IAQ Backgrounder
Indoor Air Quality
goal of the Checklist is to provide
clear and easily applied activities that you
can use to help prevent indoor air quality
problems and resolve any problems
promptly if they dp arise. Once you
understand the basic principles and factors
that influence indoor air quality in your
school, you will note that the specific
activities involve two major actions - the
management of pollutant sources, and the
use of ventilation for pollutant control. This
guidance is based on the following
principles:
» Many IAQ problems can be prevented by
school staff and students.
When IAQ problems do arise, they can
often be resolved using the skills of
school staff.
The expense and effort required to
prevent most IAQ problems is much less
than the expense and effort required to
resolve problems after they develop.
Why IAQ is Important to Your
School
Most people are aware that outdoor air
pollution can damage their health, but many
do not know that indoor air pollution can
also have significant harmful effects. U.S.
Environmental Protection Agency (EPA)
studies of human exposure to air pollutants
indicate that indoor levels of pollutants may
be 2-5 times, and occasionally more than
100 times, higher than outdoor levels.
These levels of indoor air pollutants may be
of particular concern because it is estimated
that most people spend about 90% of their
time indoors. Comparative risk studies
performed by EPA and its Science Advisory
Board have consistently ranked indoor air
pollution among the top five environmental
health risks to the public.
Failure to prevent indoor air problems, or
failure to respond promptly, can have
consequences such as:
increasing the potential for long term
and short term health problems for
students and staff
impacting the student learning
environment, comfort, and attendance
reducing performance of teachers and
staff due to discomfort, sickness, or
absenteeism
accelerating deterioration and
reducing efficiency of the school
physical plant and equipment
increasing the potential that schools
will have to be closed, or occupants
temporarily relocated
straining relationships among school
administration and parents and staff
creating negative publicity that could
damage a school's or administration's
image and effectiveness
creating potential liability problems
Indoor air problems can be subtle and
do not always produce easily recognized
impacts on health, well-being, or the
physical plant Children may be
especially susceptible to air pollution.
For this and the reasons noted above, air
quality in schools is of particular
concern - proper maintenance of indoor
air is more than a "quality" issue, it
encompasses safety and stewardship of
our investment in the students, staff, and
facilities.
UhdentandnglAQPiobleimand
Solutions
Over the past several decades, exposure
to indoor air pollutants has increased
due to a variety of factors, including the
Tools for Schools
Good indoor air
quality contributes
to a favorable
teaming environment
for students,
performance of
teachers and staff,
and a sense of
comfort, health and
well-being for all
school occupants.
These combine to
assist a school in
its core mission
educating children.
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construction of more tightly sealed
buildings, reduced ventilation rates to
save energy, the use of synthetic
building materials and furnishings, and
the use of chemically-formulated
personal care products, pesticides, and
housekeeping supplies. In addition, our
activities and our decisions, such as
deferring maintenance to "save" money,
lead to problems from sources and
ventilation.
Four basic factors affect IAQ: sources of
indoor air pollutants, heating,
ventilation, and air-conditioning
(HVAC) system, pollutant pathways,
and occupants.
Soucesof Moor Ar Mutants
Indoor air contaminants can originate
within the building or be drawn in from
outdoors. If pollutant sources are not
controlled, IAQ problems can arise,
even if the HVAC system is properly
operating. Air pollutants consist of
numerous particulatcs, fibers, mists,
bioaerosols, and gases. It may be helpful
to think of air pollutant sources as fitting
into one of the categories in the table
shown below.
In addition to the number of potential
pollutants, another complicating factor
is (hat indoor air pollulanl concentration
levels can vary by time and location
within the school building, or even a
single classroom. Pollutants can be
emitted from point sources, such as
from science store rooms, or from area
sources, such as newly painted surfaces,
and pollutants can vary with time, such
as only once each week when floor
stripping is done, or continuously such
as fungi growing in the HVAC system.
Typical Sorces of Moor ArPMutants
Outjkfe Scutes
Fbfahd Outdoor As-
Pollen, dust, fungal
spores
Industrial emissions
Vehicle emissions
NMfaySoucM
Loading docks
Odors from dumpsters
Unsanitary debris or
building exhausts near
outdoor air intakes
UuttajjiuundSouncw
Radon
Pesticides
Leakage from
underground storage
tanks
HVACEwmmt
Microbiological growth in
drip pans, ductwork, coils,
and humidifiers
Improper venting of
combustion products
Dust or debris in ductwork
Emissions from office
equipment (volatile
organic compounds,
ozone)
Emissions from shops,
labs, cleaning processes
Microbiological growth
on soiled or water-
damaged materials
Dry traps that allow the
passage of sewer gas
Materials containing
volatile organic
compounds, inorganic
compounds, or damaged
asbestos
Materials that produce
particles (dust)
RnMngi
Emissions from new
furnishings and floorings
Microbiological growth
on or in soiled or water-
damaged furnishings
OtfurhdoorSouross
Science laboratories
Vocational arts areas
Copy/print areas
Food prep areas
Smoking lounges
Cleaning materials
Emissions from trash
Pesticides
Odors and volatile
organic compounds from
paint, chalk, adhesives
Occupants with
communicable diseases
Dry-erase markers and
similar pens
Insects and other pests
Personal care products
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i .
Optional Location for
Unit Ventilator
Cr<: !^_ ?$§
Exhaust Air Through
Central Room
Vent <* Vent
Outdoor Air
Supply
HVAC System Demand Operation
The heating^ ventilation, and air-
conditioning (HVAC) system includes
all heating, cooling, and ventilating
equipment serving a school. A properly
designed and functioning HVAC system:
controls temperature and humidity to
provide thermal comfort
distributes adequate amounts of
outdoor air to meet ventilation needs
of school occupants
isolates and removes odors and
pollutants through pressure control,
filtration, and exhaust fans
Not all HVAC systems are designed to
accomplish all of these functions. Some
buildings rely only on natural
ventilation. Others lack mechanical
cooling equipment, and many function
with little or no humidity control. The
two most common HVAC designs used
in schools are unit ventilators and
central air handling systems. Both can
perform the same HVAC functions, but
the central air handling unit serves
multiple rooms while the unit ventilator
serves a single room.
The three building figures in this
Backgrounder show typical methods for how
outdoor air enters a room, and how exhaust
air exits through a vent If exhaust airflow
through door or wall grilles into corridors is
sealed due to fire codes, ensure that air has
another path to reach the central exhaust
Airflow patterns in buildings result from the
combined forces of mechanical ventilation
systems, human activity, and natural effects.
Air pressure differences created by these
forces move airborne pollutants from areas
of higher pressure to areas of lower pressure
through any available openings in building
. walls, ceilings, floors, doors, windows, and
HVAC system. An inflated balloon is an
example of this driving force. As long as the
opening to the balloon is kept shut, no air
will flow, but when open, air will move from
inside (area of higher pressure) to the
outside (area of lower pressure).
Even if the opening is small, air will move
until the pressures inside and outside are
equal. '
How outdoor air is
supplied through a unit
ventilator.
Typical supply vents and
return/exhaust grilles.
tooted only on callings, not wall*
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BuUhgOccupanb
Building occupants in schools include
the staff, students, and other people who
spend extended periods of time in the
school. The effects of IAQ problems on
occupants are often non-specific
symptoms rather than clearly defined
illnesses. Symptoms commonly
attributed to IAQ problems include:
headache, fatigue, and shortness of
breath
sinus congestion, cough, and
sneezing
eye, nose, throat, and skin irritation
dizziness and nausea
All of these symptoms, however, may
also be caused by other factors, and are
not necessarily due to air quality
deficiencies. Environmental stressors
such as improper lighting, noise,
vibration, overcrowding, poor
ergonomics, and psychosocial problems
(such as job or home stress) can produce
symptoms that are similar to those
associated with poor air quality, but
require different solutions.
Because of varying sensitivity among
people, one individual may react to a
particular IAQ problem while
surrounding occupants do not display ill
effects. In other cases, complaints may
be widespread In addition to different
degrees of reaction, an indoor air
pollutant or problem can trigger
different types of reactions in different
people. Groups that may be particularly
susceptible to effects of indoor air
contaminants include, but are not limited
to:
allergic or asthmatic individuals, or
people with sensitivity to chemicals
people with respiratory disease
people whose immune systems are
suppressed due to radiation,
chemotherapy, or disease
contact lens wearers
Hew outdoor air is
supplied in a central air
handling system.
Centra Air HonoDng Unfi
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SixBasicControlStrategies
There are six basic control methods for
lowering concentrations of indoor air
pollutants. Specific applications of these
basic control strategies are noted in your
Checklists. . .
Source Management includes
source removal, source substitution, and
source encapsulation. Source
management is the most effective
control method when it can be
practically applied. Source removal is
very effective. However, policies and
actions that keep potential pollutants
from entering the school are even better
at preventing IAQ problems. Examples
of source removal include not allowing
buses to idle near outdoor air intakes,
not placing garbage in rooms with
HVAC equipment, and banning smoking
within the school. Source substitution
includes actions such as selecting a less
toxic art material or interior paint than
the products which are currently in use.
Source encapsulation involves placing a
barrier around the source so that it
releases fewer pollutants into the indoor
air (e.g., asbestos abatement, pressed
wood cabinetry with sealed or laminated
surfaces).
Local Exhaust is very effective in
removing point sources of pollutants
before they can disperse into the indoor
air by exhausting the contaminated air
outside. Well known examples include
restrooms and kitchens where local?
exhaust is used. Other examples of
pollutants that originate at specific
points and mat can be easily exhausted:
include science lab and housekeeping
storage rooms, printing and duplicating.
rooms, and vocational/ industrial areas
such as welding booths.
Ventilation through use of cleaner
(outdoor) air to dilute the polluted
(indoor) air that people are breathing.
Generally, local building codes specify
Outdoor Air
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Hnfows
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the quantity (and sometimes quality) of
outdoor air that must be continuously
supplied to an occupied area. For
situations such as painting, pesticide
application, or chemical spills,
temporarily increasing the ventilation
can be useful in diluting the
concentration of noxious fumes in the
air.
Exposure Control includes adjusting
the time of use and location of use. An
example of time of use would be to strip
and wax floors on Friday after school is
dismissed, so that the floor products
have a chance to off-gas over the
weekend, reducing the level of odors or
contaminants in the air when the school
is occupied. Location of use deals with
moving the contaminating source as far
as possible from occupants, or
relocating susceptible occupants.
Air Cleaning primarily involves the
filtration of particles from the air as the
air passes through the ventilation
equipment Gaseous contaminants can
also be removed, but in most cases this
type of system should be engineered on
a case-by-case basis.
How outdoor air is
supplied in an exhaust-
only system.
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Teacher's
Administrative Staff
Health Officer's
Ventilation
Building Maintenance
FoodService
Waste Management
Renovation and Repairs
Walkthrough
Education of the school occupants
regarding IAQ is critical. If people are
provided information about the sources
and effects of contaminants under their
control, and about the proper operation
of the ventilation system, they will better
. understand their indoor environment, and
am act to reduce their personal
exposure.
YourRotointhelAQTeam
As one of the people in your school, .
your activities and decisions have>an
impact on the quality of the indoor air in
your school. You can participate by
applying the activities noted in your
Checklist, and by continuing to apply
these principles on a daily basis.
Someone from your school or district
has taken the role of IAQ Coordinator,
and serves as a focal point for collecting
IAQ information and handling IAQ
concerns.
How Do You Know if You Have an
lAQtafabm
Diagnosing symptoms that relate to IAQ
can be tricky. Acute (short-term)
symptoms of IAQ problems typically
are similar to those from colds, allergies,
fatigue, or the flu. There are clues that
can serve as an indicator of a potential
indoor air problem:
the symptoms are widespread within
a class or within the school
the symptoms disappear when the
students or staff leave the school
building for a day
the onset is sudden after some change
at school, such as painting or pesticide
application
persons with allergies, asthma, or
chemical sensitivities have reactions
indoors but not outdoors
a doctor has found that a student or
staff member has an indoor air-related
illness
However, a lack of symptoms does not
ensure that IAQ is acceptable.
Symptoms from long-term health effects
(such as lung cancer due to radon) often
do not become evident for many years.
What if Yo« Think You Have an
If you receive complaints that seem to
indicate a potential IAQ problem and the
problem is self-evident, then attempt to
correct the problem. If the problem
cannot be corrected, or if the complaint
seems to indicate a potentially severe
IAQ problem, contact the IAQ
Coordinator immediately. The IAQ
Coordinator may ask you questions to
try to identify whether you have
overlooked potential causes of the
problem (such as, "Has anything
changed since the last time you
completed your Checklist?^, and then
may call in other help from within or
outside the school to investigate further.
. Because indoor air problems can
jeopardize the health of students and
.staff, parents and the public may react
strongly to reports of bad indoor air
quality in your school. With this in
mind, it is recommended that you follow
the communications guidelines
established by the IAQ Coordinator.
Usually, this will involve referring
questions from the public and media to
one central source, the IAQ Coordinator
for your school. In this way, students,
parents, staff, and the public will not
become alarmed by conflicting or wrong
information, and will have a consistent
and complete source of information
regarding the quality of the indoor air in
your school.
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