Ventilation and performance in office work

Abstract

Previous work in the US (Persily and Gorfain, 2004) and Europe (Bluyssen et al., 1996) show large variation in measured ventilation rates between buildings and within buildings (Teijonsalo et al., 1996).In a significant fraction of buildings, particularly schools, the ventilation rates have been below guideline and standard values (Shendell et al., 2004).The outdoor air ventilation rates may be intentionally low because of design criteria or to save energy.Particularly in the US, air handling systems with no economizer and with a high percentage of recirculated return air in the supply air may provide low outdoor air flows.Some of the effects of ventilation rates have been long recognized.An increase of ventilation rate usually results in better perceived air quality and a lower concentration of indoor generated pollutants.Low ventilation rates generally lead to higher prevalences of adverse health effects, including SBS symptoms and air borne infectious diseases (Seppa¨nen et al., 1999).We have previously Abstract Outdoor air ventilation rates vary considerably between and within buildings, and may be too low in some spaces.The purpose of this study was to evaluate the potential work performance benefits of increased ventilation.We analyzed the literature relating work performance with ventilation rate and employed statistical analyses with weighting factors to combine the results of different studies.The studies included in the review assessed performance of various tasks in laboratory experiments and measured performance at work in real buildings.Almost all studies found increases in performance with higher ventilation rates.The studies indicated typically a 1-3% improvement in average performance per 10 l/s-person increase in outdoor air ventilation rate.The performance increase per unit increase in ventilation was bigger with ventilation rates below 20 l/s-person and almost negligible with ventilation rates over 45 l/sperson.The performance increase was statistically significant with increased ventilation rates up to 15 l/s-person with 95% CI and up to 17 l/s-person with 90% CI.