機器
environmental
air
atmosphere
building
chemical
chimney
climate
condensation
contamination
danger
dirty
ecology
energy
environment
environmental pollution
factory
gas
global
harmful emissions
hazardous
human
industrial
industry
issue
landscape
modern
ozone
pipes
pollute
polluting
pollution
production
resource
river
seedling
silhouette
sky
smog
smoke
smokestack
smoking pipe
station
steam
structure
technology
toxic
trees
warehouse
warming
wooden
work