Sir velOcity,

May I ask as to when was the last time you have your car's A/C serviced? Other than the suggestions / discussions given by our Tsikot guru's above, your ac system (evaporator) might be already dirty causing the restriction of air. Air restriction sometimes causes the coil to abnormally reach very low temperatures (specially if the temp settings are very low / or max) causing very high temp difference between the coil and ambient, thus the smoke.