Ford 2003 Mustang Owner's Manual page 106

Starting
Engine exhaust, some of its constituents,
and certain vehicle components contain or
emit chemicals known to the State of California to
cause cancer, and birth defects or other
reproductive harm.
Important ventilating information
If the engine is idling while the vehicle is stopped in
an open area for long periods of time, open the
windows at least 2.5 cm (one inch).
Adjust the heating or air conditioning (if equipped)
to bring in fresh air.
Improve vehicle
ventilation by keeping
all air inlet vents clear
of snow, leaves and
other debris.
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