"The measurements of CFC-11 in the stratosphere were first described in 1975 by two research groups in Boulder, Colorado, and have been similarly observed innumerable times since. The uniform mixing of CF4 versus altitude was reported from balloons around 1980 and many times since, and from an infrared instrument aboard the space shuttle Challenger (which exploded in 1986) in 1985. My own research group has measured CFC-11 in hundreds of air canisters filled while flying in the NASA DC-8. We once did a descent directly over the North Pole and found uniform mixing in the lower atmosphere, and slightly less CFC-11 in the stratosphere.

2 Comments

1. 1. dan6807 06:36 PM 1/10/09

   What was the effect of the SR71 Blackbird using freon to cool it's exhaust so heat seeking missles would be spoofed?

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2. 2. chemguy 04:42 AM 8/30/09

   Is this the same with halogens? As they are a different chemical makeup and are also heavier than air or is this just for CFCs.

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