air
atmosphere
background
building
business
chemical
chimney
climate
cloud
coal
contamination
damage
danger
dioxide
dirty
ecology
emission
emissions
energy
environment
environmental
exhaust
factory
fuel
fumes
gas
global
global warming
industrial
industry
manufacture
manufacturing
nature
pipe
plant
pollution
power
power station
sky
smog
smoke
smokestack
stack
station
steam
technology
tower
toxic
warming
white