environmental
air
atmosphere
background
blue
carbon
chemical
chimney
climate
contamination
dioxide
dirty
ecology
emission
emissions
energy
environment
exhaust
factory
fuel
fume
fumes
gas
global
high
industrial
industry
manufacturing
outdoors
pipe
pipes
plant
pollute
pollution
power
red
refinery
sky
smog
smoke
smokestack
station
steam
technology
tower
toxic
vapor
warming
waste
white