air
atmosphere
blue
building
chimney
cloud
co2
coal
colorful
commerce
condensation
construction
dioxide
ecology
electricity
emissions
energy
environment
exhaust
factory
fog
fume
fumy
gas
generation
greenhouse
industrial
industry
nobody
pipe
plant
pollute
polluted
pollution
power
rain
red
sky
smog
smoke
smokestack
station
steam
sunlight
technology
thermal
tower
toxic
vapor
white