UV light technology
has been successfully used for the disinfection of drinking
water for years. Applications for air disinfection with
the use of UV light
technology include: commercial air treatment in hospitals,
clean rooms, meat
packing plants, bakeries, dairies, breweries, bottling
plants and large commercial
This product testing
study evaluates the effectiveness of air health
sanitizer in reducing the levels of bacteria with a
single pass through a simulated
air duct system. This device is designed to irradiate
air as it circulates
through the home, so the single pass evaluation is the
worst-case scenario use
of this device. air in the home will pass through
the heating and air
conditioning system many times a day, as air is
circulated throughout the
home. Knowing the effectiveness of air health
in a single pass application,
enables us to project how effectively the device will
treat air with multiple
passes a day.
Material and Methods:
marcescens (ATCC 14756) was chosen as the
bacterium. The distinctive red colonies made it easy
to evaluate from any
background organisms. A raw test suspension of the organism
95,000 CFU/ml was used. As dispersed into the test system,
yielded bacterial counts of 269 CFU/ft 3 @ 500 ft/min
airflow and 107.5 CFU/ft 3 @
1000 ft/min airflow. (CFU = Colony Forming Units)
An 18" x 18" galvanized air duct, 38 feet
long was constructed
as the test chamber (see Figure
1). A fan was mounted at the exit end of the
chamber and the treated air exhausted to the outdoors.
To reduce contamination
of the intake air, all air intakes on the exhaust side
of the building were sealed.
The exhaust fan was equipped with a flow adjustment
to allow for adjustable air
speeds measured in feet per minute (FPM) through the
rate. airflow rate through the ductwork was
adjusted to two
nominal velocities of 500 ft/min and 1000 ft/min. airflow velocities were
measured at the center of the duct at the intake end
of the test duct.
An atomizing humidifier spray nozzle mounted at the
center of the test duct intake was used to distribute
the organism into air
stream. The application flow rate was 0.45 gallons per
A home health products air health
air sanitizer model AH-1 was mounted
onto the center of the side of the test duct 6 feet
from the exit end of the chamber.
The bulb is a UVC germicidal bulb (non ozone producing)
16 inches long with a
UV output rating of 62 mW/cm 2 at 1 meter from the bulb.
method. An Andersen N6 single
stage "bioaerosal" sampler was
used to take air samples and distribute the sampled
air onto agar medium.
The test medium was Tryptic Soy Agar from PathCon, Inc.
air sampling pump
airflow rate was 1 CFM.
The Anderson sampler
method requires corrections to the actual colony counts
the plates. This provides a more accurate measure of
the bacteria per cubic foot
of the sampled air. In the following tables the Serratia
marcescens Positive Hole
Count values are the actual plate counts and the Corrected
Particle Count values
are corrected value based on Anderson correction tables.