abstract
abstraction
acid
air
atmosphere
changing
chimney
climate
cloud
co2
coal
damage
dark
deleterious
dioxide
dirty
ecological
emission
emissions
environment
environmental
exhaust
factory
fuel
fume
fumes
gas
global
growth
harmful
industrial
industry
intoxication
nature
poison
poisoning
pollutant
polluted
pollution
power
sky
smog
smoke
steam
warming