atmosphere
blue
building
chemical
chemistry
chimney
city
climate
cloud
coal
danger
dirty
ecology
effect
emission
energy
enterprise
environment
environmental
exhaust
factory
flue
fume
furnace
gas
industrial
industry
manufacturing
misty
output
pipe
plant
pollute
pollution
power
production
sky
smog
smoke
smokestack
steam
supply
system
technology
thermal
tower
toxic
tube
vapor
waste