The capability of a solid sorbent desiccant unit at removing selected indoor air quality-relate microorganisms from the air

Date

2004-08

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Publisher

Texas Tech University

Abstract

Throughout history, diverse cultures and societies have appreciated the importance of a clean and healthy indoor environment. In western societies today, most people spend greater than 90% of their time indoors. Reports involving buildings with indoor air-related problems have appeared increasingly in the medical and scientific literature, although this problem has been with humans for centuries. Sick building syndrome (SBS), a common term for explaining symptoms that result from individuals' exposure to poor indoor air quality (IAQ), was first recognized as an important problem affecting occupants in certain buildings in 1982. The presence of moisture, fungi, spores, and fungal growth in sick buildings has become consistently associated with SBS. Poorly maintained heating, ventilation, and air conditioning (EIVAC) systems have been recognized as sources of microorganisms, including fungi. Undesirable moisture levels and fungal growth indoors represent a public health concern inadequately addressed by building, health, or housing codes. Drying the ventilation air via the honeycomb wheel desiccant based cooling is a cost effective method of humidity control and removes statistically significant concentrations of IAQ-related microorganisms from the air. Controlling humidity is crucial for human comfort, minimizing adverse health effects associated with high humidity and maximizing the structural integrity of buildings. Several authors have stated that the use of active desiccants enhances the quality of the indoor air by helping to maintain comfort criteria (temperature, humidity, and ventilation, removing particulates and bioaerosols from the air, and removing chemical pollutants from the air. The capabilities of a rotary wheel solid-desiccant dehumidifier at removing selected IAQ-related fungal organisms from the airstream were quantified at temperatures ranging from GO^F to 36Q°F at 100°F intervals. Average removal efficiencies for viable concentrations of spores ranged from 42%-98% for Aspergillus niger, Cladosporium cladosporioides, and Penicillium chrysogenum at the four temperature settings. Average removal efficiencies for total spore concentrations ranged from 30%-95% for the same organisms and temperature settings. The results of this study show that utilizing a rotating honeycomb desiccant apparatus in conjunction with conventional air conditioning can significantly reduce the airborne concentrations of IAQ-related microorganisms delivered to the indoor air.

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