A tiny speck of “living dust”. If the dust gets up and walks away from you, it is Furniture Mites. About 0.5mm long, with eight tiny legs, they infest certain types of upholstered furniture – especially vegetable fibres in damp conditions.
May cause an allergic reaction in sensitive people.
REMEDY: Heat infested rooms to an uncomfortably high temperature and thorough dry and ventilate them.
Employ a pest control company to treat the house for mite infestation.