inFact with Brian Dunning inFact with Brian Dunning



Some people believe that airplane contrails are really the government spraying us with poison. Could this be true?

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There are at least three possibilities: contrails are the normal and expected result of fuel-burning planes flying at high altitude; all trails left in the sky by planes must be the result of the covert spraying of chemicals; or some contrails are natural, and some are chemtrails.

The first one we know for sure. When a hydrocarbon fuel burns in air, water is the largest byproduct by mass. At low pressures at altitudes higher than 25,000 feet and temperatures less than -40 degrees, water vapor always condenses into cloud; or anytime the addition of this small amount pushes the humidity past the saturation point. So in any given set of atmospheric conditions, all planes will either produce a condensation trail or not.

But what if the government wants to spray chemicals into the atmosphere, according to the popular urban legend? Is spraying from airliner altitude an effective way to do it? There are good science-based reasons why this wouldn't work. Those head winds and tail winds the pilot tells you about over the intercom are the jet streams, from 25,000 feet on up to about 60,000 feet, which includes the full range of airliner flight levels.

If the idea is to drug the population, chemtrails wouldn't work; because anything sprayed into the jet stream is going to get blown safely out to sea where it will be diluted to undetectable levels and eventually rain into the ocean.

If the idea is to spray reflective matter into the atmosphere to combat global warming, it wouldn't work for the same reason, unless it could be sprayed far higher than airliners can reach, well into the stratosphere.

Like all conspiracy theories, chemtrails require us to accept the existence of a coverup of mammoth proportions. In this case, virtually every aircraft maintenance worker at every airport in the world needs to be either part of the conspiracy, or living under a threat from Men in Black, with not a single whistle blower or deathbed confession in decades. Thousands of people discuss chemtrails freely on the Internet, so it seems we can safely eliminate the possibility that the government suppresses it. And with no suppression, you'd think everyone in the airline industry would hear about it pretty quickly. But the only outrage seems to exist only on Internet forums, among disconnected outsiders.

There are just too many reasons this particular conspiracy theory is both scientifically unworkable and sociologically implausible.

— Brian Dunning

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References & Further Reading

Anonymous. "An Airline Manager's Statement." Aerosol Crimes & Cover Up. C.E. Carnicom, 22 May 2000. Web. 11 Nov. 2009. <>

Anonymous. "A Mechanics Statement." Aerosol Crimes & Cover Up. C.E. Carnicom, 19 May 2000. Web. 11 Nov. 2009. <>

Bruce Conway. "The Chemtrail Smoking Gun - Proof of Global Geoengineering Projects." Lightwatcher. Illumina Publishing, 20 Jun. 2003. Web. 22 Nov. 2009. <>

Hope, Ray. America Sold Out. Longwood, FL: Xulon Press, 2003. 145-152.

Ludlum, David M. National Audubon Society Field Guide to North American Weather. New York: Alfred A. Knopf, Inc., 1991. 24-26.

U.S. Air Force. "Contrails Facts." Official website of the U.S. Airforce. U.S. Air Force, 13 Oct. 2005. Web. 5 Nov. 2009. <>

United States Environmental Protetion Agency. "Aircraft Contrails Factsheet (EPA430-F-00-005)." United States Environmental Protetion Agency. 1 Sep. 2000, EPA430-F-00-005.


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