Eight studies have investigated how ventilation rates influence occupants perception of indoor air quality, for example, their rated level of acceptability of the indoor air. Worse perceived air quality was associated with lower ventilation rates in seven of eight studies. These studies suggest that perceived air quality improves as ventilation rate increase up to 40 cfm per person. For more information see LBNL-43334, Association of ventilation rates and CO₂ concentrations with health and other responses in commercial and institutional buildings.

Table 2 summarizes the studies with measured carbon dioxide concentrations and health outcomes of perceived air quality.

Frequent significant associations

• 20 of 27studies found VR < 10 L s-1 per person associated with worsening of sick building symptoms (7 found dose-response)
• 6 of 7 studies found worsened Perceived Air Quality at lower VR
• 4 of 4 studies found increased respiratory illness or absence at lower VR
• No threshold VR identified

Significant increase in risks

• Largest study found 30% decrease in respiratory and eye symptom prevalence for 5 L s-1 per person increase in VR
• In four of four studies, 50% or higher increase in respiratory illness or absence

Performance

• In laboratory research, aspects of work performance improved a few % with higher VR