air

atmosphere

black

boiler

burning

business

central

chimney

city

color

construction

ecology

electricity

energy

environment

environmental

factory

fog

fuel

fumes

gas

generation

generator

industrial

industry

landscape

light

manufacturing

nature

ozone

pipe

plant

pollution

power

production

silhouette

sky

smog

smoke

station

steam

structure

sunrise

sunset

supply

technology

tower

tube

urban

warming