What is black dust on windowsill and how to stop it?« Back to Previous Page

That's most likely a fine accumulation of black soot and dust, a common issue in Dubai due to desert sand, construction activity, and vehicle emissions. The fine particulate matter infiltrates through micro-gaps in the window frame. The afternoon sun heats the frame, creating thermal expansion and contraction that actively pumps this dust out, leaving the black, powdery line you're seeing.

For cleaning, avoid dry dusting as it will just push it into the air. Use a damp microfiber cloth with a small amount of mild detergent or a vinegar solution to lift the dust without smearing. You may need to gently scrub the seam where the frame meets the wall.

To stop it from returning, the permanent solution is to seal the window frame. After a thorough cleaning and ensuring the area is completely dry, apply a high-quality, flexible silicone sealant along the interior seam. In the UAE climate, choose a UV-resistant and mold-resistant formula to withstand the heat and humidity.

For a persistent issue or if you suspect the dust is also infiltrating your AC system and affecting indoor air quality, a professional inspection can identify all potential entry points. In severe cases, this dust can mix with indoor humidity and organic material, creating a more stubborn residue that requires specific cleaning agents.