Cross-Section of a Carpet This is a very low power (14x) magnification scanning electron micrograph (SEM) of a cross-section of a piece of carpet that came from the basement of a home. The owner was away on vacation when the air conditioning condensate pump broke, allowing water to soak into part of the two-month-old carpet. When the owners returned, the home and basement smelled musty. Note the lack of any type of particulate matter. © 2005 Jeffrey C. May
			Mold on Carpet Fibers This is the top of the carpet fibers at higher magnification (150x). At the right and near the top of the SEM, you can see two thin irregular cellulose fibers. The many (larger) smooth tubes are the tops of the nylon carpet fibers. One fiber at the center is covered with the fine, irregular growth of mold hyphae. © 2005 Jeffrey C. May
			Mold on Carpet Fibers This SEM at high power (450x) illustrates the mold hyphae wrapped around a nylon carpet fiber (like ivy on a pole) with an aerial projection. The mold is growing on nutrients in the dust settled on the fiber, not on the carpet fiber itself. © 2005 Jeffrey C. May
			Carpet Fibers At high power (2000x), this SEM illustrates the base of the aerial projection shown in the previous SEM. Individual round spores can be seen. The rope-like structures are the mold hyphae. © 2005 Jeffrey C. May
			Wool Carpet Fiber This is an SEM (2000x) of the surface of an approximately 27-micron diameter wool carpet fiber from an office. Wool, like many hairs, consists of an interior cortex surrounded by a sheath called the cuticle. The cortex consists of interlocking finger-like tubes with sharp ends, and the cuticle consists of plates, like the scale of a snake. The cuticle of some wool fibers deteriorates, releasing fragments. The smallest fragments in the SEM are about 2 microns; these can become respirable, airborne irritants. © 2005 Jeffrey C. May
			Wool Carpet Fiber An SEM (1000x originally) of a deteriorated wool carpet fiber. The cuticle has fallen away, and the cortex fibers are visible. These fibers can also become airborne irritants when they break up into smaller fragments. The concentration of these particulates above an old wool rug can be hundreds of thousands per cubic meter of air. Symptoms caused by these particulates include eye irritation and coughing. Wool may be itchy because of the physical symptoms associated with the sharp ends of the cortex fibers; exposed cortex fibers at the end of a hair are also responsible for the appearance of “split ends.” © 2005 Jeffrey C. May
			Cat Hair with Paint Sphere Spheres like this appear in air and dust samples, varying in size from 10 to 70 microns. In a light microscope, they look like circular colonies of bacteria but in reflected light the spheres are the color of the paint, usually white. The bacteria-like particles are titanuam pigment particles. Note the flat portion where another paint sphere was attached at one time. These spheres are produced by spray-painting. © 2005 Jeffrey C. May
			Carpet Beetle I caught this carpet beetle larva in a vacuumed dust sample from a rug. It is eating a piece of food, possibly a skin scale, surrounded by colored cotton fibers. © 2005 Jeffrey C. May