Removal of chlorofluorocarbons from the troposphere

Summary form only given. It was suggested in 1989 that extremely powerful lasers might be used to break up tropospheric CFC's (chlorofluorocarbons). Vast arrays of pulsed lasers at mountain altitudes would launch intense infrared beams into the atmosphere. The laser beams would then selectively destroy CFC molecules in the atmosphere through multiphoton dissociation. Due to the low atmospheric concentration of the CFC's, any process to remove them must be highly selective and cannot afford to waste energy in reactions involving any of the far more abundant non-CFC molecules in the atmosphere. The suggested laser scheme then depends first upon finding bands of strong laser-light absorption of the laser light by non-CFC molecules in the atmosphere is virtually absent. Computer calculations making use of an extensive atmospheric-gas infrared cross-section database suggest that 90% transmission over 50-kilometer paths would be possible through dry atmospheres. Still, a factor of 10 or 20 greater efficiency for the laser-CFC dissociation process is needed to bring the projected costs down to where the plan would merit serious consideration.