英文關鍵字
air
background
blue
building
business
chemical
chemistry
chimney
closeup
construction
dirty
ecology
energy
engineer
engineering
environment
environmental
factory
flue
gas
gasoline
global
industrial
industry
isolated
manufacturing
metal
night
oil
old
petrochemical
petroleum
pipe
pipeline
plant
pollution
power
production
refinery
sky
smog
smoke
smokestack
stack
steam
tall
tank
technology
tower
white