Why do newer buildings seem to have more IAQ problems than older ones?
While this is not necessarily true, newer buildings (post 1970’s) are built with energy conservation in mind. There are many ways to minimize energy cost due to cooling and heating losses, however, one common way is reduce the building leakage factor. Through better construction and insulation techniques, this action, in effect, makes the building tighter or better sealed against natural air exchanges between indoor and outdoor air through the process known as infiltration. Additionally, some buildings practice reduced outdoor air ventilation policies. These conditions and more work to reduce the dilution of indoor air from infiltration (that older buildings may have) allowing ambient concentrations of indoor contaminants to rise. Normal sources of indoor contaminants include office equipment, furnishings, construction materials, occupants, etc.
