air
atmosphere
carbon
change
chemical
chimney
climate
cloud
co2
contaminate
contamination
could
danger
destruction
disaster
ecology
emission
environment
environmental
exhaust
factory
foliage
fumes
fuming
gas
global
harmful
industrial
manufacture
metal
nature
pipe
plant
pollution
power
production
sky
smoke
smokestack
smokestacks
stack
station
steam
steel
technology
tower
toxic
trees
warming
waste