英文關鍵字
air
animal
birds
building
business
causes
change
chimney
chimneys
climate
commercial
companies
company
construction
contamination
damage
ecology
economy
effects
environment
exhaust
factory
flying
fumes
funnel
global
gray
harmful
hazard
health
industrial
industry
large
layer
natural
object
ozone
pipes
pollutants
polluter
pollution
product
production
smoke
smokestack
smokestacks
smoky
technology
the
throws
tubes
warming
work