environmental
air
atmosphere
carbon
chemical
chimney
climate
cloud
coal
concepts
copyspace
crisis
dioxide
dirty
ecology
environment
factory
fumes
gas
global
harmful
hazardous
heat
heating
industrial
industry
manufacturing
nature
orange
plant
poison
polluting
pollution
power
red
silhouette
sky
smog
smoke
smokestack
stack
steam
symbol
tower
toxic
warm
warming
yellow