 micrograms per cubic meter, 3 times that of the global average, and 6 times that of the healthy level recommended by the WHO. (Photo source: article in "Nature", )
  3. China's PM 2.5 levels compared with the U.S. : To understand the severity of China's PM levels, we need to draw comparisons between this Asian Giant and the U.S. and the world. The United States in 2014, in comparison, has a national average concentration of between 8 and 10 micrograms per cubic meter, one sixth that of China. Even county Kern of California, the county with the highest PM 2.5 concentration in the States (19.7 micrograms per cubic meter), is better than China's cleanest city, Haikou (25.6 micrograms per cubic meter). To make comparisons even more interesting, the PM 2.5 healthy standards are different by themselves in the two countries to begin with.
  4. China's PM 2.5 standards compared with that of the U.S. and the rest of the world: China's current air quality standard states that an annual average concentration below 35 is considered safe with the daily maximum below 75. The U.S., on the other hand, has much stricter standards, lowering the safe level to be 12 for the annual average and 35 for the daily maximum. What is considered healthy in China, a 35 in the PM 2.5 concentration, can only be considered moderate by U.S. standards, and is on the verge of being unhealthy for sensitive groups. Compared with any other major country with a PM 2.5 standard, China consistently has a weaker standard, deeming healthy what other countries consider unhealthy. In the following picture, Japan, Russia and South Korea all have more stringent standards for PM pollution.
  5. Almost no Chinese is unscathed by the bad air: In the figure above, we can see that almost everyone is the 190 major cities in China are breathing air that is over the healthy limit by WHO standards. Even by China's own safety standards, over 90 percent of the entire Chinese population are in peril. People in the Yangtze River Delta, near Shanghai, and in the Beijing-Tianjin-Hebei area, are under even more severe conditions than the national average.
  6. Imgur: The most awesome images on the Internet
    Imgur: The most awesome images on the Internet
  7. China's primary energy consumption by source,
  8. U.S. primary energy consumption by source and demand by sector
  9. Causes of China's Pollution: I believe China's high PM level has four primary sources: coal-fired electricity generation plants, coal-fired winter heating, vehicle emissions and massive infrastructure construction.
  10. Causes -- Coal-fired electricity plants: Most of China's primary energy source and electricity generation source is coal. From the figures above, China has a skewed energy supply source of 66 percent coal, with most of it going into the electricity generation, residential heating and industrial sectors. The combination of coal as a naturally polluted source for electricity generation and a lack of particulate matter control technology produces large masses of dirty particulate matter that roams the country. The U.S., on the other hand, only uses 20 percent of its primary energy source as coal and uses less than 50 percent coal for electric power generation. This fact combined with state of the art pollution control technology leads to cleaner power plants in the U.S. that don't emit too much PM 2.5. The great number of coal-fired power plants in the Hebei and Henan provinces that surround Beijing is a key reason for the extremely high PM levels in the nation's capital.
  11. Causes -- Coal-fired winter heating: The majority of winter heating in China comes from burning coal. Many Chinese cities burn coal to heat water, and run hot water through residential and commercial buildings to disperse heat to the users. This is especially bad for air pollution since these heating plants, unlike power plants, reside within the city limits and are in very close proximity with the large number of people living within the cities. Winter heating is also the reason why the most severe air pollution events in China occur during the winter instead of the summer. It is also the reason why northern China generally has worse conditions compared with the south as northern China requires more heating during the winter and throughout the year.
  12. Causes -- Vehicle emissions: China is growing exponentially in vehicles owned per capita. As can be seen in the picture above, the number of automobiles in China doubled in merely 5 years from 2009 to 2014. These vehicles are driven mostly in the major cities by China's east coast than in the rural interior. Chinese vehicles most likely have less stringent emission standards than their American counterparts. The result is massive emissions, particularly PM 2.5 by these vehicles.
  13. Causes -- Infrastructure construction: As a developing country, China is still building its infrastructure at a tremendous rate. China is expanding its subway system nationally to accommodate more public transportation underground. Currently, the country has subway systems in 24 major cities. It is looking to double the subway system size within these cities as well as initiate subway transportation in 17 additional cities by 2020. China is also expanding its high-speed rail system on a national scale, which allows trains to reach over 250 kilometers per hour. The great amount of construction within China's major cities generates a great amount of construction dust and contributes largely to the suspended particulate matter in the air.
  14. China still has a long way to go: To understand China's air pollution, we also need to take into consideration that China is still a developing country. The country is in a phase where its economic development has caused severe environmental repercussions. The U.S. also had its air pollution problems in the 1970's and only improved its air quality through consistent prevention efforts during the following decades. The hope is that with concrete efforts, China will achieve better air quality in the not-so-distant future, by which time millions of Chinese people just like me will be more willing to go back home.