air
back
blue
building
bussiness
chimney
clear
climate
cloud
contamination
copy space
dioxide
dirty
ecology
economic
economy
electricity
emissions
energy
environment
environmental
exhaust
factory
fumes
gas
global
growth
industrial
industry
lit
manufacturing
mood
nature
nobody
pipe
plant
pollution
power
production
recession
representing
sky
smoke
smoking
steam
technology
trade
vapor
warming
waste
white