aerial
air
area
atmosphere
background
building
canal
carbon
chemical
chimney
china
climate
cooling
damage
dioxide
disasters
ecology
emissions
energy
environment
equipment
factory
fog
fumes
global
industrial
industry
manufacture
metal
mills
mountain
natural
outdoor
pipe
plant
pollution
power
river
scene
scenery
sky
smog
smoke
smokestack
steam
steel
steelworks
tower
warming
water