&EPA
United States
Envrionmental Protection
Agency
Indoor Environments Division
Office of Radiation and Indoor Air
(6609J)
EPA402-F-00-009
August 2000
The Problem
The Cause
The Consequences
",ent data
ingest that poor
-^,~
\Q can reduce a
Arson's ability to
Perform specific
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igntal tasks, _
miring concen-
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'ation, calculation
—
or
Indoor Air Quality
and Student Performance
How Does Indoor Air Quality Affect A Child's Ability To Learn?
Poor indoor air quality (IAQ) can cause illness requiring absence from school, and can
cause acute health symptoms that decrease performance while at school. In addition,
recent data suggest that poor IAQ can reduce a person's ability to perform specific mental
tasks requiring concentration, calculation, or memory.
Air in most indoor environments contains a variety of particles and gaseous contaminants.
These contaminants are commonly referred to as indoor pollutants when they affect
human health and performance. Indoor temperature and relative humidity can also
affect health and performance directly, and can affect human performance indirectly by
influencing the airborne level of molds and bacteria.
Most often, poor indoor air quality results from the failure to follow practices that help
create and maintain a healthy indoor environment. Common examples include failure to:
Control pollution sources such as art supplies and laboratory activities
Control temperature and humidity
Control moisture and clean up spills
Ventilate each classroom adequately
Adequately perform housekeeping and maintenance operations
Use integrated pest management to minimize the use of pesticides
Failure to deal adequately with any of these issues may go unnoticed, but can and often
does take its toll on health, comfort, and performance.
Specific Studies
Schools should be designed, built, and maintained in ways to minimize and control
sources of pollution, provide adequate exhaust and outdoor air ventilation by natural and
mechanical means, maintain proper temperature and humidity conditions, and be respon-
sive to students and staff with particular sensitivities, such as persons with allergies or
asthma. Adverse consequences can easily result when IAQ problems are not addressed
properly.
Effects from Building-Related Illnesses
Children do not perform as well when they are sick or absent from school. Indoor air
quality problems can result in absences because of respiratory infections/allergic diseases
from biological contaminants, or irritant reactions to chemicals used in virtually every
part of the school. Some conditions in the school environment are closely associated with
the incidence of sick building syndrome and asthma symptoms1'2, and asthma-related
illness is one of the leading causes of school absenteeism, accounting for over 10 million
missed school days per year.3 In addition, persons with asthma or other sensitivities may
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Asthma-related
illness is one of the
leading causes of
school absentee-
ism, accounting
for over 10 million
missed school days
per year.
1, 1 H
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• 111
have reduced performance in,the presence of environmental factors that trigger their
asthma. All of these "building-related illnesses" result from the lack of effective indoor
environmental quality management. In extreme cases, schools sometimes have to be
closed until problems are investigated and solved.
Effects from Mild Symptoms of Distress
What about people who do not have a diagnosable illness, but simply don't feel well?
People may report feeling lethargic, having headaches, having a mild sore throat or itchy
eyes; or they may have a sense that the air is "stale," "stuffy," or "too dry." When these
types of symptoms are made worse by being in a building, they, are referred to as "sick
building syndrome."
Estimated Loss in Performance
Motivation can often overcome small burdens of environmental stress so that children's
performance may not decline, However, continued environmental stress can drain
children's physical and mental resources and ultimately affect their performance.
Evidence from office workers suggests that when individuals experience just two
symptoms of discomfort, they begin to perceive a reduction in their own performance.
That perception increases as the number of symptoms increases, averaging a 3% loss
with 3 symptoms, and an 8% loss with 5 symptoms.4 It follows that when large numbers
of students and staff experience signs of discomfort related to the air inside their school,
teaching and learning performance will likely degrade over time.
Measured Loss in Performance
Studies relating direct performance measurements to changes in indoor air quality are just
now emerging. For example, a recent European study of 800 students from eight different
schools provides data on IAQ, health symptoms, and students' ability to concentrate.5 In
the study, carbon dioxide measurements were taken in the classrooms, and students were
given a health symptom questionnaire. A computer-based program scored their ability to
concentrate. Carbon dioxide itself is not a health threat at levels found indoors, but since
the main source of carbon dioxide in buildings is exhaled breath, and the main mechanism
for removal is ventilation, high carbon dioxide levels in classrooms are an indication of low
ventilation rates and, therefore, high levels of pollution. In classrooms where carbon
dioxide levels were high (low ventilation rates), student scores on the concentration tests
were low; and their health symptom responses were high. The results were statistically
significant and tend to confirm that with IAQ management, including source control and
adequate ventilation, student performance can improve.
Another controlled study of adults shows a similar relationship between the presence or
absence of an indoor pollution source, health symptoms, and mental function.6 In this study,
a health symptom questionnaire was completed by 30 female subjects who performed
various kinds of mental tasks typical of office work in groups of six at a time. They worked
in a realistic office environment specifically designed to have good IAQ, with low pollution
levels. Because carpeting that is not adequately maintained can sometimes act as a source
of pollution, a 20-year-old used'carpet from another building was used to represent a
potential pollution source. The carpet was periodically introduced on racks behind a screen
so that subjects had no way of knowing when the carpet was present. The women were
tested in typing, arithmetic, logical reasoning, memory, and creative thinking during several
trials with and without the carpet present. During the trials without the pollution source, the
subjects' performance was unproved. The number of words typed increased 6.5%*, typing
errors were reduced by 5%***, the addition test scores increased 3.8%**, and logical
reasoning test scores improved by 3-4%***. When the pollution source was present, there
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Continued
environmental
stress can drain
children's physical
and mental
resources and
ultimately affect
their performance.
~^sr
was an increased prevalence of headaches during tasks requiring concentration,
suggesting that at least part of the affect on performance was from pollution-related
adverse health effects. In a later study using the same procedure, increasing
ventilation rates also provided a statistically significant improvement in human
performance.7
* Statistically significant at 99%; ** at 95%; and *** at 90%
Measured Effects of Temperature and Humidity
In addition to indoor pollution and ventilation, studies confirm that various human
activities such as typing or driving a vehicle are diminished when people are
demonstrably too cold or too hot. Temperature is also implicated in studies of sick
building syndrome. Maintaining temperature at the high end of the comfort zone tends to
increase symptoms, while temperatures at the low end of the comfort zone tend to
reduce symptoms. Similarly, individuals perceive the quality of the indoor air to be
better when temperature and/or humidity are toward the low end rather than the high end
of the comfort zone. 8'9>1°
There is also good evidence that moderate changes in room temperature, even within the
comfort zone, affect children's abilities to perform mental tasks requiring concentration,
such as addition, multiplication, and sentence comprehension. Study results were differ-
ent for boys and girls, and the effects varied for different types of tasks. But, in general,
the evidence strongly supports the need to avoid extreme conditions and to provide for
as much individual temperature control as possible.11-12
Will Performance Be Affected Even If No One Is Complaining?
Performance can certainly be expected to suffer if conditions are serious enough for
people to complain. However, the lack of complaints is NOT an indication that perfor-
mance cannot be improved. For example, in the above studies, symptoms were solicited
through questionnaires (as opposed to complaints), and tests were performed on indivi-
duals in typical kinds of school and office environments. That is, the reductions in
performance were recorded in circumstances that could easily have gone unnoticed
because of the absence of complaints.
What You Can Do
School systems should take advantage of available programs such as the IAQ Took for
Schools Kit to improve and maintain good indoor air quality in their schools. Programs
can be targeted to the maintenance of existing school facilities and to new school
construction.
The U.S. Environmental Protection Agency has published voluntary guidance that
addresses indoor air quality in schools. The IAQ Tools for Schools Kit, is designed to
be a no-cost, or low-cost approach to improving indoor air quality. The Kit is free to
schools and school districts. To order the Kit:
EPA Kit
PO Box 37133
Washington, DC 20013-7133
Fax: 703-356-5386 or call: 1-800-438-4318
Visit the IAQ Tools for Schools web site at www.epa.gov/iaq/schools and download
the Kit, learn about training opportunities, and read about schools around the country
who are using the Kit.
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References
1. Smedje, G., and D. Norback. 1999. The School Environment-Is It Related to the Incidence
of Asthma hi the Pupils? In Indoor Air '99. The Eighth International Conference on Indoor ,
Air Quality and Climate. Vol 5, pp. 445-450.
2. Daisey, Joan M., and William J.Angell. 1999. Indoor Air Quality, Ventilation and Health
Symptoms in Schools: An Analysis of Existing Information, la Indoor Air 99. The Eighth
International Conference on Indoor Air Quality and Climate. Vol 2, pp. 1-6.
3. Asthma and the Environment: A Strategy to Protect Children. President's Task Force on
Environmental Health Risks and Safety Risks to Children. January 28,1999.
4. Raw, G.J., M.S. Roy, and A. Leaman. 1990. Further Findings from the Office Environment
Survey: Productivity. Is. Indoor Air '90. The Fifth International Conference on Indoor Air
Quality and Climate. Vol 1, pp. 231-236.
5. Myhrvold, A.N., E. Olsen, and 0. Lauridsen. 1996. Indoor Environment in Schools - Pupils
Health and Performance in regard to CO2 Concentrations. ^IndoorAir '96. The Seventh
International Conference on Indoor Air Quality and Climate. Vol 4, pp. 369-371.
6. Wargocki, P., D. P. Wyon, Y. K. Baik, G. Clausen, and P. O. Fanger. 1999. Perceived Air
Quality, SBS-Symptoms and Productivity in an Office at Two Pollution Loads. In Indoor
Air 99. The Eighth International Conference on Indoor Air Quality and Climate. Vol 2,
pp. 131-136.
7. Personal communication. 1999. Personal email communication from P. O. Fanger to
David H.Mudarri. 12/23/99.
8. Farig, L., G. Clausen, and P. O. Fanger. 1998. Impact of Temperature and Humidity on the
Perception of Indoor Air Quality. Indoor Air. Vol. 8, No. 2, pp. 80-90.
9. Fang, L., G. Clausen, and P.O. Fanger. 1998. Impact of Temperature and Humidity on
Perception of Indoor Air Quality During Immediate and Longer Whole-Body Exposures.
Indoor Air. Vol 8, No. 4, pp. 276-284.
10. Fang, L., P. Wargocki, T. Witterseh, G. Clausen, and P. O. Fanger. 1999. Field Study on the
Impact of Temperature, Humidity and Ventilation on Perceived Air Quality. In Indoor Air 99.
The Eighth International Conference on Indoor Air Quality and Climate. Vol 2, pp. 107-112.
11. Wyon, D. P., IB. Andersen, and G. R. Lundqvist. 1979. The Effects of Moderate Heat Stress
on Mental Performance. Scand.J. Work Environ. & Health. 5:352-361.
12. Wyon, D.P. 1991. The Ergonomics of Healthy Buildings: Overcoming Barriers to Productivity.
InZ4.<2 '91: Post Conference Proceedings. American Society of Heating, Refrigerating, and
Air-Conditioning Engineers, Inc. Atlanta, pp. 43-46.
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