air
black
burning
carbon
chemical
chimney
city
climate
cloud
coal
condensation
construction
damage
danger
dioxide
dirty
ecology
emit
environment
environmental
exhaust
factory
fuel
fumes
gas
generation
generator
global
heavy
industrial
industry
kyoto
layer
nature
ozone
pipe
plant
polluting
pollution
power
smog
smoke
steam
threat
toxic
trail
tube
ukraine
warming
waste