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Sick Building Syndrome (SBS)
The term "sick building syndrome" (SBS)
is used to describe situations in which building occupants experience acute health and
comfort effects that appear to be linked to time spent in a building, but no specific
illness or cause can be identified. The
complaints may be localized in a particular room or zone, or may be widespread throughout
the building. In contrast, the term "building related illness" (BRI) is
used when symptoms of diagnosable illness are identified and can be attributed directly
to airborne building contaminants.
A 1984 World Health Organization Committee report suggested that up to 30 percent of
new and remodeled buildings worldwide may be the subject of excessive complaints related
to indoor air quality (IAQ). Often this condition is temporary, but some buildings
have long-term problems. Frequently, problems result when a building is operated or
maintained in a manner that is inconsistent with its original design or prescribed
operating procedures. Sometimes indoor air problems are a result of poor building
design or occupant activities.
Indicators of SBS include:
- Building occupants complain of symptoms associated with acute discomfort,
- Irritated eyes
- Runny nose
- Nasal congestion
- Scratchy throat
- Difficulty in concentrating
- sensitivity to odors
If you have asthma, air pollutants and irritants may trigger more
frequent and severe attacks. If your symptoms disappear when you leave home
for several hours but recur once you return, something in the air could be
- The cause of the symptoms is not known.
- Most of the complainants report relief soon after leaving the building.
Indicators of BRI include:
- Building occupants complain of symptoms such as cough; chest tightness; fever, chills;
and muscle aches
- The symptoms can be clinically defined and have clearly identifiable causes.
- Complainants may require prolonged recovery times after leaving the building.
It is important to note that complaints may result from other causes. These may include
an illness contracted outside the building, acute sensitivity (e.g., allergies), job
related stress or dissatisfaction, and other psychosocial factors. Nevertheless, studies
show that symptoms may be caused or exacerbated by indoor air quality problems.
How Can I Know if a Health Reaction is Due to a Sick
There are two components to identifying a sick building. The first is that
the reactions or types of reactions are shared by several or many of the people
who also inhabit the building. The second is that the reactions are triggered
when in the building and are not triggered when not in the building.
Individuals, however, may have greater sensitivities to some stimuli than do
other people. For these individuals, something or things in the building may be
triggering a reaction, but the building may not be "sick." This is
often the case when a certain office or part of a building is rehabbed or
reconfigured and decorated. That particular area of the building may create
reactions in individuals, but the building itself is not problematic.
Causes of Sick Building Syndrome
The following have been cited causes of or contributing factors to sick building
Inadequate ventilation: In the early and mid 1900's,
building ventilation standards called for approximately 15 cubic feet per minute (cfm) of
outside air for each building occupant, primarily to dilute and remove body odors. As a
result of the 1973 oil embargo, however, national energy conservation measures called for
a reduction in the amount of outdoor air provided for ventilation to 5 cfm per occupant.
In many cases these reduced outdoor air ventilation rates were found to be inadequate to
maintain the health and comfort of building occupants. Inadequate ventilation, which may
also occur if heating, ventilating, and air conditioning (HVAC) systems do not effectively
distribute air to people in the building, is thought to be an important factor in SBS. In
an effort to achieve acceptable IAQ while minimizing energy consumption, the American
Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently revised
its ventilation standard to provide a minimum of 15 cfm of outdoor air per person (20
cfm/person in office spaces). Up to 60 cfm/person may be required in some spaces (such as
smoking lounges) depending on the activities that normally occur in that space (see ASHRAE
Chemical contaminants from indoor sources: Most indoor air
pollution comes from sources inside the building. For example, adhesives, carpeting,
upholstery, manufactured wood products, copy machines, pesticides, and cleaning agents may
emit volatile organic compounds (VOCs), including formaldehyde. Environmental tobacco
smoke contributes high levels of VOCs, other toxic compounds, and respirable particulate
matter. Research shows that some VOCs can cause chronic and acute health effects at high
concentrations, and some are known carcinogens. Low to moderate levels of multiple VOCs
may also produce acute reactions. Combustion products such as carbon monoxide, nitrogen
dioxide, as well as respirable particles, can come from unvented kerosene and gas space
heaters, woodstoves, fireplaces and gas stoves.
Chemical contaminants from outdoor sources: The outdoor
air that enters a building can be a source of indoor air pollution. For example,
pollutants from motor vehicle exhausts; plumbing vents, and building exhausts (e.g.,
bathrooms and kitchens) can enter the building through poorly located air intake vents,
windows, and other openings. In addition, combustion products can enter a building from a
- Home chemicals. Cleaning solutions can release toxic fumes. Never mix
chemical products, especially chlorine bleach, with ammonia cleaner. Follow
instructions for all home chemicals — including hobby materials such as
solder, spray paint and paint stripper. Use them only in a well-ventilated
area. Air out your home after the use of insecticides or pesticides.
- Redecorating hazards. Newly installed carpet and other materials, such
as paint, can give off irritating fumes. Before having carpet laid, ask the
installer to unroll the carpet and air it out in a well-ventilated area for as
long as possible. For both new carpet and fresh paint, open up your house and
run exhaust fans during the first few days. Asbestos- and
formaldehyde-containing building materials usually found in older homes also
are potential sources of indoor air pollution.
Biological contaminants: Bacteria, molds, pollen, and
viruses are types of biological contaminants. These contaminants may breed in stagnant
water that has accumulated in ducts, humidifiers and drain pans, or where water has
collected on ceiling tiles, carpeting, or insulation. Sometimes insects or bird droppings
can be a source of biological contaminants. Physical symptoms related to biological
contamination include cough, chest tightness, fever, chills, muscle aches, and allergic
responses such as mucous membrane irritation and upper respiratory congestion. One indoor
bacterium, Legionella, has caused both Legionnaire's Disease and Pontiac Fever. More
information about biological contaminants
Dust mites — microscopic insects found in household dust
— and their byproducts, along with mold, can cause severe allergy problems.
Damp conditions can aggravate the problem. To keep dust mites at bay, vacuum
and dust often. Put bedding in allergen-impermeable covers and wash bedding
weekly in hot water. Information about
dust mites and their control
These elements may act in combination, and may supplement other complaints such as
inadequate temperature, humidity, or lighting. Even after a building investigation,
however, the specific causes of the complaints may remain unknown.
|A Word About Radon and Asbestos...
SBS and BRI are associated with acute or immediate health problems; radon and asbestos
cause long-term diseases which occur years after exposure, and are therefore not
considered to be among the causes of sick buildings. This is not to say that the latter
are not serious health risks; both should be included in any comprehensive evaluation of a
Building Investigation Procedures
The goal of a building investigation is to identify and solve indoor air quality
complaints in a way that prevents them from recurring and which avoids the creation of
other problems. To achieve this goal, it is necessary for the investigator(s) to discover
whether a complaint is actually related to indoor air quality, identify the cause of the
complaint, and determine the most appropriate corrective actions.
An indoor air quality investigation procedure is best
characterized as a cycle of information gathering, hypothesis formation, and hypothesis
testing. It generally begins with a walkthrough inspection of the problem area to provide
information about the four basic factors that influence indoor air quality:
- the occupants
- the HVAC system
- possible pollutant pathways
- possible contaminant sources.
Preparation for a walkthrough should include documenting
easily obtainable information about the history of the building and of the complaints;
identifying known HVAC zones and complaint areas; notifying occupants of the upcoming
investigation; and, identifying key individuals needed for information and access. The
walkthrough itself entails visual inspection of critical building areas and consultation
with occupants and staff.
The initial walkthrough should allow the investigator to
develop some possible explanations for the complaint. At this point, the investigator may
have sufficient information to formulate a hypothesis, test the hypothesis, and see if the
problem is solved. If it is, steps should be taken to ensure that it does not recur.
However, if insufficient information is obtained from the walk through to construct a
hypothesis, or if initial tests fail to reveal the problem, the investigator should move
on to collect additional information to allow formulation of additional hypotheses. The
process of formulating hypotheses, testing them, and evaluating them continues until the
problem is solved.
Although air sampling for contaminants might seem to be the logical
response to occupant complaints, it seldom provides information about possible
causes. While certain basic measurements, e.g., temperature, relative humidity, CO2, and
air movement, can provide a useful "snapshot" of current building conditions,
sampling for specific pollutant concentrations is often not required to solve the problem
and can even be misleading. Contaminant concentration levels rarely exceed existing
standards and guidelines even when occupants continue to report health complaints. Air
sampling should not be undertaken until considerable information on the factors listed
above has been collected, and any sampling strategy should be based on a comprehensive
understanding of how the building operates and the nature of the complaints.
What Can I Do?
The best way to deal with potential reactions to a sick building, is to
understand the reasons a building may be "sick." The predominant
culprit in most buildings is the flow of air. Fresh air and air movement
patterns keep a building "flushed." As buildings become sealed or an
interior is redesigned and changes the air flow, air may not move as freely and
the contaminants can accumulate in the closed space. Poorly designed or
maintained ventilation systems (HVAC) can also create problems, especially in
situations where the pollutants can "buildup" over time due to poor
The second cause can be a synergistic or combination interaction among low
levels of specific pollutants. In these cases, when the specific pollutants are
identified, the contributing factors are removed or altered to minimize the
effect. For individuals, specific causes may be traced through
"histories" of other situations in which the individual has had
Other factors that can contribute to the symptoms associated with "sick
building syndrome" are some that can be relatively easily maintained. Too
low or too high a humidity level or changes in relative humidity in a building
can aggravate individuals. Too low humidity can increase dust and particulate
indoor pollution, and too high humidity can provide a breeding ground for molds
and fungi. Poor lighting can increase eye strain and result in symptoms similar
to "sick building syndrome." Extreme temperature fluctuations in a
building can serve to release VOCs and molds/fungi.
If you suspect a building of "making you sick," first track your
reactions. What types of reactions, what are the triggers for the reaction, and
do the reactions abate when you are not in the building? Next, examine the
building for things you can control. Can you open windows or doors to improve
air flow? Many types of adjustments that could alleviate sick building symptoms
require major structural changes in building infrastructure. So, as an
individual, you will have to find the things that you can control. Can you
minimize the temperature changes within the building? Are there individual
activities, such as the use of colognes or perfumes, soaps, shampoos,
deodorants, perfumes in detergents, and air fresheners that can be controlled by
individuals within the building? Finally, if you believe it is a building that
is sick, gather the evidence from multiple occupants of the building - and if
possible have all occupants meet with one or a few health care providers - and
contact the owner of the building and your local health department.
Solutions to Sick Building Syndrome
Solutions to sick building syndrome usually include combinations of the following:
Pollutant source removal or modification is an effective
approach to resolving an IAQ problem when sources are known and control is feasible.
Examples include routine maintenance of HVAC systems, e.g., periodic cleaning or
replacement of filters; replacement of water-stained ceiling tile and carpeting;
institution of smoking restrictions; venting contaminant source emissions to the outdoors;
storage and use of paints, adhesives, solvents, and pesticides in well ventilated areas,
and use of these pollutant sources during periods of non-occupancy; and allowing time for
building materials in new or remodeled areas to off-gas pollutants before occupancy.
Several of these options may be exercised at one time.
Increasing ventilation rates and air distribution often
can be a cost effective means of reducing indoor pollutant levels. HVAC systems should be
designed, at a minimum, to meet ventilation standards in local building codes; however,
many systems are not operated or maintained to ensure that these design ventilation rates
are provided. In many buildings, IAQ can be improved by operating the HVAC system to at
least its design standard, and to ASHRAE Standard 62-1989 if possible. When there are
strong pollutant sources, local exhaust ventilation may be appropriate to exhaust
contaminated air directly from the building. Local exhaust ventilation is particularly
recommended to remove pollutants that accumulate in specific areas such as rest rooms,
copy rooms, and printing facilities. (For a more detailed discussion of ventilation, read
Indoor Air Facts No. 3R, Ventilation
and Air Quality in Office Buildings.)
Air cleaning can be a useful adjunct to source control and
ventilation but has certain limitations. Particle control devices such as the typical
furnace filter are inexpensive but do not effectively capture small particles; high
performance air filters capture the smaller, respirable particles but are relatively
expensive to install and operate. Mechanical filters do not remove gaseous pollutants.
Some specific gaseous pollutants may be removed by adsorbent beds, but these devices can
be expensive and require frequent replacement of the adsorbent material. In sum, air
cleaners can be useful, but have limited application.
Education and communication are important elements in both
remedial and preventive indoor air quality management programs. When building occupants,
management, and maintenance personnel fully communicate and understand the causes and
consequences of IAQ problems, they can work more effectively together to prevent problems
from occurring, or to solve them if they do.
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