2.1 Molecular Structure
gases, liquids, and solids are made up of elements. The fundamental
building blocks of elements are atoms, which in turn are made of
electrons, neutrons and protons...all held together by electronic
attraction. This is referred to as polarity, the principle that positive
and negative poles attract and remain bound together based upon the
strength of that attraction.
are over 100 elements known in our universe. It is the elements that
form compounds. Elements combine to form gases, liquids or solids. For
example, water is made of two molecules of hydrogen and one molecule of
oxygen. Carbon dioxide is one molecule of carbon and two molecules of
oxygen. These and all other combinations of elements are bound together
by the force of attraction or polarity at the level of the atoms.
2.2 Organic compounds
2.2.1 The compounds of our focus are those structures
that are organic in nature. Primarily it is the organic molecules that
are the basis of indoor contamination. We need to understand these
compounds so we know how to clean and purify the home.
2.2.2 Organic compounds are carbon based. Life
is determined by carbon based DNA and amino acid chains. Carbon is not
only found in "life," but a whole range of chemicals. A number of useful
organic compounds are made up of carbon, nitrogen, hydrogen, oxygen and
traces of other elements.
recognizable organic compound is based upon the carbon and hydrogen
combination, or hydrocarbons. Plastics, petroleum products and gasoline
tend to break down or decay faster than non-organic. The decaying
process means hydrogen and carbon molecules separate. For example, if
the plastic (organic) in milk bottle is left in the sun for a couple of
years, much of it will decay. Skin, hair, tissue (all organic) decays
The toxic VOC gases
in our homes such as formaldehydes and benzenes are
hydrocarbons. Airborne indoor dust particles, like dander, hair, dust
mite feces, etc. are based upon organic compounds generally associated
with the lipid group. And, of course, bacteria, molds and viruses
are based upon carbon.
2.2.3 Here is
the thread that runs through all indoor contaminates; those things that
pollute our homes are almost entirely based upon organic or carbon based
understanding, we now focus on the forces that will break down organic
and carbon based contaminate molecules. In short, a photochemical
process, initiated by short-wave ultraviolet can do
accept but don’t understand the damaging effects of x-ray and gamma ray
radiation. Why isn’t visible light as destructive on human cells or
bacteria as x-ray and short wave UV have been shown to be?
2.3.1 X-ray, gamma, ultraviolet, infrared and visible
light energy all fit in a category called "electromagnetic" energy. They
all have the same characteristic "lazy S" energy wave, as seen in Figure
#1, that travel at the speed of light. The light ray energy is called
photons that oscillate, resulting in wave
difference in each type of wave energy is the wavelength,
the distance across this wave. By definition, the shorter the
distance across the wave, the more powerful the wave will
be. The difference in the wavelength determines how the wave
affects its surroundings.
It is this
wavelength difference that allows short-wave x-ray to pass through
walls, while longer-wave visible light cannot pass though the same
material; short-wave ultraviolet and x-ray can destroy DNA in living
microorganisms and breakdown organic material while visible light will
Nanometers: Measuring Light Energy All light energy is measured on a
"nanometer" (nm) scale as outlined in Table #2. Nanometer means
one-billionth of a meter. The lower end of the scale has the shortest
wavelength, and the upper the longest. Cosmic, gamma, x-rays and "C"
band UV are all classified short-wave energy. Visible light is at middle
ground, at 400-700 NM on the scale. Infrared light is in the upper end
of the spectrum, running from about 800 to 1400 NM, and radio waves are
longer yet in the 1400 to 2200 NM range.
Spectrograph: Charting Light Energy in Nanometers
2.3.4 What is Ultraviolet
188.8.131.52 Ultraviolet light is toward the low
end of this scale, from about 100 to 400 NM, with three
categories, "A," "B" and "C." UV is beyond the range of visible light
and cannot be seen. We only see evidence of its presence.
called "C" band (100 – 280 NM) is known as UVC. Most C band radiation is
screened from the sun before reaching the earth by the production of
ozone in the upper atmosphere. Useful UVC is entirely manmade, found in
today’s low-pressure UVC lamps.
effective sterilizing range for UV is within the C bandwidth. This range
is called the germicidal bandwidth. The ideal germicidal curve is
considered 240 NM to 280 NM, with the most effective at 265 NM (Figure
184.108.40.206 With the initial
exposure, UVC has properties that alter the cells of living tissue,
particularly microbes. UVC radiation triggers the formation of peptide
bonds between certain amino acids in the microbe’s DNA molecules. This
renders bacteria, viruses and molds harmless by robbing them of the
ability to reproduce. If the germ cells are exposed for longer periods,
they start breaking down to the molecular level (carbon, oxygen,
hydrogen, nitrogen ions, etc.).
It has been determined that the optimal wavelength for
germicidal effectiveness is 265
Germicidal effectiveness is based upon UV intensity. Intensity is
measured in microwatts per square centimeter (µw/cm˛). The energy
required to destroy a microorganism has one more element, time. It is
microwatt-seconds per square centimeter (µw x
sec/cm˛), with "seconds" in the formula meaning the energy in seconds
(time) necessary to kill the microorganism. Table #4 is based upon an
energy output of µw-sec/cm˛ at 253.7 NM to destroy 90 percent of
the organisms at 1 meter:
Germicidal energy required to destroy common
Bacillus megaterium spores
Bacillus subtilis spores
2.5 Photochemical Process,
the Mechanics of Ultraviolet
are a number of reactions going on when UV irradiates germs and organic
compounds. As seen in the nanometer chart, UVC is near the x-ray group
and has similar characteristics, i.e., both have very short wavelength
energy. This short wave energy stimulates other secondary processes when
UV irradiates organic material.
photon is light ray energy. The science of UV is essentially the science
of photochemistry, or photon-chemistry.
Photochemistry is defined as a chemical reaction or
change in a material induced by the radiation of light energy.
Sunburn is a photochemical process that alters the chemistry of the
skin, causing a breakdown.
2.5.2 The photochemical process is essentially
a photoionization process where electrons of a molecule are
ejected or changed by the irradiation of light energy, leaving an
incomplete molecule (ion). With an absence of an electron, a
compound becomes unstable and "falls apart."
first rule of this photo energy process is that
each type of compound has a sensitivity level to photon
energy; there is a given wavelength of light energy at which each type
of material will react. It is at this given wavelength that electrons
are stripped (or altered) from the target molecule, breaking bonds and
causing a chemical alteration.
2.5.4 The second rule in this
degradation process is the higher the frequency of a wave, the
shorter the wavelength, the more energy a wave has in breaking
chemical bonds of a material.
All organic material
is photodegradable, at some point within the 100 to 320 NM bandwidths.
And within this range, each compound has a characteristic sensitivity
where peak chemical alteration will occur.
2.6 Ultraviolet and
the 100 – 280 NM bandwidth not only breaks down electron bonding
(primary process) of an organic molecule, but also instigates an
oxidation process (secondary process).
first example is ozone. The stable oxygen (O2) molecule
readily absorbs ultraviolet light at 184 nanometers (NM). This
absorption of ultraviolet light in the atmosphere breaks the molecular
bond between a two-oxygen molecule (O2), resulting in an
O1 free radical (atomic oxygen). A single atom
(O1) of oxygen will immediately search for a stable molecular
combination, often O2. This new combination forms ozone
(O3), which is highly corrosive.
Picture 2B: The
In 1972, it was
discovered that Ultraviolet (UV) could clean surfaces of organic
contamination. The ideal nanometer location of absorption of ozone and
organic molecules were identified. Ultraviolet light has a range of 100
NM to 400 NM Thus, UV light contains the optimal spectral absorption
line (184.9 NM) for O2 and can be a highly effective method
for ozone production.
It was also learned
that the combination of ozone and UV could clean surfaces up to 2,000
times quicker than ozone alone, as shown in the next table.
However, it has also been determined that ozone is very corrosive
on metal parts and can be damaging to HVAC systems when combined with
UVC. Thus any UV which produces ozone (184 NM), may prove
destructive to aluminum coil fins and copper
|"Black light" (>300nm)
O3 (produced by ozone
generator), no UV
UV @ 253.7 NM, no O3
UV @ 253.7 NM, + O3
(produced by ozone generator)
UV 253.7 NM & 184.9 NM + O3
(produced by O2 absorption of 184.9 NM wavelength, plus presence of
intermediate atomic oxygen)
Thus, there are several reasons for not using ozone in a central airflow
system: (a) ozone is not only corrosive to the metals in the airflow
system, but (b) ozone is also very corrosive to the lung tissue as we
breathe it. The EPA and American lung association are now strongly
against the use of ozone indoors.
To prevent the
production of ozone by UV in a HVAC system, all UV rays below 200 NM
need to be blocked. This can be done with a titanium-dioxide material in
the UV lamp glass.
2.7 Ultraviolet Producing Hydroperoxide and Hydroxyl
organic materials that concern us have a strong absorption band between
200 NM and 320 NM Thus UVC at 254 NM (without ozone formation) can clean
organic contaminants from a surface material. The reason is that most
organic molecules are vulnerable to this short wave UV irradiation. This
is because the continued existence of such molecules is dependent on
molecular weights; and that weight is altered when short-wave UV
irradiation reduces the number of electrons orbiting an organic
molecule, causing decay of the material.
ozone, what is not well understood is that there are two other naturally
occurring processes that accelerate the break down of organic materials
on the A/C coil. These two processes are highly effective oxidizing
agents on organic materials, but have little effect on the metals in the
organic particles are primarily byproducts of human, animal, insect and
microbial output from the indoor environment (dead skin, hair, paint
flakes, insect feces, carpet fibers, etc.). These particles collect on
coil fins in two ways: (a) mold growth in the damp coil
environment produces a sticky enzyme material for collection of airborne
organic material for food (this forms an activated crusty surface on the
fins); and (b) the close fitting coil fins collect airborne organic
particles much like a filter. s
collection and growth on the A/C coil results in decreasing coil
efficiency and increased energy costs.
2.7.2 Hydroperoxide development: This first
oxidizing process (within 200 – 320 NM) is the result of electron
ejection by UV irradiation of organic materials, giving rise to free
radical (hydrogen ion) development. The radicals react with ordinary
atmospheric oxygen (O˛), forming hydroperoxide (H˛O˛) ions. The
hydroperoxide process activates a chain reaction with the organic
material from the continual UV destruction of the hydroperoxide,
triggering further oxidation. This oxidation process primarily operates
on organic compounds and not metals.
2.7.3 Hydroxyl Radicals: Another key development at
an operational coil is the generation of water through condensation on
the fins. Studies by Mattex (1974) showed that the presence of water
with UV light energy enhances the decaying process of organic molecules.
It is the result of hydroxyl secondary oxidation, and it too is
primarily targeted toward organic molecules.
The presence of
water droplets being exposed to UV (200 to 320 nm) in the coil area
breaks down water molecules (H˛O), resulting in the formation of
hydroxyl (HO) radicals. These radical ions are stable but a very potent
one-electron oxidant. The reason hydroxyl ions are so destructive to
organic molecules is the ions steal hydrogen molecules from the organic
materials, leaving decayed carbon ions.
The theft of
hydrogen from organic molecules by hydroxyl radicals forms even stronger
OH bonds, with even higher oxidation, as the result of the water at the
coil. The process turns into a chain reaction…the breakdown and
formation of new HO radicals’ results in continual decay of the organic
2.8 Reaction of organic materials exposed to
cleaning mechanism of UV is a photochemical process. Since the ideal
range is 200 to 320 nm for organic degradation, ozone production, at 184
nm, is not needed nor should be used due to the destructive nature of
ozone on metals.
2.8.1 On the
other hand, hydroxyl radicals tend to target organic materials for
oxidation and not metals. These radicals absorb hydrogen out of organic
compounds. Because of this, hydroxyl is ideal for cleaning organic
growth at the A/C coil without the corrosive effects of ozone on the
aluminum and copper coil.
2.8.2 A damp
coil is perhaps the best environment to experience the full effects of
UV. It is in this ideal area that UV photon breaks down the collected
organic material, setting off a chain reaction of hydroxyl and
hydroperoxide formation, which further destroys organic materials.
This means that UV
light in C bandwidth effectively cleans the coil of organic particle
collection and destroys any growth of germs and mold accumulating at the
coil. Once the coil is cleansed, "…a clean surface under UV radiation
maintains surface cleanliness indefinitely."
irradiation within the system degrades airborne microorganisms and other
organic contaminates (particles and toxic VOC gases) circulating within
the air stream of the home, with the same photochemical reaction.
Dust: House dust is made up of a mixture of organic
materials and molecules: from paint flakes to pet hair, from insect
parts to fecal materials. Each house is different, but there is no
question that the basis of all house dust is organic in nature.
organic dust and debris floating in the air starts to break down when
exposed to high levels of UV energy.
Simply stated, the
exposure of an outside energy force can break the molecular bonds of
many common contaminants found in indoor air today, thus, resulting in a
cleansing effect which can improve the quality of life.
Down VOC’s Smoke & Odors: Smoke, fumes, and vapors
are some combination of organic compounds in a gaseous state. They can
be broken down rather quickly to the elementary level with the right UV
intensity and energy source.
Odor is based upon
what the human nose can smell. This means that as compounds gasify, they
give off some mixture of molecules that sensitize the nose. Odors come
from compounds floating in the air. Applying sufficient energy will
change the compounds’ molecular structure, thus effectively reducing or
eliminating the odor.
Application of New Ultraviolet Technology
current ClarionHEALTH ultraviolet (UV) products are
engineered to function within the central circulating air system of a
typical home or business establishment. This means the UV device is
inserted into the air stream.
ClarionHEALTH‘S HEALTHstar UV unit is the
only device in the marketplace capable, with sufficient intensity, to
function in very unstable conditions of high wind speeds and
temperatures near 45° F found in indoor air circulating systems. Other
devices will lose up to 80% of the intensity in these severe
conditions…not HEALTHstar. It is so powerful that it can
sterilize this nest of growth and the circulating air at the same time.
Designed UV Lamp
HEALTHstar’s UV lamp has been submitted for patent protection. It is an
unusual lamp. In an environment where hazardous (cold temperatures and
high wind speeds) conditions pose a problem for ultraviolet intensity, a
special UV lamp has to be used. That lamp is the HEALTHstar’s
lamp. It thrives in very cold temperatures. How?
Picture 2F: U bend Lamp
2.10 Hot Cathode Method
Cathode " method of generating ultraviolet refers to elements of the
lamp getting hot and igniting the internal gases. Hot cathode lamps
generally use tungsten filaments at each end of the tube. These
filaments are preheated by employing a glow switch starter and choke or
an electronic trigger. This makes the "Hot Cathode" UV lamps similar to
standard preheat fluorescent lamps used for lighting our homes and
filaments tend to govern the life of the UV lamp. They burnout.
Frequent starts will cause the filaments at each end of the lamps
to deteriorate even faster. In the end, preheat filaments shorten
the effective life of the hot cathode UV lamps because they age with
filament problem, the life of the lamp is also dependent upon the
effective ultraviolet transmission of the glass and the life
"mercury-vapor" gases or plasma. And this becomes a problem for this
type of lamp. Operating the filament lamp in refrigerator like
temperatures (around the A/C coil) can result in "excessive bulb
blackening and rapid depreciation in ultraviolet output."
2.10.2 The hot cathode lamp has difficulty
functioning at temperatures below 70° F. At 50° F filament lamps
generally lose up to 90% of the UV intensity. The reason for this is
there is no stabilizing current for the plasma across the lamp between
the two filaments.
The filaments heat
the two ends to create an ionized ball around the filament. Ionization
means knocking-off electrons from the molecule (without the electron it
is called an ion). The lost electron bounces across to hit another
molecule, knocking off another electron, leaving another ion. The chain
reaction continues across the lamp until the whole mass is ionized. The
heated ions result in plasma, which irradiates light energy in the form
In a cold cathode
lamp, the chain reaction of electrons knocking off other molecule
elections requires a certain temperature level to maintain the reaction
and keep the molecules excited. That temperature should be between 80° F
and 110° F.
But if the coil
cools the temperature around the hot cathode lamp to 50°, there is
insufficient heat to maintain the process and the reaction collapses.
There is nothing between the two ends to maintain the heat at colder
temperatures. Therefore, the UV intensity drops by 90 percent.
2.11 Cold Cathode Method
cold cathode lamp means it starts from a cold start - no
preheating. This type of lamp uses cylindrical electrodes and is
started instantly by means of a high voltage "spike." This is often
referred to as the "striking" voltage. Since the electrodes
seldom wear out, the cold cathode lamp normally has a much longer
life compared to the hot cathode, filament lamp.
the life of the cold method is not dependent upon electrodes, it then
comes down to the transmission of ultraviolet through the glass or the
life the plasma. But here again the electrode lamp has an advantage -
this lamp may be operated in very cold temperatures without excessive
"blackening" of the glass, thus little or no loss of UV output. The high
voltage assures a fast, instant start at even freezing
There are two
electrodes at opposite ends in the cold cathode lamp: one is a positive
post the other is the negative. By continually sending a high voltage,
low amperage charge between the two posts, one has a stabilizing heat
source that will maintain the ionization process even in extremely cold
or hot temperatures.
Temperature and Air Speed Factors
temperature and air rushing past the UV lamp can affect both the
operation and life of any UV lamp, particularly if the lamp is the hot
method. As indicated above, both the plasma collapses and the glass can
solarize or blacken excessively when using the hot cathode tube
in cold temperatures. This blocks UV irradiation, resulting in
depreciation in ultraviolet output. Further, lower temperatures cause
rapid deterioration of UV output when accompanied by higher air velocity
(wind speed) found in air conditioning systems.
fluctuations in temperatures and air velocities cause an "aging" process
in hot cathode UV lamps. These fluctuations can impact the lamp, much
like frequent starting. The chilling of the internal UV gases causes
rapid changes in the electrical characteristics of the filaments. This
ages the filaments much faster.
As was discussed in
the previous section, the ideal temperature for the most effective UV
output is about 80° F to 110° F, with a wind speed of less than 200 fpm.
Any variance from these conditions can cause a deterioration of the
mercury vapor and faster aging of the lamp.