Building materials are often found among the major air pollution sources in buildings. One method to obtain details about the emission from materials in buildings may be based on material samples taken from the building and brought to a laboratory, where the evaluation can he supported by the use of emission test chambers. 

This paper presents a methodology for detailed field studies of the emission from building materials in existing buildings by the use of a portable micro-scale emission test chamber. The Field and laboratory Emission Cell (FLEC) provides the possibility of emission testing in the field, without damaging the building by collection and removal of material samples. The method is based on assessment of emission factors for the potential air pollution sources, one by one, in a room. The intention is to gain detailed information about the importance of different sources by comparing the FLEC results to VOC measurements in room air and outdoor air. The aim of the present study is to investigate the feasibility of the use of FLECs for source identification and to investigate the influence of the parameters time and specific ventilation rate in order to optimize the method. The work summarized in this paper was carried out as a part of the European Audit Project.