United States
Environmental Protection
Agency
Air and Radiation
(ANR-445-W)
Research and
Development
April 1991
&ER2V Indoor Air Facts No. 4 (revised)
Sick Building Syndrome
INTRODUCTION
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 contami-
nants.
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:
D Building occupants complain of
symptoms associated with acute dis-
comfort, e.g., headache; eye, nose,
or throat irritation; dry cough; dry or
itchy skin; dizziness and nausea;
difficulty in concentrating; fatigue;
and sensitivity to odors.
Si The cause of the symptoms is not
known.
H Most of the complainants report
relief soon after leaving the building.
Indicators of BRI include:
H Building occupants complain of
symptoms such as cough; chest
tightness; fever, chills; and muscle
aches.
H The symptoms can be clinically
defined and have clearly identifiable
causes.
ED Complainants may require
prolonged recovery times after
leaving the building.
It is important to note that com-
plaints may result from other causes.
These may include an illness con-
tracted outside the building, acute
sensitivity (e.g., allergies), job-
related stress or dissatisfaction, and
other psychosocial factors. Never-
theless, studies show that symptoms
may be caused or exacerbated by
indoor air quality problems.
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Causes of Sick
Building Syndrome
he following have been cited
causes of or contributing factors
to sick building syndrome:
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, venti-
lating, and air conditioning
(HVAC) systems do not effec-
tively 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 con-
sumption, 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 Standard 62-1989).
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. Envi-
ronmental tobacco smoke con-
tributes 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 concentra-
tions, and some are known
carcinogens. Low to moderate
levels of multiple VOCs may also
produce acute reactions. Com-
bustion 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 nearby garage.
Biological contaminants:
Bacteria, molds, pollen, and
viruses are types of biological
contaminants. These contami-
nants may breed in stagnant water
that has accumulated in ducts,
humidifiers and drain pans, or
where water has collected on
ceiling tiles, carpeting, or insula-
tion. 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 re-
sponses such as mucous mem-
brane irritation and upper respira-
tory congestion. One indoor
bacterium, Legionella, has caused
both Legionnaire's Disease and
Pontiac Fever.
These elements may act in
combination, and may supplement
other complaints such as inad-
equate 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 prob-
lems; radon and asbestos cause
long-term diseases which occur
years after exposure, and are
therefore not considered to be
among the causes of sick build-
ings. This is not to say that the
latter are not serious health risks;
both should be included in any
comprehensive evaluation of a
building's IAQ.

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Building Investigation
Procedures
he 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 investigators) to discover
whether a complaint is actually
related to indoor air quality,
identify the cause of the com-
plaint, and determine the most
appropriate corrective actions.
An indoor air quality investiga-
tion procedure is best character-
ized as a cycle of information
gathering, hypothesis formation,
and hypothesis testing. It gener-
ally begins with a walkthrough
inspection of the problem area to
provide information about the four
basic factors that influence indoor
air quality:
Ei	the occupants
9	the HVAC system
9	possible pollutant pathways
O	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 upcom-
ing investigation; and, identifying
key individuals needed for infor-
mation 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 informa-
tion is obtained from the
walkthrough to construct a
hypothesis, or if initial tests fail
to reveal the problem, the investi-
gator should move on to collect
additional information to allow
formulation of additional hypoth-
eses. 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, C02, 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 occu-
pants continue to report health
complaints. Air sampling should
not be undertaken until consider-
able information on the factors
listed above has been collected,
and any sampling strategy should
be based on a comprehensive
understanding of how the build-
ing operates and the nature of the
complaints.
Solutions to Sick
BuiBding Syndrome
olutions to sick building
syndrome usually include combi-
nations 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; institu-
tion 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 pollut-
ants 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 pro-
vided. In many buildings, IAQ
can be improved by operating the
HVAC system to at least its design
standard, and to ASHRAE Stan-
dard 62-1989 if possible. When
there are strong pollutant sources,
local exhaust ventilation may be
appropriate to exhaust contami-
nated air directly from the build-
ing. Local exhaust ventilation is

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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, Ventila-
tion and Air Quality in Office
Buildings.)
Air cleaning can be a useful
adjunct to source control and
ventilation but has certain limita-
tions. Particle control devices
such as the typical furnace filter
are inexpensive but do not effec-
tively 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
T|
. M
United States
Environmental Protection
Agency (ANR-445-W)	"
Washington, DC 20460
Official Business
Penalty for Private Use $300
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, man-
agement, and maintenance person-
nel fully communicate and under-
stand 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.
Additional Information
For more information on topics
discussed in this Fact Sheet,
contact your state or local health
department, a non-profit agency
such as your local American Lung
Association, or the following:
\0
EcgHftS IV
'r	Ftttec&B Ageaey
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, ¦ 7?-'
National Institute for Occupational
Safety and Health
US Department of Health and Human
Services
4676 Columbia Parkway (Mail Drop R2)
Cincinnati, Ohio 45226
Public Relations Office
American Society of Heating, Refrigerat-
ing and Air-Conditioning Engineers
(ASHRAE)
1791 Tullie Circle, NE
Atlanta, Georgia 30329
Building Owners and Managers Associa-
tion International
1250 Eye Street, NW
Washington, DC 20005
Additional copies of this Fact Sheet
and others in the Indoor Air Series are
available from:
Public Information Center
US Environmental Protection Agency
Mail Code PM-211B
401 M Street, SW
Washington, DC 20460
First-Class Mail
Postage and Fees Paid
EPA
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