Comparison of air exchange efficiency and contaminant removal effectiveness as IAQ indices

Recently indoor air quality (IAQ) became an important issue and as a result researchers have developed a large number of different air quality indicators. This study focuses on air exchange efficiency (εa) and contaminant removal effectiveness (ε) as suitable indicators for use in design and on-site measurements. These two IAQ indicators were numerically studied and compared for five typical indoor spaces with different ventilation strategies and contaminant sources. Overall, more than fifty different simulations were performed. The results show that εa is appropriate for general evaluation of ventilation strategies for spaces with unknown contamination sources, while ε provides more informative results for removal of contaminants with known position and generation rates. Nevertheless, certain correlations between εa and ε exist. Based on the results of this study, designers could select an air quality indicator that is more appropriate for their particular application.