6. Discussion and conclusion As shown in this article, there arefive indices that can be used to assess the performance of a ventilation system regarding air change rate, pollutant removal, heat removal, exposure and air distribu-tion. The air exchange effectiveness is the effectiveness of different ventilation systems in delivering the supply air to a particular point in a room (for example, how quickly the air in the ventilated space air is changed by fresh air). While the ventilation effectiveness for the removal of contamination is defined to express how efficient the pollutant is removed in the occupied zone or in the breathing zone. Moreover, ventilation efficiency for the removal of heat is defined to show how efficient the heat will be removed by the ventilation airflow. As for personalised ventilation, the exposure effectiveness is defined to see how the occupant is protected from the exposure to the pollutant source. The air distribution system has a major influence on various indoor environment parameters, such as thermal comfort, indoor air quality, energy efficiency. The assessment of air distribution depends on the purpose of the airflow distribution, which might need different indices, like ADPI, ADI or ADINew. In addition, the performance of different ventilation systems will be determined by their specific tasks and such systems could also be assessed by different indices.