About Ozone
Ozone, or O3, is simply a
supercharged form of oxygen. We refer to the regular oxygen molecule that we
breathe as O2. Ozone is essentially O2 with an extra oxygen atom attached. Thus it
carries the O3 designation. Oxygen is regularly transformed into ozone
through forces such as lightning, and also ultra-violet (UV) light from the sun
striking the atmosphere of the earth. Nature has been creating O3 for millions of
years as a natural sanitizer. After a short period of time the O3 molecule is
designed to revert back to O2, regular oxygen, leaving no residue.
How
We Learn About It
The general public learns about ozone in two different ways. The first is the
protective ozone layer in the upper atmosphere that helps to reduce the amount
of ultra-violet light that strikes the earth, keeping our planet cooler. This
natural layer of O3 has gradually been depleted as a result of specific
pollutants such as aerosols and the older refrigerant gases.
This depletion is
sometimes referred to as “holes in the ozone layer” and is also a contributor
to skin cancer because too much UV light is now getting through. Steps have
been taken over the past 20 years by governments to reduce these pollutants and
there are hopeful signs that the ozone layer is making a slow comeback.
The second way we learn about O3 is the ground level ozone that develops in polluted cities.
Automobiles and industry pollute the air through exhaust emissions. When
ultra-violet (UV) light from the sun strikes these emissions, ozone is created
as one of the byproducts. Burning fossil fuel creates many other pollutants as
well, but ozone is the easy to measure and used as an overall indicator of the
pollution.
Since life began,
nature has created ozone by sunlight striking gases emitted from decaying
matter as a way to keep the earth fresh and clean. This is natures response to
pollution in the air. When the exhaust emissions are high, the O3 levels become
high as a response to the excessive pollutants that are emitted, especially
during summer. The ozone levels generally rise during the day in response to
the greater amount of sunshine and go back down at night as the O3 breaks down to O2. Ongoing exposure
to high levels of ozone at ground level can cause respiratory irritation,
especially when combined with particulate and the many other gases emitted from
burning fuels.
So there is concern
about not enough ozone in the upper atmosphere to protect us, as well as
elevated amounts at ground level in some cities that may cause irritation, both
in response to pollution. These two ozone issues are sometimes confused with
the main concern about burning fossil fuels, which is the release of chemicals
such as carbon dioxide. These pollutants are known as “greenhouse gases” that
trap heat coming off the earth and prevent it from escaping out into space.
Carbon dioxide is the main contributor to global warming, and very much on the
rise with no overall solution on the horizon.
The protective ozone
layer, on the other hand, appears to be returning as a result of coordinated
governmental actions. We can only hope that carbon levels will also come into
balance at some point in the future through conservation, technology and
cooperative governmental policies.
Without O3 and UV light
the earth would be a very smelly place with mold, mildew and viruses running
rampant. These natural sanitizers work together and are designed to keep the
outdoors fresh, clean and healthy. Normally, however, there is very little
ozone or UV light that gets into our indoor spaces where we spend nearly all of
our time. This is because the buildings where we live and work are designed to
shut out the natural elements. As a result, organic matter, moisture,
chemicals, microorganisms and other elements combine to generate unhealthy
indoor odors.
How It Is Used
Today, ozone is intentionally produced by man for a variety of purification
purposes. It is created by corona discharge as an electrical current is sent to
a dielectric material such as a ceramic plate, which splits the O2 molecule creating O3. Ozone can also be
created using a UV lamp that emits light in a certain spectrum in order to
split the O2 molecule. The main use of ozone is for cleaning and
disinfecting.
Ozone is injected in
nearly all bottled waters and is widely used in Europe for treating municipal
water supplies. It is a great alternative to chlorine for water purification,
although more expensive, because it leaves no taste or chemical residue. Sewage
and other waste are sometimes treated with ozone because it leaves no residue.
O3 is also used
for indoor air treatment but care must be taken so that is both safe and
effective.
The typical way O3 is used commercially for air treatment is by generating
ozone in an unoccupied space. For example, if a hotel wants to change a smoking
room to a non-smoking room, they often use a commercial ozone generator like
the OdorFree to pull odors out of the carpet, drapes, bedding, etc. Smoke and
fire damage restoration service companies also use O3 to remove
residual odors.
The FDA has approved O3 for treatment of air and water in food processing plants
because it reduces microorganism counts without impacting the flavor. Flood and
water damage restoration companies sometimes treat air with O3 at high levels
in unoccupied spaces to get rid of musty smells as well as mold and mildew.
Restaurants, bars, casinos, cruise ships, rental apartments, schools,
offices, time shares and many other locations are beginning to treat their
facilities with ozone during the off hours to get rid of odors and keep the
property smelling fresh and clean.
The reason that
ozone is able to reduce strong odors is because it goes after pollutants at the
source. O3 is a very active
form of oxygen that will naturally circulate throughout the room oxidizing
odors on surfaces. Ozone can also follow the same path that vapors took when
they entered soft materials and oxidize many of those embedded odors. It can
help accelerate the dissipation of chemicals from new carpet, furniture and
paint as well. There are numerous other applications.
Caution
The
level of O3 generated in a
particular setting on the dial will vary with humidity, altitude, household
contents, level of indoor pollutants and other factors. The average person is
able to smell ozone as the room level approaches 30 part per billion (ppb)
indoors. The FDA sets an upper level of 50 ppb in continuously occupied spaces
for sensitive persons such as the very young, the elderly and the sick. The EPA
has set a target level of 80 ppb for outside air in cities, but that level is
regularly exceeded.
The properties that
make ozone a powerful cleaner and disinfectant also create a concern for
long-term exposure. Excessive ozone concentrations can cause mucus membrane or
respiratory irritation. But in order to successfully eliminate heavy odors or
reduce microorganism growth, the levels may need to be elevated. Therefore, it
is best to use ozone for air treatment in unoccupied spaces. If O3 is detected
when entering a room, it is important to turn the ozone generator off, and
vacate the area until it dissipates. This usually takes about an hour.
An Ongoing Cycle
Ozone is an important factor in protecting the earth from too much sunlight
coming through the upper atmosphere, while also helping keep it fresh and clean
at ground level. In the upper atmosphere and at ground level O3 is created daily,
as it has for eons, and then reverts back to O2 again. This is called the oxygen-ozone
cycle. At ground level, O3 normally reverts back to O2 in about an hour after it has been created.
O3 naturally has a
clean, sanitizing smell somewhat similar to chlorine. The difference with ozone
is that the sanitizing smell quickly dissipates after the odors have been
eliminated, as the O3 reverts back to oxygen. The end result is that an area treated
with ozone becomes free of odors, as nature intended.
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