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How an Ionizer Works
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Negative ions can be be produced by
copying any of the ways that nature uses - ultra violet (lamps),
radioactive sources etc. Indeed a bathroom shower provides a plentiful
supply! But it most cases it is
either too dangerous, too expensive or just impractical. For this
reason
most manufacturers use the method called "corona discharge" which is
similar to lightning.A high voltage (but at extremely limited current,
for safety) is applied to one or more needles. Electricity is a flow of
individual
electrons. And these electrons, supplied by the internal circuit, are
pushed down the needle towards the point. The nearer they get to the
point,
the closer they become forced together. Electrons naturally repell each
other, so as they reach the tip, the pressure becomes too much and they
"jump" off, onto the nearest air molecule, turning it into an ion.By
adjusting
the voltage level, the needle profile and the various materials used,
this
process can be made very efficient.Negative ions again repell each
other,
so they are driven from the needles as a gentle breeze, forming a dense
"cloud" in front of the ionizer, which disperses in all directions into
the
room.
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Air
ions have two qualities:
- They are beneficial to health by their inhalation
and absorbtion.
- They are very efficient air cleaners, particularly
of the smaller sized, more hazardous particles.
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The ions leaving the ionizer are
small, high velocity ones. These are found to be most beneficial to
health. If they collide with
particles of smoke or pollution near the ionizer, they pass on their
"static"
charge. This particle is then strongly attracted to the nearest
"earthed"
surface. (which could be a wall or the shelf on which the ionizer is
placed
- so make sure it is washable!) Out into the room the ions naturally
begin
to slow down. As they drift, pollutants such as dust, pollen, cigarette
smoke and even vapourised substances like aerosol propellants and car
fumes
are attracted to and cluster around the ions. This has the effect of
making the ion grow in size. There comes a point where it is too heavy
to be carried in the air, so it falls to the ground.The ability of an
ionizer to remove very fine particles from the air makes it extremely
valuable for health. Recent studies indicate that the smaller the
particle, the harder it is for our immune systems to cope with. So
ionizers have a "double action"
effect. They excel at removing microscopic particles - the most harmful
- and at the same time they restore a "vitality" to the air - which our
bodies appear to need for their everyday functioning. The quoted range
of
an ionizer is usually the distance at which it can maintain a certain
concentration
of ions. (the standard figure is 1000 ions per cc of air - said to be
the
lower threshold level for health purposes). However most ionizers will
have
a cleaning effect over a greater distance. A very important
point to be aware of: A badly designed ionizer may produce
ozone, and
with it nitrous oxide. These are toxic substances and can cause
respiratory
difficulties and stinging eyes (often the very thing they were
purchased
to cure). The WHO (World Health Authority) guidelines, say that the
maximum
acceptable level of ozone is 0.1ppm (parts per million). So when
purchasing,
make sure it is from a reputable company. (We have tested some cheap
models
in the past, and they really are unpleasant to use).
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air
ionizers