Ask A Scientist© Environmental Science Archive

Author:     rlsmith
Text:       What are the chemicals that harm atmospheric ozone? What waste 
disposal activities produce these chemicals?

Response #: 1 of 1
Author:     Mark Fernau
Text:       The guilty chemicals are the chlorofluorocarbons ("DuPont's Freon (TM)") such as 
cfc-ll, cfc-12, and others, the halons (used to extinguish fires), methyl 
bromide (a pesticide), carbon tetrachloride, methyl chloroform, etc. CFCs are 
used in aerosol cans (mostly overseas) as propellants, to make polystyrene foam for 
packing, car seats, etc., to clean circuit boards, as refrigerants in air 
conditioners and chillers and refrigerators, etc. The chlorine and bromine 
molecules eventually break off in the upper atmosphere and react to destroy 
ozone. They are being replaced by less harmful substitutes.  Methyl bromide is 
emitted when it is sprayed on fields. Halons are emitted when sprinkler 
systems go off that have halons in them, such as those that protect computer 
rooms. CFCs are released in waste disposal when cars and refrigerators are 
broken up in junk yards, when polystyrene foam is broken up, etc. They are also 
released by leaks and during servicing.