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air
alphabet
atmosphere
backdrop
background
ban
business
certified
cfc
chemical
chlorofluorocarbon
compound
concept
copy
dangerous
depletion
design
earth
element
environment
equipment
free
gas
global
grass
green
guarantee
harmful
hazard
health
hydrocarbon
industry
label
letter
material
montreal
ozone
planet
pollution
production
protocol
qualified
safety
science
space
spray
volatile
warming
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