Secrets of Cloud Formation, Revealed in the Amazon

Adrianne Appel, reporting for NOVA Next:

There is so much particulate matter in the air in heavily developed regions like North America and Europe—mostly from pollutants—that scientists are unable to easily study which particles impact cloud formation and how. The “cleanest” atmosphere in rural North America, for example, has 2,000 or more particles per cubic centimeter; most are from pollution. Those numbers soar near cities, where densities can be as high as 10,000 to 100,000 particles per cubic centimeter. “There is too much noise in the atmosphere,” Martin says.

There are a few places where particulate signals are quieter.

One guess where one of those is.

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