Our detector has gone off a number of times for what seemed to be no reason. Sometimes I hold the reset button and it will cycle through the reset process and won't go off again. At other time, when I'm sure there isn't a leak of CO/LP it will still go off after being reset a number of times. In those situations I've disconnected the power, let it sit, reconnect the power and that seem to clear things up for a while.
I think as you said, there could be things in the environment like hair spray, nail polish, perfume, etc. (women's stuff :) ) that will set of a detector and take some time to clear.
My main concerns with respect to CO/LP would be at night when we are sleeping. During the day I'm the primary CO/LP detector and the electronic detector is secondary.