Are you sure that you need to detect only carbon monoxide ? Your question
about 'the other deaths' means that sometimes the freon leaks out of the
system into the passenger compartment ? Afaik you cannot suffocate in a
sealed car without noticing because CO2 causes you to try to get out a
long time before you run out of oxygen.

A freon detector may be harder to get by than CO. Freon is chemically
inert and will probably require some physical method to detect (like
fluorescenece or something like that). Are there freon sniffers, and if
so, what principle do they use ? Does anyone know ?

Peter

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