According to IICRC technical advisor Jeff Bishop: "Carpet often actually improves indoor environmental quality by trapping and holding particles, dust and other soils until routine maintenance and cleaning can remove them. However, if neglected, carpet, like any container, can become filled to the extent that it can hold no more. At that point - when the surface is agitated - it will become a releasing source for particles and dusts that can cause respiratory irritation or trigger allergies, just as can hard surface flooring when soils are allowed to build up."

Another Viewpoint on Carpet

by Jeffrey C. May, M.A., CIAQP (Certified Indoor Air Quality Professional)

Carpet acts as a dust trap, however, all the dust trapped in a carpet can never be removed by vacuuming, so when carpet is disturbed by activity, particulates are aerosolized.

Dust also accumulates on hard flooring but the surface does not trap the dust, so virtually all of it is readily removed. Therefore disturbing a clean hard surface floor never releases as many particulates as a clean carpet.

I have taken air and dust samples in thousands of structures and when there is activity on carpeting, there is always more aerosol than in spaces with solid flooring.