In 2005 the German Asthma & Allergy Federation (DAAB) carried out tests to compare air quality between carpeted and smooth floored rooms. The investigation was based in and around the Rhine/Westphalia area of Germany and consisted of 100 randomly selected private homes. The rooms tested were bedrooms, living rooms and children's rooms ( play rooms) if available. The split between smooth and carpeted flooring was 64% smooth floor and 36% carpeted, which is in direct proportion to that found across the country.
To ascertain the dust level a 16 channel laser particle analyser was used, which captured and tested all fine dust broken into 10µm particle diameter in the air. In particular it was determined that the measuring groups were 0.3µm, 0.5µm, 0.7µm, 1.0µm,1.5µm, 2.0µm, 2.5µm, 3µm, 4µm, 5µm, 6, 7, 8, 9, and 10µm(1µm is equal to 1 thousandth of a meter). During the exercise dust was gravimetrically seized by means of a vacuum pump which captured the particulate matter through a filter medium. The test results, reported by Dr Dipl-Ing Adreas Winkens (VDI Gesellschaft Umwelt und Innenraumananalytik GUI Mönchengladbach) show that the fine dust matter present in a smooth floored environment was at 62µm, while the carpeted rooms showed a level of 36µm. The European safe recognised level is 50µm.