CIIC:Today's featured article/May25, 2012
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Revision as of 06:02, 25 May 2012 by imported>Ciic
File:The smog in Beijing.JPEG
The smog in Beijing
Particulate matter, or PM, is the term for particles found in the air, including dust, dirt, soot, smoke, and liquid droplets. PM2.5 particles are air pollutants with a diameter of 2.5 micrometers or less, small enough to invade even the smallest airways. (More...)
