The Effect of Air Duct Sanitation on Fungal

Populations in a Residential Environment:

Phase I - Winter: Phase II - Summer

R.A. Garrison, B.S., L.D. Robertson, M.S., B.S.

S.R. Wynn, M.D., R.D. Koehn, Ph.D., 1990

Abstract

Commercial air duct sanitation services are widely available, and are advertised as being effective in reducing indoor aeroallergen levels despite the absence of published supporting data. Eight residential heat-ventilation-air conditioning (HVAC) systems in six homes and seven HVAC systems in five homes, for Phase I and Phase II respectively, were sampled to determine fungal colony forming units (CFU’s) prior to and after an HVAC sanitation procedure. The HVAC Sanitation was performed by Abbey Road Clean-Aire, Inc.*, of Fort Worth, TX. Four different houses, each with single HVAC systems, served as controls in both Phase I and Phase II studies. Two sample sets were obtained at each HVAC system prior to cleaning to obtain baseline CFU levels. The six study HVAC systems in Phase I and the five HVAC systems in Phase II received the HVAC sanitation. The HVAC systems were allowed to operate under the “normal” operating parameters prescribed by each individual house residence. No manipulation or instructions were performed to control any specific functions of the test or control HVAC systems. Post-treatment sampling was performed 48 hours and then weekly after cleaning. The HVAC systems were analyzed by exposing sterile 2% malt extract media plates at a 90 degree angle to the airflow at the air supply and air return vents. The baseline CFU’s were similar in the control and study houses. Eight weeks after sanitation, the study demonstrated an overall CFU reduction of 91.6% for Phase I and 84.4% for Phase II. With respect to air supply vents only, the study houses demonstrated a 95% reduction in CFU’s for Phase I and a 98% reduction for Phase II. An 83% reduction in total quantitative bioaerosol was determined for Phase II. No significant change in CFU values were observed over the eight-week study period for the houses selected as controls. Moreover, HVAC sanitation appeared to reduce the number of fungal colonies entering and leaving the HVAC system, suggesting that the HVAC contained a significant percentage of the total fungal load in these homes. These data suggest that HVAC sanitation is effective in reducing airborne fungal populations in residential environments.

For more information, contact: Larry Robertson
Mycotech Biological
(800) 272-3716

Melinda Allen

Video-Aire International

(888) 595-4393