Based on these results, we conclude that in office buildings or similar spaces constructed using current building practices, increases in ventilation rate in the range between 0 and 10 Lsª1 per person will, on average, significantly reduce occupant symptoms and improveperceivedairquality.Increasesinventilationrate above 10Lsª1 per personup to 20Lsª1 per personmay further reduce symptoms and improve air quality, althoughthesebenefitsarecurrentlylesscertainbasedon available data. No threshold for effects is evident at 10 Lsª1 perpersonoratanyotherspecificventilationrate. As ventilation rates increase, benefits gained for occupants per additional unit of ventilation are likely to decrease in magnitude and to require larger studies for convincing demonstration. Benefits which have yet to beconsistentlydemonstratedinthisway(e.g.,forventilationratesabove10Lsª1perperson)maystillbeofsubstantialpublichealthimportance.Ventilationstandards thus may need to periodically revisit the available evidence for occupant benefits at particular ventilation rates, and the magnitude of these benefits, weighed againstthecurrentincrementalcostsofincreasingventilation. This process would be new, as minimum ventilation rates in existing codes and standards do not substantiallyreflecthealthdatasuchasisreviewedhere.