Did the german public know about the concentration camps?

The German public claim that they did not know about the concentration camps. However, those who lived near the camps had about half an inch of ash on their cars and homes when they woke up in the morning. They did not know why but it was from the burning that went on in the camps.

I think the nazi's tried hiding it so no

Sorry i dont know hope you do good can you mark me as brainlist