environmental
air
atmosphere
big
black
blue
branches
carbon
chemical
chemistry
chimney
climate
cloud
contamination
copy
damage
dioxides
dirty
ecology
economy
emission
energy
environment
exhaust
factory
fuel
fumes
gas
globally
high
industrial
industry
manufacturing
nature
pipe
pollution
power
refinery
sky
smog
smoke
smokestack
space
steam
technology
tower
toxic
trees
vapor
warming
waste
white