I keep sweeping up fine white powder under my vents and it keeps coming back. What is it?

11. Cleaning Up the Existing Dust Without Blowing It Back Into the Air
Cleaning up fine white dust without reintroducing it into the air requires careful techniques. Use a vacuum cleaner equipped with a HEPA filter to capture as much dust as possible without releasing particles back into the environment.
For surfaces around vents, a damp microfiber cloth can effectively trap dust without spreading it. Regular cleaning and maintenance of HVAC components, such as vents and filters, also help minimize dust buildup and maintain good indoor air quality.
12. Long-Term Fixes: Sealing, Upgrading Ductwork, and Improving Filtration
For a long-term solution to persistent dust issues, consider sealing and upgrading ductwork. Properly sealed ducts prevent dust and debris from entering the system, reducing the amount of dust distributed throughout the home.
Upgrading to higher-quality filters and regularly replacing them can also improve air quality and reduce dust accumulation. Consider installing an air purifier or a whole-house filtration system for added protection against airborne particles.