Caption

House dust. Coloured scanning electron micrograph (SEM) of household dust from Germany. The smaller fibres are from clothing, carpeting and the like. The larger fibres (lower & upper left) are hairs from humans or household pets. Also prominent in the image are flakes of human skin. Household dust also comprises fungal spores, pollen, particles of soil and sand and fibres of household coverings. Many of these substances may be allergens, provoking an allergic reaction in humans. Magnification unknown.