機器
air pollution
architecture
biomass
blue
building exterior
built structure
burning
business
chemistry
chimney
cloud
coal
dioxide
distillery
electricity
energy
environment
environmental damage
factory
fog
fossil fuel
fuel and power generation
fumes
gasoline
global warming
green
horizon
industry
metal
oil industry
ozone layer
pipe
pollution
power station
silhouette
sky
smog
smoke
smoke stack
steam
technology
tower
toxic substance
tube