China and the U.S. are two of the world's top polluters of air [source: AFP]. Los Angeles, long thought to be one of the world's worst cities for air quality, has been surpassed by Beijing [source: Wired]. Prior to the opening of the 2008 Olympics, Beijing's air had five times the upper limit of the World Health Organization's safe level of ozone and particles emitted from diesel engines [source: IHT]. Concerns about the air quality in Beijing were so great that some athletes who were to compete outdoors in the 2008 Olympics included masks with their equipment [source: Wired]. China has been on a massive economic growth spurt for some time now, and the effects of industrialization have no doubt contributed to the lousy air quality.
Chinese citizens may take some solace in the fact that the government there seems finally to be taking steps toward more stringent air pollution standards. In the fall of 2011, an environment minister said the country will be tightening standards to prevent the haze over it cities, noting that China also will begin using PM2.5 data indicators in those standards as well [source: Watts]. PM2.5 is the designation for something called particulate matter -- basically particles in the air. The number 2.5 refers to particles that are less than 2.5 micrometers in diameter -- in air-quality speak, such particles are called "fine" and, thanks to they're small size, they're considered the most immediate health risk to citizens. (They are so small that they can lodge deeply in a person's lungs.) [source: EPA].
The PM2.5 data was a bone of contention between the Chinese government and its citizens. The government did not use PM2.5 in its national air quality index, which made for much rosier summaries of the air than the people were experiencing directly out on the streets. Citizens described the air as thoroughly awful, and with the fall 2011 announcement that standards will be more thorough perhaps there is a chance for cleaner air down the line in China [source: Watts].
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