air
architecture
blue
building
carbon
chemical
chimney
climate
clouds
contamination
danger
destruction
dirty
earth
ecology
emission
energy
environment
environmental
factory
fume
fumes
gas
generate
global
greenhouse
hazardous
industrial
industry
manufacturing
ozone
pipe
plant
poison
pollute
polluting
pollution
power
rain
refinery
sky
smog
smoke
smokestack
steam
steel
tower
toxic
vapor
warming
waste