What would cause my Smoke Detectors to go off for 30 seconds?

I have the same setup and have had that problem about five times out of the nine years i've owned my house. It hasn't done it in the past two years though. I never was sure what caused it, but the last time I suspected maybe dust causing the detector to think it was smoke. I cleaned all the smoke detectors with a can of compressed air. I have not had problem since. I'm not sure if that's what fixed it or not. Worth a try....