environmental
burning
business
chemical
chimney
city
coal
commercial
condensation
construction
distillery
electric
electricity
energy
environment
factory
fossil
fuel
fumes
funnel
gas
gasoline
generation
generator
heat
industry
manufacturing
midair
natural
nature
oil
pipe
plant
pollution
power
powerhouse
refinery
risk
sign
sky
smog
smoke
station
steam
steel
tall
technology
towers
trail