- Sick building syndrome (SBS) refers to situations where building occupants experience acute health effects and discomfort that seem linked to time spent in the building, but no specific illness or cause can be identified. Symptoms may include headaches, eye and throat irritation, dizziness, and difficulty concentrating. - SBS can be caused by inadequate ventilation, volatile organic compounds from materials and equipment, combustion products, outdoor pollutants entering the building, and biological contaminants from water sources. - Effects of SBS include vague symptoms that cannot be objectively measured but improve when leaving the building. This costs work time and reduces productivity and economic output. Proper building investigation aims to identify and prevent the recurrence of indoor air quality

1. Indian Journal of Air Pollution Control Vol. V No. II September 2005 pp 46-53
Sick Building Syndrome
Neha Mukhi* and Mukesh Khare**
*Environmental Engineering Group, Delhi College of Engineering
Bawana Road, Delhi –110042, Email: nehamukhi@hotmail.com
** Corresponding Author: Professor, Department of Civil Engineering
Indian Institute of Technology Delhi, IIT, Hauz Khas,
New Delhi –110016, Email: mukeshk@civil.iitd.ac.in
Abstract
Sick building syndrome may be defined as a phenomenon that occurs in a building in which a part of the occupants
experience varying degrees of low levels of sickness or discomfort which are non-specific in nature and are dominated
by sensory reactions. In this paper are discussed the causes of sick building syndrome and the symptoms produced. The
paper also throws light on investigational procedures and possible remedial and preventive measures.
Keywords: Sick building syndrome, ventilation, investigational procedures
Introduction
Building, by definition is a structure that is built for human habitation. From the times, the buildings have
been built, humans have used them as a place to sleep, eat, and live. A building may vary from a tent to a
sky-scrapper. Humans focused on the building as a place to live and work, while science brought the issue
of sick building syndrome (SBS). Wordsworth Encyclopedia defines SBS as “a malaise diagnosed among
office workers and thought to be caused by such pollutants as formaldehyde (from furniture and insulating
materials), benzene (from paint) and other chemicals concentrated in air conditioned buildings. Symptoms
include headache, sore throat, tiredness, colds and flu.” However, this is a narrow definition. The term SBS
is old and broad. It does not apply only to office buildings, but it also applies to residential buildings. Mold
is one of the leading causes of SBS, and thus it is imperative to control the mold growth in the building in
order to prevent SBS for the well being of humans as well as the building itself. Every convenience comes
with possible backfiring. Indoor air can also work as a double-edged sword. Studies show that the optimal
relative humidity for human immunity system and comfort is at 45~65%, but at this level of humidity, the
mold, which is also a living organism, can have the benefit of growth as well. Thus it is for science and
building engineering to control humidity to minimize mold growth while remaining at a comfortable level of
humidity for human beings.
SBS and Building Related Illness
Over the years, construction techniques have significantly improved in order to make structures longer
lasting and less problematic. However, not every situation can be predicted and sometimes events occur that
lead to ‘Problem Buildings’. Problem buildings can be classified either as having occupants who experience
symptoms characterized as SBS or “Building Related Illness (BRI)” or both. The term SBS is used to
describe situations in which building occupants experience acute health and comfort related effects that
appear to be linked to the time spent in the building, however specific illness or cause cannot be identified.
The complaints may be localized in a particular room or zone, or may be widespread throughout the
building. In contrast, the term BRI is used when symptoms of diagnosable illness are identified and can be
attributed directly to airborne building contaminants (Lane et al, 1989). An important difference between
situations classified as SBS or BRI is that the specific SBS contaminant(s) need not be identified i.e., SBS
symptoms involved are sub clinical and they do not indicate the existence of any clinical disease (Wyson,
1992), and complaints often can be resolved by increasing system ventilation, by discussion with occupants
regarding their control of contaminant sources, and by improved system maintenance. On the other hand, the
cause of BRI incident must be determined usually before a solution can be implemented.
Indicators of SBS and BRI
Indicators of SBS include:

2.  Building occupants complain of symptoms associated with acute discomfort, e.g., headache, eye,
nose, or throat irritation; dry cough; dry or itchy skin; dizziness and nausea; difficulty in
concentrating; fatigue; and sensitivity to odours.
 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 also 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.
Causes of SBS
Inadequate ventilation is thought to be an important factor in SBS. It may occur if heating, ventilation, and
air conditioning (HVAC) systems do not effectively distribute air to people in the building. In an effort to
achieve acceptable IAQ while minimizing energy consumption, the American Society of Heating,
Refrigeration and Air-Conditioning Engineers (ASHRAE) revised its ventilation standard to provide a
minimum of 15 cfm of outdoor air per person, when 20 cfm/person are recommended in office spaces, and
up to 60 cfm/person may be required in some spaces such as smoking lounges (ASHRAE Standard 62-
1989).
Chemical contaminants from in-door sources e.g. adhesives, carpeting, upholstery, manufactured
wood products, copy machines, pesticides, and cleaning agents, may emit volatile organic compounds
(VOCs) including formaldehyde. 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. Environmental tobacco smoke contributes high levels of VOCs, other toxic compounds, and
respirable particulate matter. Research shows (Yeung et al, 1991) that some VOCs are known carcinogens
and can cause chronic and acute health effects at high concentrations. Low to moderate levels of multiple
VOCs may also produce acute reactions.
Chemical contaminants from outdoor sources e.g. 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 e.g. bacteria, molds, pollen, and viruses may breed in stagnant water that has
accumulated in ducts, humidifiers and drain pipes, or where water has got collected on ceiling tiles,
carpeting, or insulation. 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. These elements may act in combination, and may supplement other complaints such
as inadequate temperature, humidity, or lighting.
Psychological factors like perception of thermal, audio and visual environment related to sick
buildings have been regarded by some as mainly psychogenic in origin. Physical stressors, like air pollution
at low concentrations, may have a diffused and non-specific psychological effect (Berglund et al, 1984). For
example, an increasing number of occupants may experience anxiety and symptoms of stress independently
of one another, and when a new stimulus is introduced, like a noxious odour, another process may be
triggered leading to an epidemic with overt symptoms. SBS may also be partly a result of a changed
sensitivity in the population exposed (Berglund et al, 1986).

3. Effects of SBS
Cases of SBS report vague symptoms that cannot be objectively measured, and sufferers usually show no
clinical signs of illness. These symptoms are linked to building occupancy because they get better on leaving
the building. IAQ surveys of sick buildings often fail to find pollution problems even though complaints are
chronic and symptom prevalence among occupants is high with up to 80% of workers reporting at least the
same symptom (Wilson and Hedge, 1987). The various types of medical syndromes associated with
buildings are given in Table 1.
Table 1: Medical Syndromes Associated With Buildings (World Health Organization, 1983; Wilson
and Hedge, 1987)
Syndrome Symptoms
Sick building syndrome
 type 1
Lethargy and tiredness
Headache
Dry blocked nose
Sore dry eyes
Sore throat
Dry skin and/or skin rashes
Sick building syndrome
 type 2
Watering/itchy eyes and runny nose
i.e., symptoms of an allergy such as hay
fever
Humidifier fever
Flu-like symptoms
Generalized malaise
Aches and pains
Cough
Lethargy
Headache
Allergic reaction in sensitive individuals Chest tightness
Difficulty in breathing
Fever
Headache
Occupational asthma Wheeze
Chest tightness
Difficulty in breathing
In industrial and organizational settings negative effects of SBS become responsible for lost working
days, low efficiency and poor health, and hence low productivity in occupational environments, resulting in
higher economic cost of SBS than that attributed to normal lost time and health care. It has been observed
that improved indoor air quality can result in higher productivity and fewer lost working days (Rotton et al,
1996). Hence it is very essential to improve indoor air quality not only because of the health effects but also
because poor indoor air quality hampers human welfare socially and economically.
Building Investigation Procedures
The goal of building investigation is to identify and solve indoor air quality complaints in a way that
prevents them from recurring and also avoids the creation of other problems. To achieve this goal, it is
necessary for the investigator 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 (USEPA, www.epa.gov). It generally begins with a
walkthrough inspection of the problem area to provide information about four basic factors that influence
indoor air quality:
 Occupants
 HVAC system

4.  Possible pollutant pathways
 Possible contaminant source
Preparation for an inspection 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 inspection 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 inspection 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.
Alternatively, a survey consisting of two components as follows may be conducted. Objectives may be
summarized as follows to find out:
 The prevalence of characterized SBS as experienced by the occupants
 The relationship between the degree of comfort expressed by occupants and the corresponding
indoor environmental conditions and comparison with various widely accepted standards.
 The relationship between prevalence of symptoms, degree of comfort experienced by occupants and
indoor environmental conditions.
Components of the survey are subjective assessment and objective measurement (Yeung et al, 1991).
To obtain subjective feeling, questionnaires (Raw et al, 1996) may be distributed to the occupants (see
sample questionnaire in appendix (Katiyar, 2002). Details about low level symptoms such as dryness and
irritation of eye, nose, throat, skin, headache, lethargy, dizziness etc. experienced by the occupants can be
assessed. Objective measurements should be carried out (Yeung et al., 1991) at the same time as subjective
assessment to find out the environmental conditions and to determine the possible relationship between these
variables. Environment parameters to be measured may include:
Table 2: Environmental Parameters to be measured as a part of the building investigational
procedures.
Physical aspects Chemical aspects Biological aspects
 Air temperature (D.B., W.B)
 Ventilation measurement
 Mean radiant temperature
 Noise level
 Illuminance level
 Respirable dust particles
 NOx
 NO
 SO2
 CO
 CO2
 Formaldehyde
 Infectious agents (bacteria, virus etc.)
 Pollen
Questionnaires usually collect data on occupants' perceptions of environmental conditions and
health over extended periods of time, such as one month, 3 months, 1 year, whereas measures of

5. environmental conditions seldom are taken over such extensive periods. Moreover, such
measurements normally are not taken for each individual location in a building. Thus, it is perhaps
not surprising that little association between self-reported symptoms and measured IAQ may be
found.
Conclusions
SBS is a syndrome primarily caused due to inadequate ventilation, contaminants from indoor sources (like
building materials, furniture), poor thermal, visual or audio environment and is required for evaluating IAQ.
It is essential to estimate SBS score in order to relate subjective evaluation of the building with measured
concentration data of indoor air pollutants. SBS score is also supportive in categorizing the building i.e.
problem building (SBS or BRI) or healthy building etc., which may further help in devising maintenance
manual for building managers.
References
1. Berglund, B., Berglund, U., Lindval, T., 1984: “ Characterization of Indoor Air Quality and ‘Sick
Buildings’, ” AT-84-20 No. 1, Vol.90 part 1B pp.1045-1055
2. Berglund, B, Lindval, T., 1986: “Sensory Reactions to ‘Sick Buildings’ Environmental International,
Vol.12 pp147-159
3. Lane, Charles A., Woods, James E., Bosman, Thomas A., 1989: “ Indoor Air Quality Procedures for
Sick and Healthy Buildings” ASHRAE Journal, Vol.31 No.6 pp.48-52
4. Katiyar, V., 2002: “ Indoor Air Quality Monitoring at Offices/ Commercial Complexes” Annual
progress report (July 2001-July 2002). Submitted to Dept. of science & Technology, Technology
Bhawan, New Delhi. Research Center: Environmental Engg. Section, Indian Institute of Technology,
Delhi.
5. Raw, G.J., Roys, M.S., Whitehead, C., Tong, D., 1996: “Questionnaire Design for Sick Building
Syndrome: An Empirical Comparison of Options” Environment International, Vol.22 No.1 pp.61-
72.
6. Rotton, J., White, S.M., 1996: “Air Pollution, the Sick Building, and Social Behavior”
Environmental International, Vol.22 No.1 pp.53-60.
7. Sundell, J.,1996: “ What We Know, and Don’t Know About Sick Building Syndrome” ASHRAE
Journal, Vol.38 No.6 pp.51-57.
8. USEPA online publication 402-F-94-004, 1991: Indoor Air Facts No. 4 (revised): Sick Building
Syndrome
9. Wyson, David P., 1992: “Sick Buildings and the Experimental Approach” Environmental
Technology, Vol.13 pp.313-322.
10. Yeung, Au Y.N., Chow, W.K., Lam, Veronica Y.K., 1991: “Sick Building Syndrome- A Case
Study” Building and Environment, Vol.26 No.4 pp.319-330.
11. Wilson, S. and Hedge, A., 1987: The Office Environment Survey: A Study of Building Sickness,
Building Use Studies Ltd., London, U.K.
12. World Health Organization, 1983: Indoor air pollutants: exposure and health effects. EURO Reports
and Studies 78, World Health Organization.
ECRD.IN

6. APPENDIX
Sick Building Syndrome Symptoms Questionnaire
This survey is being conducted to determine the environmental quality of your building. This questionnaire
asks about your office environment, your work and your health. Please answer these questions as accurately
and completely as you can, regardless of how satisfied or dissatisfied you are with the conditions in the
office. All of your answers will be treated in strict confidence.
I. General Information
1. Room no……….. Floor……….. Date……….
2. Sex M….. F…...
3. Age …….under 20 ……..20-29 ……30-49
……..40-49 ……..50-59 …….over 59
II. Work Place Information
1. How long have you, worked in this building, to the nearest year?
______ years
2. If less than I year, how many months have you worked in this building?
______ months
3. On average, how many HOURS per WEEK do you work in this building?
______ hours per week
4. Which best describes the space in which your current workstation is located?
 Private office (1)
 Shared private office (2)
 Open space with partitions (3)
 Open space without partitions (4)
 Other (5)
5. How many people work in the room in which your workstation is located (including yourself)?
__1 __2-3 __4-7 __8-10 __ 11 or more
6. Is there carpeting on most or all of the floor at your workstation?
____Yes ___No
7. In general, how clean is your workplace area?
 Very clean (1)
 Reasonably clean (2)
 Somewhat dusty or dirty (3)
 Very dusty or dirty (4)
8. Please rate the lighting at your workstation.
 Much too dim (1)
 A little too dim (2)
 Just right (3)
 A little too bright (4)
 Much too bright (5)
9. How comfortable is the current setup of your desk or worktable?
(i.e. height and general arrangement of the table chair and equipment)
 Very comfortable (1)
 Reasonably comfortable (2)
 Somewhat uncomfortable (3)
 Very uncomfortable (4)
 Don’t have one specific desk or work table (5)
10. About how many hours per day do you work with a computer or word processor, to the nearest hour?
____Hours per day ____Don’t use one
11. If you use a computer or a word processor, do you usually use glasses when you use these machines?

7. ___ Yes ___No
III. Description of work Place Conditions
1. During the Past Three Months, have the following changes taken place within 15 feet of your current
workstation?
YES (1) NO(2)
New carpeting
Walls painted
New furniture
New partitions
New wall covering
Water damage
2. What is your tobacco smoking status?
 Never smoked (1)
 Fornler smoker (2)
 Current smoker (3)
3. Do you consider yourself especially sensitive to the presence of tobacco smoke?
___ Yes ___ No
4. Do you consider yourself especially sensitive to the presence of tobacco smoke in the air of your
workplace?
___ Yes ___No
5. Today, while working at your usual workstation, did you experience this environmental condition?
Conditions YES NO
Too much air movement
Too little air movement
Temperature too hot
Temperature too cold
Air too humid
Air too dry
Tobacco smoke odours
Unpleasant chemical odours
Other unpleasant odours
(e.g. body odour, food odour, perfume)
IV. Health
1. Have you ever been told by a doctor that you have or had any of the following?
YES NO
Sinus infection
Asthma
Migraine
Eczema
Hay fever
Allergy to dust
Do you feel symptoms while working in the room?
2. Irritation in the eyes ___Often ___Sometimes ___Never
3. Irritation in the nose ___Often ___Sometimes ___Never

8. 4. Dryness in mucous ___Often ___Sometimes ___Never
Membrane (throat etc.)
5. Lethargy/drowsy/tired ___Often ___Sometimes ___Never
6. Dryness on the face/ hands ___Often ___Sometimes ___Never
7. Do you get headache? ___Often ___Sometimes ___Never
V. Characteristics of your job
1. What is your job category?
___Managerial (1)
___Professional (2)
___Technical (3)
___Secretarial or clerical (4)
___Other (Specify) (5)
2. All in all, how satisfied are you with your job? / What do you feel with your job?
___ Very satisfied (1)
___ Some what satisfied (2)
___ Not too satisfied (3)
___Not at all satisfied (4)
3. What is your rating for the stress in work?
___ Very high (1)
___ High (2)
___ Average (3)
___ Low (4)
___ Very low (5)
VI. Overall Subjective Rating for the Working Area
1. Do you like the internal environment? ___ Yes ___ No
2. What is your feeling towards the working area?
___ Very comfortable (1)
___ Acceptable (2)
___ Comfortable (3)
___ Uncomfortable (4)
___Very uncomfortable (5)
3. Do you find that some / all of the symptoms you experienced as stated in IV also occurred in the past
during office hours?
____ Very often ____ Seldom ___ Sometimes ___ Never
4. Do you find that these symptoms are more obvious at the beginning of the week e.g. on Mondays
and Tuesdays?
____ Yes ___ No
5. Do you have any other comments on the internal environment?
_________________________________________________________________________________
_________________________________________________________________________________
_________________________________________________________________________________
Thank you for completing this Questionnaire