Have you noticed dark lines at the edges of your carpet?
Those dark areas are a sign of infiltration. Infiltration occurs when the air being forced into the room is escaping through small cracks under closed doors and wall frames. When this air is forcing its way through the carpet it is leaving behind small particles and pollutants that will eventually turn the carpet black. Common pollutants include cooking smoke, dust from uncleaned air ducts, and cigarette or candle smoke. Household Tips Guide says infiltration can occur no matter how much you vacuum It is not a sign of a dirty home, but it will be difficult to clean.
Can infiltration be prevented?
According to The Spruce, changing the furnace or air conditioner filter by the recommended time frame can help. You could also consider sealing the gaps between the wall frames. This is usually done with a foam sealant. If the gap is too large the carpet will be pulled up and then re-installed after sealing. Cutting back on the amount of smoke in your home will also help. Burning fewer candles and smoking outside are steps in the right direction. Finally, having your air ducts professionally cleaned on a regular basis is the best preventative action that you can take.
Can those dark lines be removed?
The particles and pollutants causing the dark lines are very small and if they have become noticeable than it is time to call a professional cleaning company. A cleaning company will have all of the specialty tools and cleaning solutions to get the dark lines out of your carpet.