Indoor air quality is important in commercial buildings to maintain employee health, well-being and productivity, and avoid employer liability. The most common method to improve indoor air quality in commercial buildings is to use outside ventilation air for dilution of the inside air. Unfortunately, this method is associated with a significant energy load.
Commercial buildings that attempt to reduce the outdoor air intake rates to save on energy costs without adequately addressing indoor air quality requirements, frequently experience degradation in indoor air quality. As a result, there often is a perceived conflict between energy-efficient ventilation and indoor air quality. However, emerging indoor air purification technologies can allow for reductions in outdoor air ventilation rates without compromising indoor air quality.
The objective of this paper is to identify indoor air purification technologies that allow for reduced outdoor air intake rates, while maintaining acceptable levels of indoor air quality. To that end, the paper begins with a brief overview of energy use associated with space conditioning in commercial buildings. This is followed by a discussion of the perceived conflict between energy-efficient ventilation methods and indoor air quality, and how the Ventilation Rate (VR) Procedure and the Indoor Air Quality (IAQ) Procedure in ASHRAE Standard 62.1-2007 attempt to address this perceived conflict. Thereafter, the paper presents indoor air purification technologies that allow for reductions in outdoor air intake rates if used with the IAQ Procedure.
Specifically, media filtration, gas sorption, bipolar ionization, and photocatalytic oxidation are discussed. A few examples of installations of media filtration coupled with either gas sorption or bipolar ionization in commercial buildings are presented to demonstrate the effectiveness of the IAQ Procedure in allowing for the reduction in outdoor air intake rates by 40-75% while maintaining acceptable levels of indoor air quality. Finally, the paper ends with recommendations on how to further the use of the IAQ Procedure in commercial buildings.