Air Filters for Filtration, Ultraviolet Lights for Purification
Studies show that air inside our schools can be 100 times more polluted than outside air -
underscoring the importance of a proper air filter system. Modular units should employ
two tools that help improve air quality; the 30 percent pleated filter and ultraviolet light.
Everyday, a student's lungs can process up to 1,000 cubic feet of air, or the equivalent of
30,000-quart containers per day. Asthma, allergies, and other afflictions are triggered by
the repeated exposure of the lungs to small doses of chemical substances. Airborne
contaminates cause diseases such as influenza, hepatitis, tuberculosis, and pneumonia.
Combating health hazards found in the air begins with choosing the proper air filter. Air
filters clean solid particles from the air and range from inexpensive, glass fiber disposable
filters that trap large particles to 30-percent pleated filters, recommended for modular
units. A 30-percent pleated filter collects particles as small as 10 microns in size. Pleated
filters provide additional surface area to collect particles and also are disposable.
Washable filters are not well suited for the modular industry.
Ultraviolet (UV) light is another weapon in the battle against an unhealthy environment.
While air filters remove harmful solids, ultraviolet lights purify the air, removing
chemicals and biological contaminants. Sunlight is the most effective natural air purifier
known to break down chemical and biological contaminants and UV lights work in a
similar fashion through both UVV and UVC capabilities.
UVV destroys chemical contaminants (solvents, formaldehyde, VOCs) by photooxidation
while UVC destroys biological contaminants (yeast, mold, bacteria, and
viruses) by destruction of the organism's DNA. Since airborne organisms have short life
spans, their population decreases rapidly when reproduction is inhibited by UVC.
Another interesting fact about UV air purification systems is that efficiency decreases
farther away from the bulb. This decrease occurs very quickly and is not linear; the "kill
rate" right next to the quartz UV bulb is 100 percent, it is 60 percent efficient .4 inches
from the bulb, and 20 percent efficient two inches from the bulb. While this mere 20%
efficiency at only two inches from the bulb may sound troubling, consider that air is
constantly circulating and passes through the system more than once.
Lastly, to get the most from your UV system, it is important to use a UV light that has
both WVV and UVC capabilities. UV bulb manufacturers normally use two different
types of quartz glass in the bulb: approximately 20 percent for UVV and 80 percent for
UVC capabilities. The life expectancy of a UV bulb sho uld be about 12,000 of run time.
If the blowers were to run 24-hours-a-day, the bulb life span would be approximately 15
Keep in mind that your building will be occupied by asthma and allergy sufferers who are
extremely sensitive to contaminants such as dust, mold spores, odors (chemical and
biological), bacteria and second hand smoke, so inspect/change your air filter and update
your knowledge on UV and other IAQ issues so everyone breathes a little easier.
By: Maury Tiernan