White smoke from your exhaust is often a sign that coolant is getting into the parts of the engine that it shouldn't. Check to see if your coolant levels are going down.
Black smoke looks more dramatic but is usually related to the fuel mixture and burning too much fuel. Check your filters and whether any air pipes are split.
Blue smoke is a sign that you are burning oil, check your oil levels and get to a garage!
Your exhaust fumes tell you a lot about the health of your car, if you're worried pop in and have a word with the team here.