against
air
blue
building
carbon
chemical
chimney
clear
climate
cloud
coal
construction
contamination
day
dioxide
ecology
emission
environment
environmental
exhaust
factory
fuel
fume
gas
generation
global
heavy
industrial
industry
nature
pipe
plant
pollution
power
production
refinery
sky
smog
smoke
smokestack
stack
sunshine
tall
tower
toxic
vapor
warming