What is cause of puff of white smoke through the tailpipe when I accelerate?

Have you noticed your coolant level going down over time? If they white smoke is constant or consistent, and does not go away after the vehicle warms up, you may have a failing head gasket. Best thing to do would be to contact a local shop for a confirmation diagnosis! http://repairpal.com/volvo-within-10-miles-of-arcadia-california-91006