Impact of changing the floor material on air quality in an office building.

Perceived air quality, symptoms, and perception of the environment were studied in a naturally ventilated office building in which a felt carpet was substituted by linoleum on the first floor and by polyolefine floor tiles, known from previous studies to be a low-polluting floor material on the second floor, while the felt carpet remained unchanged on the ground floor. A panel of 36 untrained subjects occupied the offices on each storey for a period of one hour in a balanced design on a day when normal occupants were absent. The subjects assessed the indoor climate on four different occasions, as follows: on entering the offices they immediately assessed the perceived air quality and after they were seated they evaluated symptoms experienced at that time; 20, 40 and 60 minutes after entering the offices they assessed the perceived air quality, as well as their symptoms, and the condition of the environment. Finally the subjects stated on which of the three floors they would prefer to work. A change of floor material significantly decreased the percentage of those dissatisfied with the perceived air quality from nearly 30% in offices with felt carpet to approx. 15% in offices with polyolefine floor material, and also decreased the sensory pollution load caused by the building from 0.10 olf/m2 in offices with felt carpet to 0.02 olf/m2 in offices with polyolefine floor tiles. A preference vote revealed that subjects selected offices with polyolefine floor covering as having the best air quality. These results confirm that decreasing pollution sources is an obvious measure for improving the air quality in buildings.