air
atmosphere
blue
building
burner
chemical
chimney
coal
dirty
ecology
electricity
emission
energy
environment
exhaust
factory
fence
fuel
fumes
gas
global
industrial
industry
landscape
lights
manufacturing
metal
metallurgical
oil
panorama
petroleum
plant
pollution
power
production
road
sky
smog
smoke
stack
steam
tank
technology
tower
toxic
train
vapor
warming