Airborne particulate size chart Logarithmic scale shows particle diameter in microns |
International Business Times has a story about air pollution in China. Seems that draconian censorship cannot make gray skies blue.
The article talks about PM2.5, which it refers to as particles less than 2.5 mm in diameter. In my book 'mm' means millimeters. 2.5 mm would be a tenth of an inch in diameter. That doesn't seem right. I suppose the author thought that mm was a suitable abbreviation for micrometers. Hence my preference for the term 'microns'.
Note that the scale is logrithmic and goes from 1,000 microns (which is 1 millimeter) on the right down to one-ten-thousandth of a micron (or 1 angstrom) on the left. One millimeter is about the thickness of a dime. One angstrom is about the diameter of a water molecule, hence the 'Gaseous Contaminates' cloud in the lower left corner.
One commentor noted that ". . . none of China's worst polluted cities is even in the world top ten", which leads us to:
World's most polluted cities |
Delhi is in India, but Patna? Khorambad? Never heard of them. Turns our the top ten cities in the above graph are all in India, Pakistan and Iran. Just goes to show that pollution has no respect for politics. Democracies can be just as unhealthy as totalitarian dictatorships.
Update November 2020 replaced missing chart.
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