ardent
atmosphere
black
bloat
brand
burning
carbon
chimney
cloud
copy
damage
danger
dangerous
dark
dioxide
dirty
energy
environment
environmental
factory
fire
firefighter
fireplace
flames
flammable
flock
food
fuel
gas
heat
high
hot
industry
manufacturing
nature
net
outdoors
panorama
pollution
regular
sky
smog
smoke
smokestack
toxic
violence
warm
warming
yellow