air
atmosphere
black
chemical
chimney
construction
contamination
damage
danger
dioxide
dirty
ecology
emissions
energy
environment
environmental
exhaust
factory
fire
fog
fuel
garbage
gas
global
heat
hot
industrial
industry
inhaling
manufacturing
nature
pipe
plant
poison
pollute
pollution
power
production
sky
smog
smoke
smokestack
sun
technology
tower
toxic
warming
waste