it may happen if the windows are not close all the way up, or some other reasons..... wat you can do is to switch the air con all the way to full blast and leave it on till all the white gas is gone... dun worry there is nothing wrg with it... If u are in doubt or worry tat something is wrg.... just drive your car to any petrol kios tat offer air con servicing and ask them to look into this.... But i dun think it is neccessary

unless of cos the problem happen frequently.... or there is a leakage in air con gas...