Effect of a new ventilation system on health and well-being of office workers.

Examines the effect of a new, individually controlled ventilation system on employee symptoms. Two groups of employees were studied in one office building with mechanical ventilation, with one group the control. Individual control of the workspace ventilation was given to the intervention group. The new system gave higher air velocities, more variable temperatures, and higher concentration of airborne dust and fungal spores. Nevertheless, after four months, employees reported fewer symptoms. After sixteen months, employees reported increased productivity (11%) in contrast to a reduction in the control group (4%).