Is ventilation necessary and sufficient for acceptable indoor air quality?

The role of ventilation in achieving acceptable indoor air quality is examined in the light of emerging challenges, alternative mitigation strategies and performance indices within the spatial and time matrix of the indoor environment. By considering the source of contaminants, their nature, transportation mechanism and participation in source-sink relationships, several studies have shown that it may not be feasible nor adequate to rely on ventilation alone to attain the desired level of exposure, especially with respect to airborne aerosolised droplets with infectious potential. Nonetheless, until a full characterisation of the contaminants and appropriate mitigation strategies are developed and effectively implemented, ventilation provides the generic dilution that is necessary to achieve exposure levels that are within desirable levels.