My ceiling fan blades collect a strange white powder instead of normal dust. What is it?

Ceiling fans are a staple in many homes, providing much-needed cooling and air circulation. However, they also serve another, less desirable function: collecting dust. While most people expect to find a layer of dust on their fan blades, some homeowners report discovering a bizarre white powder instead. This can be perplexing and even alarming, leading many to wonder what exactly this substance is and whether it poses any health risks