atmosphere
auto
beater
car
carbon
climate
co2
combustion
damage
dioxide
dirt
dirty
dust
eco
ecology
emission
energy
engine
environment
environmental
exhaust
fossil
fuel
fume
fumes
gas
gasoline
global
green
greenhouse
industry
mechanic
monoxide
motor
muffler
object
oil
old
particle
pipe
pollution
racing
road
rust
smog
smoke
tailpipe
toxic
transport
transportation
vehicle
warming
waste