One problem related to side/window air bag has been reported for the 2008 Volvo C30. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Volvo C30 based on all problems reported for the 2008 C30.
I was driving out of a toll booth and was accelerating. A tractor trailer began coming closer to me. I moved over to avoid impact with the truck. In the process my front and rear drivers side wheels rubbed against a curb causing the side airbags to deploy. There was no damage to the vehicle other than a two inch scrape on the rims. The employees in the body shop and service department stated that the airbags should not have deployed due to the wheels rubbing curb. The woman at Volvo stated that the car "detected imminent damage" which caused the airbags to deploy. I was decelerating at the time of the deployment, had I been accelerating to pass the truck I would have been killed. The investigator from Volvo stated that they moved the sensors to the wheel wells and the are more sensitive. I think this is a serious safety concern as the vehicle, upon detecting imminent danger almost killed me.