Q: Aircon blowing out white stuff.

There shouldn’t be any dangerous materials in the AC system. But it is possible that you have a buildup of dust or even mold. Your car has a cabin air filter that is supposed to keep anything out of the heat exchanger box, but if something is already in there, the cabin filter won’t stop it. In some conditions, the filter itself could be breaking down into dust. Believe it or not, one of the big problems we see in automotive air conditioning is mice. They love to go down the little tunnels and build nests. If you have mice you will notice a distinct "mousy" smell in the debris. I think the first step is to replace the cabin air filter. You can contact Your Mechanic to have a technician come right to your home or office and do the job for you. and let you know if anything further might be required.