The contribution of new and used fine bagfilters to indoor air pollution has been determined in a laboratory study by a trained panel as well as by TVOC measurements. The used filters were all taken out of air handling systems which run with full outdoor air supply. The time that a used filter had been situated in the ventilation system until it was taken out and was studied in the laboratory varied from two to ten months. The new filters did not pollute significantly in comparison to the used filters. However, all used filters polluted the air instead of cleaning it.
The development of odor emission rates from EU6 classified glass fiber bag filters was studied in four air-handling units (A HU), and emissions from the same kind of filters with EU3 classified polyester prefilters were studied in two units. The filters were loaded in six AHU in downtown Helsinki. The pressure drop was measured, and the odors of the filters were evaluated by a trained panel under laboratory conditions (T= 20o C, face velocity 1. 0 m/s) every sixth week. The odor emissions of simultaneous atmospheric dust samples were also studied.