air
bad ecology
blue
chemical
chimney
climate
concrete
copy space
dioxide
dirty
ecology
electricity
emissions
energy
engineering
environment
environmental
exhaust
factory
fumes
gas
global
global warming
industrial
industry
infrastructure
manufacturing
ozone
petrochemical
pipe
plant
poison
pollute
pollution
power
power station
production
sky
smog
smoke
station
steam
structure
technology
tower
toxic
warming
waste
white