In a real office environment hardcopy devices are a known source of ultra-fine particles. Registration measurements of these devices regarding their emission of VOC, SVOC and ozone are typically made in emission test chambers. Due to the controlled conditions (temperature and air humidity) the particle release is also desired to be tested the same way. The transferability of the results from the small volume emission test chamber into a high volume office is complicated by the fact that the deposition behaviour of the particles under the mentioned conditions is different. The particle concentration decay, which is not solely given by the air exchange rate in the emission test chamber, is 10 times smaller than expected from chamber experiments. It is noticeable that the particle size distribution, which shows a biomodal distribution, is not affected by different testing environments. Additionally, chamber tests provide information under controlled environmental conditions and have proven to be valuable for identifying the source of the particles.