|
 |
|
|
Indoor Air Quality
Additional Indoor
Air Quality Information
Background of IAQ
Over the last thirty
years, Indoor Air Quality (IAQ) has emerged as a
 major issue for commercial and institutional
facilities such as office buildings and schools. This emergence has been attributed to a number of
contributing factors. Firstly, the energy crisis of
the early 1970’s resulted in a shift in how
buildings were constructed. In order to reduce
energy costs, buildings were constructed ‘tighter’,
consisting of windows that could not be opened, with
control of environmental conditions and outdoor air
ventilation dependant solely on mechanical
ventilation. These heating, ventilating and
air-conditioning (HVAC) systems were then operated
with a lower percentage of outdoor air to save on
heating and cooling costs. Such changes in building
construction and operation have resulted in an
increase in the potential for build-up of internally
generated air pollution.
In addition to new
construction methods came new construction materials
and furnishings. Many more products are now being
introduced into buildings that are composed of
 synthetic materials, plastics, compressed wood
products, glues, varnishes and paints. These
materials will “off-gas” volatile organic chemicals,
especially when they are brand new or first
installed. Office furnishings, supplies and
equipment such as printers, computers, and
photocopiers as well as combustion appliances also
found their way into buildings at a much greater
rate than previously. The presence of these new
furnishings, materials and equipment combined with
the greater use of cleaning agents and pesticides
creates an indoor environment that generates a
multitude of indoor air contaminants at a rate
greater than ever before. In addition, the increase
in outdoor air pollution over the years has made the
quality of air coming into the building poorer.
With all of the above
changes it is no wonder that IAQ has emerged as a
significant concern. What makes it even more of a
concern is that there appears to be an increasingly
greater percentage of individuals in the population
that have an increased sensitivity to airborne
contaminants. The number of children with asthma
has reportedly increased by 60% during the 1980s,
and poor IAQ has been known to trigger asthmatic
episodes.
Health Effects of
Poor IAQ
People spend about 90%
of their time indoors and air within homes and other
buildings can be more polluted than the outside air,
even in the largest and most industrialized cities. Therefore, it is no wonder that the quality of air
in indoor environments has become a health concern
to building occupants.
Health effects resulting
from poor IAQ are varied. It is common for people
working indoors to report one or more symptoms such
as dryness and irritation of the eyes, nose, throat
and skin, headache, fatigue, shortness of breath,
hypersensitivity and allergies, sinus congestion,
coughing and sneezing, dizziness, and nausea. Due
to the myriad of health complaints reported by
occupants of buildings with poor IAQ, certain groups
of symptoms are sometimes characterized into what
are now common terms. These terms include Sick
Building Syndrome (SBS), Building-Related Illness (BRI)
and Multiple Chemical Sensitivities (MCS).
The term Sick Building
Syndrome is used to describe cases in which
occupants experience adverse health effects that are
apparently
 linked to the time they spend in the
building. However, no specific illnesses or cause
can be identified. SBS is characterized by
non-specific symptoms such as headaches, fatigue,
irritation of eyes, nose and throat, dry mucous
membranes and skin, coughs, hoarseness of voice and
wheezing, nausea and dizziness. These symptoms are
generally noted after several hours of work and the
occupant reports feeling better after they have left
the building. These symptoms may also be caused by
other factors other than poor indoor air quality.
Some other factors that should be taken into account
include lighting, noise, ergonomic factors and
work-related stress.
Building-Related Illness
refers to less frequent (but often more serious)
cases of people becoming ill after being in a
specific building at a certain time. Often, the
number of people that exhibit illness in the
building are less than in cases of SBS. However,
for BRI there is a well-known cause and effect.
That is, there is usually a set of specific clinical
symptoms experienced by the people and a clear cause
can often be found upon investigation. Examples of
BRI include respiratory allergies (often caused by
agents such as moulds), humidifier fever, nosocomial
infections and sensory irritation when caused by
known agents. Overexposure to specific chemical
contaminants such as carbon monoxide, formaldehyde
and pesticides can also cause BRI. Legionnaires
disease is an example of BRI caused by bacteria that
can contaminate a building’s air conditioning
system.
Multiple Chemical
Sensitivity is characterized by reaction to a
contaminant that causes health symptoms (such as
allergies, rashes and seizures) that can often be
severe. Although the etiology of MCS is not well
understood, it is believed that sensitivity to a
specific chemical or group of chemicals develops
from previous acute exposure or chronic low-level
exposure to the chemical(s). After sensitivity
develops, only very low concentrations of the
contaminant (that may not be measurable) are
necessary to elicit a negative response.
In
 addition to the
multitude of chemical and biological contaminants
that are implicated in poor IAQ, thermal comfort can
also result in complaints from building occupants.
Maintaining comfortable thermal and moisture
conditions generally improves occupant perception of
air quality. Good thermal comfort can be achieved
only when the air temperature, humidity, and air
movement are within the specified range often
referred to as the “comfort zone”. An office that
is too warm makes its occupants feel tired. On the
other hand, one that is too cold causes the
occupants’ attention to drift, making them restless
and distracted. Maintaining constant thermal
conditions in offices is important. Even minor
deviations in comfort may be stressful and lead to
impaired performance and safety.
The Benefits of Good
IAQ
As the public recognizes
the importance of healthy, comfortable and
productive indoor environments, its awareness and
demand for good IAQ increases. Increased public
recognition has resulted in IAQ emerging as a major
concern for building owners and facility managers,
as they need to keep building occupants happy and
productive. Good indoor air quality contributes to
a favourable learning or working environment,
increased productivity, and a sense of comfort,
health, and well-being for all building occupants.
Good indoor air quality makes good sense, and not
just from the perspective of building occupants.
Good IAQ does not have to compete with other
building management priorities; in fact, it can
enhance some and can also result in cost savings.
The major forms of these savings are efficiency and
productivity improvements, cost reduction in
operation and maintenance, and reduced incidence of
property damage.
One of the strongest
arguments for improving IAQ is that
 building tenants
and office workers believe IAQ and thermal comfort
are among the most important components to job
satisfaction. This evidence is brought to light by
several studies. One such study conducted by the
Building Owners and Managers Association (BOMA)
titled “What Office Tenants Want: BOMA/ULI Office
Tenant Survey Report” analyzed 1800 office
tenant surveys in 126 metropolitan areas. This
study found that 95% of respondents ranked
comfortable air temperature and 94% ranked indoor
air quality as among the “most important” tenant
comfort features. The study also found that the
number one reason tenants move out is problems with
keeping the indoor temperature comfortable.
Poor IAQ can lead to a
reduction in worker productivity. Occupants feeling
fatigued or bothered by eye irritation, etc. will
not be as productive, and more severe health effects
will result in lost time due to sick days.
Productivity lost due to poor indoor air quality is
difficult to measure. However, several studies have
attempted to determine the impact of poor IAQ. A
U.S. survey of 94 state government office buildings
attributes an average productivity loss of 14
minutes per day or 3% due to poor indoor air
quality. To put a numerical value to this, the
Occupational Safety & Health Administration (OSHA)
multiplied the average employee payroll by 3%,
resulting in an estimated annual productivity loss
of $15 billion across the U.S.
In addition to costs
associated with decreased productivity, poor indoor
air quality can also lead to increased costs due to
property damage, increased maintenance and cleaning
costs. High concentrations of contaminants can have
adverse effects on materials and equipment. Damages
may include corrosion of electronic components and
electrical current leakage, which may eventually
result in equipment malfunction. Materials and
equipment damage by indoor air pollutants include
maintenance, repair, and/or replacement costs
resulting from soiling or deterioration of
material’s appearance, or reduced service life for
corroded or degraded appliances, furnishings, and
equipment.
Results of hundreds of
studies and reports have demonstrated a significant
and causal correlation between improving the indoor
environment and gains in productivity and health.
An analysis of a large number of studies tried to
 quantify the potential health and productivity
benefits from providing good indoor environmental
conditions. Improving air quality not only leads to
significant reductions in illness but it also has a
direct positive impact on worker productivity. The
potential direct increase in office workers’
performance was estimated to range between 0.5% and
5%. In addition, other savings can be realized
through a reduction in maintenance costs. One study
found that by reducing the frequency of complaints,
a potential 20% savings of labour costs associated
with HVAC operation and maintenance was possible.
Therefore, providing good IAQ makes good sense from
all perspectives.
|
|
|
Copyright
© 2004, Safetech Environmental Ltd.
All rights reserved. |
|
Webdesign
by
Cyber52.com |
|
|
