air
atmosphere
blue
brick
building
carbon
chimney
cloud
cloudy
contamination
damage
danger
duct
ecology
emission
energy
environment
exhaust
factory
fumes
generation
high
industrial
industry
manufacturing
masonry
old
pipe
plant
pollute
pollution
power
production
sky
smoke
smokestack
stack
stalk
steam
technology
three
tower
toxic
tube
urban
vapor
wall
warming
waste
white