Turk B, Powell G, Casey M, Fisher E, et al
Bibliographic info:
USA, Washington DC, Healthy Buildings/IAQ '97, 1997, proceedings of a conference held Bethesda MD, USA, September 27 - October 2, 1997, Volume 1, pp 155-160

Mechanical ventilation systems, designed to meet ASHRAE's Standard 62-1989 and to modify building pressures, were installed in two New Mexico elementary schools to reduce elevated levels of indoor radon, carbon dioxide, and airborne particles. Although the systems did not meet design conditions for outdoor air delivery, ventilation rates were increased by factors of 2 to 4 over pre-existing natural ventilation rates, and levels of indoor air pollutants were significantly reduced. Operation of the ventilation systems reduced radon levels to less than 70 Bq m·3 and average mass (PM10) and count (particles greater than 0.5 μm) concentrations of airborne particles approximately 10 to 70%. Average pre-existing indoor concentrations of carbon dioxide (C02) were reduced from 20 to 60% by the additional ventilation, but not always below ASHRAE' s guideline of 1000 ppm. Estimates for the additional energy cost to operate the ventilation systems ranged from $700 to $1300 per year.