Carpet Ghosting Adjacent to Wall
                
              
              
                Macrophotograph
                
Definition/Function:
                Significance in the Environment:
                The black edge on carpet next to the wall tends to be due to two different effects. The
                first is the
                inability of carpet vacuum cleaners to get close to the wall or to effectively knock the
                dust free from
                the carpet fibers at that location. A wand attachment can help remove those particles
                and the discoloration.
                The second cause is due to the wall "breathing". As air pressure changes in the room due
                to changes in
                temperature or atmospheric air pressure, the air in the wall cavities has to
                equilibrate. The base of
                the wall is not sealed so that air can enter or escape as need to equilize the pressure
                in the wall with
                that in the room. Small particles, such as soot, are filtered out of the air and stick
                to the carpet fiber.
                This also happens with wall outlets and switch plates.
                Characteristic Features:
                Associated Particles:
                References: