Carbon Monoxide Detector and strange smell

[frscott]

I was sleeping soundly last weekend only to be awakened by my CO2 detector. I had just turned the heat on for the winter and I think (thought) it just had some dust as there was a slight dingy smell coming out of the vents. I reset the alarm and went back to sleep (after cracking some windows) and slept well with no more alarms. The other night the alarm went off again, even after reseting it went off again and again, the smell was greater this time so I abandoned ship and slept elsewhere. What little I know of CO2 is that it does not smell, so what could this be??? How do you track down a CO2 leak if that is what it is??