air

atmosphere

background

bad

boiler

building

burn

business

chemical

chimney

city

cityscape

climate

construction

contamination

danger

dirty

ecology

energy

engineering

environment

environmental

factory

fog

fuel

fumes

gas

global

gloomy

health

industrial

industry

landscape

large

metallurgical

metallurgy

outdoor

pipe

pipes

plant

pollution

population

power

problems

sky

skyline

smog

smoke

steam

technology

town

toxic

urban

warming

zone