How does a Carbon Monoxide detector work? I know that a smoke detector monitors changes in the levels of particulates striking the sensor, but I do not believe that this is the same method of operation for a CO detector. So please help me, how does it work?
IIRC, some sort of radioactive material is involved.
Carbon Monoxide is flammable(Reducing for you chemical types). There is a small heating element that is monitored for change in resistance that would accompany an increase of a flammable gas.
This change in resistance is brought about by a chemical reaction with the CO that adds electrons to the heater (actually a semiconductor) which lowers the resistance, which is measured. This allows for a reasonable estimate of the amount of CO in the air.
This is most likely the type in your home. They are not too accurate but are better than nothing. There are other more accurate ways to measure but they require replacement of the sensors.