Indoor Air
Quality:
Indoor air quality is a general term describing the condition
of air inside buildings. Such air quality is influenced by the
temperature and humidity of the air, and the level of carbon dioxide
that is produced by occupants. Air quality may be influenced adversely
by the presence of toxic air contaminants (particles, gases, vapors,
and fumes) in concentrations sufficient to cause health problems,
and by agents that have specific odours that can be offensive
or irritating. The most common indoor contaminants are the volatile
organic compounds (VOC's) outgassed from interior furnishings.
Microbiological contaminants (namely bacteria, mould,
mildew and fungi) run a close second.
While air quality
is often the major concern for a comfortable indoor environment,
that environment may also be influenced adversely by heating or
cooling problems, as well as issues of noise, lighting, and other
factors.
Sick
Building Syndrome:
This syndrome is diagnosed when many building occupants complain
of nonspecific problems such as headache, fatigue, dry skin, and
eye, nose and throat irritation that they relate to being in the
building. In the US there are many litigation
cases relating to indoor air quality.
IAQ Sources:
There are
many sources of indoor air pollution in any building. These include
combustion sources such as oil, gas, kerosene, coal, wood, and
tobacco products; building materials and furnishings as diverse
as deteriorated, asbestos-containing insulation, wet or damp carpet,
and cabinetry or furniture made of certain pressed wood products;
products for household cleaning and maintenance, personal care,
or hobbies; central heating and cooling systems and
humidification devices; pesticides, and outdoor
air pollution.
Controlling
IAQ Problems:
Ventilation and filtration certainly provide a means of combating
these contaminants by diluting their concentrations within a building.
However, the basic long-term IAQ strategy for any building should
ultimately be contaminant source control.
By keeping HVAC
duct work clean and dry, we can significantly reduce the potential
for microbial contamination within a building.
The cooling coil
of the air conditioning system provide the necessary conditions
for mould, fungi and bacterial growth.
All air circulated by the air conditioning system passes throught
the cooling coil.
By-products of the
bacterial, mould and fungi that colonise the air handling system
of modern buildings create endotoxins, mycotoxins and a range
of toxic allergenic organic fragments collectively known as macromolecular
organic dust (MOD). Conventional air filters fail to capture MOD.
Some symptoms of
macromeolecular organic dust are:
- skin irritations
- sore throat
- fatigue
- respiratory complaints
- lung infections
- nausea
- blocked sinuses
- headaches
- eye irritations
Coil
cleaning and sanitisation is the most effective method of
fungi and bacterial control within air handling systems.
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