air
atmosphere
blue
building
chemical
chemicals
chimney
climate
cloud
contamination
damage
dioxide
dirty
ecology
emissions
energy
environment
environmental
exhaust
factory
fuel
fume
fumes
gas
global
heat station
high
industrial
industry
manufacturing
nature
pipe
plans
pollution
power
production
refinery
sky
smog
smoke
smokestack
station
steam
technology
tower
toxic
vapor
warming
waste
white