environmental
aerial
air
antenna
blue
chimney
clear
climate
communication
condensation
dioxide
dirty
ecology
emissions
energy
environment
exhaust
factory
flue
funnel
global
green
greenery
heat
heating
industrial
industry
pipe
pollution
power
receiver
sender
sky
smog
smoke
smoking
stack
station
steam
stovepipe
system
technology
tower
transducer
transmitter
trees
up
vegetation
warming
white